Tallgrass Savanna
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1. Little bluestem-live oak savanna- This is the Texas live oak-tallgrass savanna at climax stage. As a single-species understory to old-growth live oaks, little bluestem forms a consociation almost to complete exclusion of any other herbaceous species. The only contender (and it is barely that) for an associate species is, interestingly, the annual colonizer of old-fields known variously as marestail, horse-weed, or old-field fleabane (Conyza canadensis= Erigerion canadensis). There is good regeneration of the live oak. (Note young trees at far left margin of slide and the clump of young trees with gray trunks immediately behind and to the right of the the right front mature live oak.) A bromeliad known as ball moss (Tillandsia recurvata) is growing on branches of the live oaks. This is as beautiful and pristine a savanna as the author ever encountered.

Atascosa County, Texas. Autumnal aspect, October. As was the case of the live oak-mixed prairie savannah this vegetation defies precise FRES and Kuchler designations, primarily perhaps because these classifications did not involve mapping  at this fine a scale. This community could be interpreted as a cover type variant or form  of K-72 (Oak Savanna) though in physiogonomy it clearly resenmbles the Florida live oak hammock which seemed to be most closely K-81 (Live Oak-Sea Oats). Yet, it is not the coastal live oak- sea oats understory. Neither is there an SRM designation. East Central Texas Plains- Southern Post Oak Savanna Ecoregion, 33b (Griffith et al., 2004).

The Cross Timbers is, or are (as the grammatical case may be), some of the more unique and enigmatic kinds (or forms, expressions, etc.) of vegetation in North America. Besides being used as a term for a “vegetation type” and an ecosystem or landscape of a geographic region-scale, Cross Timbers also entered into regional history, literature, and cultural-social character features. Washington Irving  probably did the most to essentially enshrine Cross Timber[s] in his famous A Tour on the Prairies (1835). Later, Cross Timbers became a long-established trademark-like catch word for commercial use in regional promotion of real estate, tourism, and so on. Cross Timbers took on poetic and historic connotations as well as general biological and specific ecological meanings and descriptions. By and large these different usages, views, or ways of seeing the Cross Timbers complemented each other and made for a term or term-like phrase equal in its own way with the likes of Great Plains, Piedmont, Edwards Plateau, pine barrens, Great Lakes forests, Flint Hills, Ozarks, Great Basin, Palouse Prairie, or Pacific Northwest.  In these instances of common common “every day”usage, at least with some groups of people, Cross Timbers as the specific name of a physiographic province or plant formation became merged in common parlance with the general name for a region which in turn might be a combination of strict geologic or cartographic interpretation with basic biological features and historic-economic-cultural characteristics. Such is the very definition of Geography, and Cross Timbers is a geographical as well as an ecological designation.

In this context, readers have been blessed with an outstanding treatise of the Cross Timbers in The Cast Iron Forest (Francaviglia, 2000). This comprehensive account along with Dyksterhuis (1948) and Bruner (1931), both of which were referred to below, will provide beginning students with all they need to know to understand the regional range community and the range cover type long recognized and designated the Cross Timbers. Another recent, and also outstanding, treatment of the Cross Timbers is that of Hoagland et al. in Anderson et al. (1999, ps. 231-245).

A thumbnail sketch of a few basic features of this range vegetation seemed in order. The Cross Timbers is generally a savanna as a transition zone between the westernmost outpost of the oak-hickory forest and the eastern edge of the great interior grasslands known as tallgrass prairie. The Cross Timbers is climax vegetation. This vegetation extends from Texas northward and slightly eastward to southern Kansas. Cross Timbers generally occurs on soils for which the parent material is sandstone of various geologic ages (Francaviglia, 2000, Fig. 1-8, p. 24). As tree-dominated or, at least, tree-containing communities in North America go, the Cross Timbers have probably been less altered by white man than most native vegetation of which trees are or were a major component. Lastly, but by no means completely, Cross Timbers remains a major range type from standpoints of both a subject in Plant Geography and Synecology and as natural resources having substantial economic and cultural importance. This is true in particular for the beef cattle industry.        

In Oklahoma, Cross Timbers occur on the Central Redbed Plains, the Eastern Sandstone Cuesta Plains (Francaviglia, 2000, p. 23), and northward through the Chautauqua Hills and Osage Questas physiographic provinces which extend through southeast Kansas on which Cross Timbers also developed and remain a climax range type. The older and more familiar names for the last three of these is Sandstone Hills and Chautauqua Hills or, more generally, Sandstone Hills (Fenneman, 1938, ps. 613-614, 616-617, Plate VI).

South of Oklahoma’s Red River the major physiographic provinces supporting Cross Timbers are the Redbeds Plains and Commanche Plateau (Fenneman, 1938, Plate VII), or bordering along the Edwards Escarpment and Lampassas Cut Plain of Texas (Fenneman, 1938, Fig. 27, p. 102). South of the Red River the Cross Timbers (ie. the Texas Eastern and Western Cross Timbers) are in the West Gulf Coastal Plain of the Coastal Plain Province (Fenneman, 1938, ps. 100-103). An instructive indication of the close relationship between physiographic province and general or regional plant community (sub-formations) was shown when Fenneman (1938) labeled on his plates and figures both the Eastern Cross Timbers and Western Cross Timbers.

The Cross Timbers is (are) one of several ecotones or transitions between the deciduous forest formation of eastern North America and the climax tallgrass (Andropogon-Sorgastrum) prairie to the west. The definitive authority of the eastern deciduous forest remains Lucy Braun who interpreted the Cross Timbers as part of the "forest-prairie transition" of the oak-hickory forest region (Braun, 1950, ps. 177-178). Earlier in the seminal study of Oklahoma vegetation (Bruner1931, ps. 108- 110, 115-116, 129, 142-148) treated the Cross Timbers as an "oak-hickory savanna". Dyksterhuis (1957, p. 437) applied savanna as a concept and term to the Cross Timbers. More recent descriptions and interpretations retained the savanna designation although Francaviglia (2000, p. 119) concluded that from more detailed accounts (especially one by W.L. Ormsby, Jr) Cross Timbers generally "referred both to a forest with a dense, nearly impenetrable understory as well as to a more open, savanna-type forest with fairly widely spaced oak trees".

6. Oklahoma Cross Timbers- This is a textbook view of Cross Timbers in the Osage Questa province in Excellent range condition class. This is a Shallow Savannah range site dominated by the Four Horsemen of the Prairies with tall dropseed, purpletop (Tridens flavus), beaked panicum, and sand lovegrass as associates. Blackjack and post oaks are the dominat trees with hickory and American and red elm scattered.

"As I sit here today many miles I am away,
from the place I rode my pony through the draw;
Where the oak and blackjack trees
kiss the playful prairie breeze,
in the Oklahoma hills where I was born."

---- Oklahoma Hills, Woody Guthrie

7. Detailed interior view of post oak-dominated and brush understory form of Cross Timbers (Oklahoma)- This is a three-layered (-storied) Cross Timbers community growing in the heart of the Sandstone Hills. The understorey consisted of two layers. The taller layer (hence middle storey between tree canopy and lower shrub storey) consisted of redbud and cedar elm as shrubs or lower-stature trees entangled with vines (lianas) of greenbriar and grape. The lowest storey was dominated by the short, colony forming shrub generally known as buckbrush (Symphoricarpos orbiculatus). Seedlings and saplings of post oak were components of both these layers, hence of all layers of this vegetation. The most common herbaceous species was the rather infrequent coneflower commonly called blackeyed susan (Rudbeckia hirta).

This local Cross Timbers community had been excluded from burning for a number of years. Consequently it developed this multi-storied architecture of woody plants instead of the natural, open understorey comprised primarily of herbaceous species.  The vegetation seen here should be compared to the local Cross Timbers community shown in the next three photographs. The latter had been subjected to some recent surface fire(s) and had the herbaceous understorey characteristic of the climax Cross Timbers savanna.  

8.  Interior view of Oklahoma Cross Timbers with open herbaceous understorey – This is an example of a well-developed (and well-managed) climax Cross Timbers community with post oak and blackjack oak co-dominant and black hickory (Carya texana) the associate tree species. Often one or the other of these two oak species is the dominat of a Cross Timbers stand with the other species being either the associate or, sometimes, infrequent to absent. This condition is manifested as either a post oak or blackjack oak form or subtype. Bruner (1931, ps. 143-146) explained that blackjack was better adapted to drier, sandier, and generally less favorable habitats than post oak. He reported that blackjack was generally an inferior competitor with more tolerant, mesic species but that a mixture of both of these oaks was “… characteristic where the association [oak-hickory savanna] is well developed” (Bruner, 1931, ps. 146-147). In this section of his monograph Bruner (1931, esp. p. 147) listed the third dominant as Hicoria buckleyi (black or Buckley’s hickory formerly named C. buckleyi and, earlier, as H. buckleyi and now identified as C. texana) which he found to be more common on more favorable local habitats especially those with soils of higher clay content and on north or east slopes (ie. more mesic micro-sites). 

All three of the dominants of the oak-hickory savanna association were well-represented (common and widely distributed) in the stand shown in this and the next two slides. These three photographs caught the Oklahoma Cross Timbers at ultimate development. These examples, complete with the  “clear” herbaceous understorey maintained by fire, showed this range cover type at its zenith.Vegetation seen in these three slides should be compared back to the immediately preceding slide which showed vegetation of unburnt Cross Timbers on similar habitat (the same range site).   Dominant herbaceous species was upland switchgrass, which was consistent with this more mesic site as indicated by abundance of black hickory. Canada wildrye appeared to be the second most common grass (and, in fact, was a local dominant on some micro-sites) while the associate herb was the forb, black- (= brown-) eyed susan, that appeared very conspicuous in this view.

The foremost tree was post oak while the other two large trees to the right of the post oak were blackjacks. 

9.  Interior view of Cross Timbers in Sandstone Hills of central Oklahoma- This is the second of three photographs that presented a detailed view inside of a well-developed community of Oklahoma Cross Timbers that approached species composition of the climax vegetation.. Dominant tree species were post and blackjack oaks with black hickory as the associate tree species. The tree in right foreground was a mature (though not ancient) black hickory. The bark, shape of bole, and leaves were representative of this species. Trees in background were primarily young post oaks. Conspicuous forb was black-eyed susan. Switchgrass, Canada wildrye, and beaked panicgrass were dominant grasses in roughly that order. An unidentified sedge (Carex) species was also present. Species present were primarily those of the climax vegetation, but their relative proportions were a departure from the composition of the climax savanna. “Guestimated” percentages (based on rough estimates of cover, density, etc.) of herbaceous species were reduced while those of the woody species were increased over that described for pre-Columbian vegetation (hypothetical reconstructions based on examples of relict vegetation, early journal accounts, succcessional studies, etc. used as the basis of range site descriptions). Relative small size and juvenile age of most trees (eg. those in background) suggested that there were recent increases in tree regeneration and canopy cover most likely due to fire suppression and related human-induced impacts such as periodic overgrazing or vehicular traffic. The presence of black hickory, the most mesic of major Cross Timbers tree species, indicated that this site on a north slope was favorable for growing a dense stand of trees in the unnatural absence of natural, recurrent fire. Note, however, that some fairly recent surface fire(s) had “cleaned up” (to a degree) the understory such that there was an herbaceous understorey rather than the “brush patch” or “tangle” architecture of unburnt Cross Timbers such as that shown two slides above this photograph. 

10.   Interior of Cross Timbers in Sandstone Hills of central Oklahoma- This is the last of three slides that showed a typical interior of well-developed Oklahoma Cross Timbers. Vegetation consisted of climax species but not with the climax proportions of those species there having been an increase in tree density and canopy cover with some human disturbances (primarily reduction in natural fire). The Cross Timbers community shown in this and the two slides immediately above had been subjected to some relatively recent fire(s) with the resultant open herbaceous understorey. This interior architecture should be compared to that of unburned Cross Timbers which allowed development of a dense woody understorey (complete with two or three layers of woody plants). An example of this “thicket-like” form of Cross Timbers that results from fire exclusion was presented in the third slide above this one. Even with recent “burning off of the woods” the Cross Timbers vegetation shown in this and the two preceding slides had been fired so infrequently relative to the estimated historic fire regime that the community was more a woodland than a savanna.

Trees in the foreground were blackjack oak (the left-most tree and the two right-most and closest foreground trees) and post oak (two remaining trees; the second on the left and the one behind and to the left of the right-front blackjack). Dominant (and conspicuous) grass was switchgrass with Canada wildrye and beaked panicgrass also prominent. Dominant forb was black-eyed susan.

11.  Scrub blackjack oak form of Cross Timbers- Blackjack oak dominates the Cross Timbers on the harsher (drier, shallower) sites. This was explained above under slides of Oklahoma Cross Timbers using descriptions cited from the classic, definitive works (eg. Bruner, 1931, Francaviglia, 2000). Shown here was a consociation of the scrub or shrub form of blackjack. This can be compared to the tree form of this species shown in the immediately preceding and immediately succeeding slides. The blackjacks shown in these slides grew on a north slope and hillcrest of a north slope, respectively, whereas the blackjacks shown here grew on a south slope. It was the same range site (Shallow Savanna) in all slides with the major difference being north- versus south-slope aspect. However, a most interesting phenomenon and comparison between these habitats was that upland switchgrass was the dominant understorey species on all three! The unmistakable leaves and panicles of switchgrass were prominent in the left foreground of the present slide. Switchgrass grew only at edges of and in interspersed openings among the larger thickets of blackjack. The hard, undecomposed leaves that had fallen from the blackjacks formed mats or mulches around bases of the shrubs that were from two to six inches in depth. Leaf litter combined with the shade from green leaves on the oaks effectively excluded all other plant species from the blackjack thickets. Such layering of blackjack leaves from several previous seasons was ready fuel for fire. Any such fire would scourch the blackjacks to the point of top-killing them resulting in more swithcgrass and smaller blackjacks (following regrowth) with less woody cover. The unnaturally high proportion of blackjack cover seen here is a disturbance climax brought about by man’s elimination or, at least, reduction of natural fire regimes.

12.   Blackjack oak-dominated Cross Timbers in Sandstone Hills of central Oklahoma- This is the blackjack oak form or phase of Cross Timbers savanna with unusually high recruitment of oak and consequent exclusion of herbaceous species. This single-species stand (consociation) of blackjack oak developed on a rocky hilltop on the crest of a north slope.  All age classes of blackjack were present with older oaks growing into the tree form rather than the shrub or scrub oak form shown in the   immediately preceding slide. The older blackjacks were not as large as those photographed growing on north slopes with post oaks and black hickory, but the local habitat viewed here was more favorable than the shallow soil and south slope that restricted development to the scrub thicket formshown in the preceding slide. Also, present on this northern aspect hillcrest was a second layer of woody plants that was made up largely of buckbrush. Switchgrass (the dominant grass), little bluestem, Canada wildrye, and broomsedge bluestem were present but extremely sparse in small open spaces scattered among trees. None of these spaces or patches were visible here. An unidentified species each of Carex and of moss (Musci sp.) dominated microsites formed by shade from trees. This was visible in foreground of the view shown here.

13.  Blackjack oak trees top-killed by intense prescribed fire on tallgrass prairie- This and the following slide were included to show readers the size of blackjack trees that can be top-killed by fire on tallgrass prairie and associated savannahs like the Cross Timbers. Blackjacks over 15 feet in height were top-killed by an intense heading fire set at base of this slope and fueled by the dry matter (necromass) of tallgrass species (big bluestem was dominant with Indiangrass and little bluestem associates) that accumulated from deferment in the previous growing season. The prescribed burn was conducted about six weeks prior to the time of this photograph. It was a hot fire and totally killed all blackjack tissue above ground level.

This was big bluestem-dominated tallgrass prairie (the big bluestem phase or form of tallgrass prairie, bluestem prairie, which is more mesic than the Indiangrass and little bluestem-dominated forms). This form usually is more productive of biomass (higher-yielding) and produces more (perhaps not a lot more) fuel than the less moisture-requiring and generally lower-yielding latter two species. This bluestem prairie on the Osage Questas physiographic sub-province is part of a tallgrass prairie and oak-hickory-tallgrass savanna complex (a mosaic of these general, major communities) that also includes the Flint Hills to the west and the Chautauqua Hills “inserted” inside the Osage Questas. It is the sandstone-derived Chautauqua Hills that precisely speaking are part of the Cross Timbers, but blackjack and post oaks do not rigorously conform to such precise divisions as these which geologists and ecologists delight in delineating. Thus it was that blackjacks had “lite out from where they belong” in the adjoining Cross Timbers and invaded the pristine virgin sod of the bluestem and Indiangrass prairie pastures. Contemporary prairiemen took a lesson from the orally trasmitted knowledge of numerous Indian tribes that had at one time or the other claimed this former magnificent buffalo-elk range and fired the prairie to once more rid it of the woody scurge that would deplete it’s forage resource. Cowboy meaning: a roaring up-slope fire “did in” the blasted damn blackjacks and let the grass get the upper hand.

This and the next slide showed beginning— and perhaps not so beginning —students of Range Management how effective prescribed burning can be in maintaining grasslands and savannahs against excessive woody encroachments. Even though these two photographs were of neighboring tallgrass prairie vegetation and are not technically speaking that of Cross Timbers, they illustrated perfectly how fire maintains the “balance” (proper proportions) between woody and herbaceous climax species in the potential natural vegetation of savannas like the Cross Timbers that are neighbors to some of God’s greatest fire-maintained grasslands.

14.  Blackjack oak trees top-killed on bluestem prairie by prescribed burning- A hot heading fire about six weeks prior to this photograph was used to completely top-kill blackjack oaks that invaded virgin big bluestem-dominated prairie from neighboring Cross Timbers. The bluestem pasture was fired when the blackjacks and grasses were dormant. The typical stimulus-like response of big bluestem and Indiangrass to spring burning was evident in this post-burn view, but the blackjacks also responded with immediate resprounting from stumps and roots. Yes it would take more than one intense “hotter ‘n hell” fire to rid this luxuriant range of the invading blackjack oak, but one fire effectively killed or eliminated what was surely two decades or more of oak growth. Prescribed fire but once in four or five years will control blackjack oak to its proportion of species composition in the climax grassland (ie. reduce oak crown cover to levels approximating those of the potential natural vegetation), and make more grass forage for buffalo, elk, beef cattle, etc.and more meat for top-order carnivores such as man.

Note height of sprouts of both blackjack oak and smooth sumac (the latter along extreme right margin of slide). Observe also the absence of grass under blackjacks in pronounced circular patterns. This latter phenomenon can be extrapolated back to the pattern observed above for the blackjack shrub thickets on south slopes in the Sandstone Hills Cross Timbers (three slides immediately above this slide).

15. The Texas West Cross Timbers- This is the brush or thicket form of the Cross Timbers. It is the kind that Washington Irving must have had to pass through when he described the Cross Timbers as “forest of cast iron”.  It is the “vegetal type” named and described by Dyksterhuis (1948) as the “Quercus-Smilax type” on sandy Red and Yellow Podzolic soils of gentle to moderate slope. Dyksterhuis (1948, p. 341) found the mostcommon grass to be fringeleaf paspalum (Paspalum ciliatifolium). In this parcel sand dropseed (Sporobolus cryptandrus) was the clear dominant grass, but silver and little bluestem, sideoats and hairy grama, common grassbur (Cenchrus incertus), tumblegrass (Schedonnardus paniculatus), purpletop, Johnsongrass (Sorghum halepense), and tumble windmillgrass (Chloris verticillata) were all common (and most are visible in the slide). Saw greenbriar (Smilax bonanox) is clearly the dominant shrub (not the place for a trail ride) followed by the associate shrub, smooth sumac (Rhus glabra), and scattered chittamwood or gum-elastic (Bumelia lanuginosa). Tree species in order of dominance: post oak and blackjack oak (dominants), live oak (an infrequent associate), and mesquite (rare).   

As a University of Nebraska-produced Ph. D. (a student of John E. Weaver and disciple of F.E. Clements) E.J. Dyksterhuis (1948, ps. 372-374) generally regarded the potential vegetation of the Westerrn Cross Timbers as a climatic climax of oak-little bluestem and Indiangrass understory savannah. That form was shown in some of the preceding slides. Dyksterhuis was unsure how to interprete the Cross Timbers vegetation on Red and Yellow Podzolic soils (p. 373). It seemed logical (rather undeniable in fact) to the current author that such vegetation was a mixed understory of shrubs and grasses (tall, mid- and short grasses) with a woodland-like canopy of scattered oaks of smaller mature size than those of grassland savannas. This seemed the only rational explanation given that the Cross Timbers oak scrub type known as Sand Rough (see under Shrubland slides) exist as postclimax at one extreme of dominance by woody species while the woodland form of savanna exist at the extreme of least coverage of woody plants. Furthermore this must be combined with the historic accounts of tangled woody undergrowth prior to overgrazing by livestock (ie. in the virgin vegetation).

16. Forest form of Western Cross Timbers (Texas)- Exterior view of the forest-like expression of post oak-dominated Western Cross Timbers. These large post oaks have a well-developed tree-form resulting in a physiogonomy and architecture that resembled an actual forest or, at least, a woodland rather than the savanna form or physiogonomic expression more common of the Cross Timbers. Equally, if not more importantly, the trees were large (by post oak standards) and not distinguished by twisted and broken limbs. Trees with these features (ie. “normal trees”) stood in rather stark contrast to the stunted or more-or-less depauperate form of post and blackjack oaks that are thought of as more characteristic of old-growth specimens. In one of the earliest reports on the Cross Timbers of Oklahoma Bruner (1931) described described the trees as “… a scrubby growth of oaks…” (p. 142). Bruner (1931, p.146) presented a photograph of a stunted post oak and described it as “showing the typical growth-form in the savanna”. He wrote that on uplands post oak was “… always small or of moderate stature”. Dyksterhuis (1948, p.333) quoted from a report in 1841 that described the trees as “principally small gnarled” and Dyksterhuis (1948, p. 337) remarked that “timber of log-size “ was at time of his monograph restricted to flood plains. Diggs et al. (1999, ps. 46-48, Fig. 20, p. 49) and Francaviglia (2000, ps.38-40) described the general shape and dimunitive size of post and blackjack oaks.

The trees shown here were massive by Cross Timbers standards and were included to enable viewers to appreciate the size and age to which trees of this savanna type can grow. Viewers should take careful note of the relative great height at which limbs come off the bole. Dyksterhuis (1948, p. 333) wrote that the “oldest ranchers” he spoke with recalled that fires in the tallgrass understory of Cross Timbers “burned the limbs off the trees to a height that enabled a man on horseback to ride beneath their crowns”. Viewers could also note to advantage the horizonal orientation of limbs (and even secondary branches) on these ancient post oaks. Such morphological features clearly indicated the absence of a competing woody understory throughout most of the long lives of these patriarchs. Recent fires have not run through this old stand of monarchs and a woody understory developed instead of the climax herbaceous understory dominated by little bluestem and Indiangrass. Most tragically, an understory of young Ashe or blueberry cedar has formed under the mighty post oaks due to the the “toilet habits’ of birds that perched in the canopy and fire exclusion practices (or the neglect of prescribed burning) of contemporary agricultural man. Blueberry juniper is a nonsprouting species. In the days before man, and later when the red man had the Cross Timbers to himself, natural fires and/or those set in aboriginal wisdom would have taken proper care of the bloody invading blueberry. Now this coniferous pest can grow to heights that will form a fire staircase and generate such intense heat as to threaten the robust and ancient post oaks.  

The species present in this outer or physiogonomic view were given immediately below with the next slide which is an “inside look” at this same local community.

17. Interior of the forest form of Western Cross Timbers (Texas)- A view inside the post oak- dominated forest form of the Western Cross Timbers. Cedar elm (Ulmus crassifolia) was the associate tree species with red mulberry (Morus rubra) running a “close second”. Some sugarberry (Celtis laevigata) was also present. Blackjack oak was absent from this local community, but there were occasional (scattered) large specimens of Texas red oak, also known variously as Shumard or Spanish oak, (Quercus shumardii). Dominant understory shrub was Carolina buckthorn or Indian cherry (Rhamnus caroliniana), but in some areas red haw (Viburnum rufidulum) was locally dominant. (The shrub with the extremely crooked trunk at far right foreground is a red haw.) Green briar or, variously catbriar or bullbriar, (Smilax bonanox) formed a layer with leaves extending both below the trunk and above the crown of the Carolina buckthorn, but the latter appeared to exceed the former in cover. Other shrub species included poison oak, redbud, smooth sumac, skunkbush sumac, spring herald, known also as elbow-bush or devil’s elbow, (Forestiera pubescens), and chittimwood (Bumelia lanuginose), but these were restricted primarily to edges where Cross Timbers came into contact with the interspersed mosaic of Grand Prairie tallgrass prairie and small openings in the Cross Timbers. Community. Shade from the unnaturally high rate of regeneration of oak, elm, mulberry, and, sometimes even, sugarberry plus greenbriar, buckthorn, and red haw had effectively excluded all but relicts of the climax tallgrass. The dominant tallgrass climax species was little bluestem with Indiangrass, upland switchgrass, and big bluestem the other decreasers that occurred (in approximately that order). Some Canada or nodding wildrye, another decreaser, was present. The most common grass was purpletop, an increaser. Grasses were most common on small local areas in association with shrubs, especially where shrub cover was sparse. Forbs were not common, but the perennial herbaceous species known variously as Louisiana (or Mexican or white) sagebrush or western mugwort (Artemisia ludoviciana var. mexicana) was the major one.

Dykesterhuis (1948, ps. 342-343) characterized this as the Quercus-Smilax type of the Western Cross Timbers. This type with designation based on name of dominant Genus of the canopy and of the woody understorey (a Texas version of habitat type that preceeded that of Daubenmire perhaps?) was not adequate by itself to communicate this community. The same designation also described the vegetative or physiogonomic character of the scrub form (the thicket or the tangle) of Cross Timbers that was shown and discussed earlier. The composition (species make-up, physiogonomy, layering etc.) of this forest form differed substantially from the previously shown and discussed oak-greenbriar subtype. Most importantly, buckthorn and red haw were absent from the scrub or thicket form shown above. Perhaps most diagnostic among differences was that the Texas red (=Spanish or Shumard) oak was a shrub (at best a small tree) form with short stature and multi-trunk morphology in the thicket or tangle form whereas here in the forest form or subtype of Cross Timbers Shumard oak grew in a tree form sometimes exceeding the large post oaks in stature and trunk diameter. For example, the large tree with tall forked bole in right background was a Shumard oak. The oak-greenbriar thicket  (scrub) subtype or form had much greater species diversity and development of tree, shrub, and herbaceous layers.

18. Detail view of interior of post oak-dominated forest form or subtype of Western Cross Timbers (Texas)- This photograph showed detail of the local Cross Timbers community shown in the two preceding slides. The two large trees in foreground (left with straight bole and right with large limbs diverging from bole) were post oaks. The two small trees with light-colored bark immediately behind but to right of the widely branching big post oak were red mulberry. The larger background tree on left was post oak and the two smaller trees immediately to right of it were cedar elm. Local understory was all woody and comprised mostly of greenbriar. None of the climax tallgrass understory species were visible within camera range of this photograph, but some shade-stunted specimens of such species as little bluestem, Canada wildrye, Indiangrass, and purpletop were present in this local community.   

19. Cross Timbers and Barrens- Landscape scale view of Western (Upper) Cross Timbers existing as a "patchwork" pattern of woodland and glades or balds. The Cross Timbers and adjacent prairies (delineated variously into such units as Fort Worth, Grand, and Northcentral Prairies) are typically interspersed into a mosaic of vegetation varying from open tallgrass prairie to dense oak-hickory (black hickory and pecan) forests with a savanna form made up of these two extremes plus an open, grassy understory woodland between. A much less common form or expression of vegetation in this "botanical mixture" consist of small glades or balds occuring on hilltops with very shallow soils underlaid by the defining sandstone formations. These sandstone barrens are similar to the chert and dolomite glades interspersed among the oak-hickory forest and tallgrass prairies of the Ozark Plateau several hundred miles eastward (presented below in this Tallgrass Savanna section).

Vegetation shown here was photographed from one such sandstone glade with another such barrens visible in center background. Sandstone balds occurred as vegetational subunits within the overall Sandstone Hills range site presented here and in the following series of photographs taken in or adjacent to Lake Mineral Wells State Park. This was in one of the more distinctive areas of the Cross Timbers delineated by it's rugged, broken topography and exposed sandstone and shale rocks and identified as the "Palo Pinto Country" (Diggs et al, 1999, ps. 22, 45-46). Descriptions of vegetation accompanied those examples.

20. Canyon landform of Cross Timbers and Barrens- Vernal aspect (March) of the same vegetation at same precise location as shown in the immediately preceding photograph except from slightly different angle and at wider lense view. From this vantage point the canyonlands form of the "Palo Pinto Country" Cross Timbers was readily shown. The climax plant community of the "bald" (barrens) atop the characteristic sandstone excarpment in background was shown in detail below. In the present photograph the vegetational mosaic at landscape scale was evident. The view was from one sandstone block photographed across the canyon to another sandstone bloc, each the parent material and lithosol for the local "barrens" or "balds" range site (essentially a larger microsite) within general Sandstone Hills range site. Canyon bottom was a more mesic localized microhabitat favoring cedar elm and Texas ash over the dominant oak species.

The large sparsely foliated tree in center midground was cedar elm as was snag in left front of it. A large Texas ash was immediately to right of large cedar elm. Tree immediately right of Texas ash was also cedar elm. These two species were associates to post oak, the overall dominant species, and to blackjack oak, the dominant vascular plant on the "balds" (shown below).

25. Sandstone glade in Western Cross Timbers- The rugged terrain and harsh nature of the "Palo Pinto Country" West Cross Timbers included local sites (larger microsites) with soils that were somewhat better developed (apparently older) than the rock outcrops responsible for the sandstone barrens vegetation shown in the three immediately preceding photographs. Vegetation in this photograph was conterminus with the plant community (ies) seen in these preceding slides.

This vegetation was climax (in the virgin state) except for woody species that were invading due to absence of fire (fire suppression) on this Texas state park. Fire was a natural component of the climate that contributed greatly to development and maintenance of the Cross Timbers. Woody invaders in this photograph included chittamwood, gum-elastic, or gum bumelia (Bumelia lanuginosa); greenbriar; netleaf hackberry or sugarberry (Celtis reticulata= C. laevigata var. reticulata), redberry cedar or redberry juniper (Juniperus pinchotii); and blueberry cedar or ash juniper (J. ashei). Dominant herbaceous species were little bluestem, sideoats grama, and purpletop. Both woody and gramineous species are native and part of the climax or potential natural vegetation, but the unnatural increase of shrubs and trees was obviously primarily a result of elimination (at least great reduction) of natural fire regimes. Presence (and relatively large populations) of climax dominants (decreasers like little bluestem) coupled with absence of any appreciable component of herbaceous invaders (eg. purple threeawn) or hardly even increasers (eg. purple dropseed) was evidence against current, or even recent, overgrazing. Nonetheless, abnormal increase (invasion) by woody plants was causing on-going range retrogression. Underburning was a principal cause of range depletion.

Parker County, Texas. March (vernal aspect).

Next slide, please.

26. Overgrazed sandstone glade- The vegetation shown here was on private property contiguous with that seen in the immediately preceding photograph. The plant community seen in this slide was being (or had very recently been) overgrazed. Prolonged or longterm overuse had resulted in depletion of the more palatable little bluestem, purpletop, and sideoats grama and commensurate invasion by purple threeawn (the conspicuous tufts of bunchgrass) and increases in purpleflower droopseed (predominate plant among clumps of threeawn).

Invasion of the same woody species as in the preceding slide was evident along edges of the glade as an advancing line of young shrubs that was reducing the area of the herbaceous plant community. Fire cessation was also a factor in this invasion, but in addition to underburning overgrazing was an agent of retrogression that induced range depletion in this instance.

Parker County, Texas. March (vernal aspect).

27. Climax sandstone glade in Western Cross Timbers- Two views of a sandstone glade in excellent range condition situated among adjacent tracts of blackjack oak-dominated woodland characteristic of Western (Upper) Cross Timbers. This vegetation was on a hilltop portion of Cross Timbers having more of an open woodland physiogonomy that had a "tangled" understorey consisting of a woody layer of shrubs dominated by young (immature) blackjack and also including young post oak, cedar elm, sugarberry or netleaf hackberry, and such shurb species as saw greenbriar, winged sumac (Rhus copallinum var latifolia), skunkbush sumac, and chittamwood, and an herbaceous layer dominated by little bluestem.

Woody species were noticably less abundant than on adjacent glades shown above including the one that had been been subjected to recent or current overgrazing.

Parts of the sandstone balds or barrens were devoid of woody species (especially the glade form) and had a more species-rich herbaceous community. Little bluestem was the most abundant species but there was not an apparent dominant. The other common grass species on the balds were: green sprangletop (Leptochloa dubia), sand lovegrass (Eragrostis trichoides), and sideoats grama on the shallower microsites in central portions of the glade and tall dropseed (Sporbolus asper) , Texas wintergrass (Stipa leucotricha), purpletop, Scribner's panicgrass (Panicum scribnerianum), Canada wildrye, and wood oats (Uniola latifolia= Chasmanthium latifolium) along perimeter of the glade and beneath or otherwise in shade of trees. The conspicuously dominant forb was slender bushpea or slender lespedeza (Lespedeza virginica).

28. Shown below was a series of photographs of Western Cross Timbers in relict or near relict climax condition. The sequence began with an exterior view and consecutive photographs showed progressively more interior views of relatively undisturbed old growth Cross Timbers vegetation. Exclusion of fire by policy and action of a state government agency allowed unnatural excessive development of woody species in the understorey with concomittant decline in the herbaceous component (primarily of little bluestem, the dominant, and also of other grasses such as purpletop, the associate herbceous species, sideoats grama, wood oats, tall dropseed, Canada or nodding wildrye, Texas wintergrass, and even small amounts of big bluestem and Indiangrass).

Composite view of Western Cross Timbers community- An exterior perspective of a virgin stand of post oak-dominated Cross Timbers with a rich diversity of species in all vegetational layers. The foreground was edge of a small opening or glade dominated by little bluestem accompanied by purpletop, wood oats, tall dropseed, Scribner's panicgrass, with traces of big bluestem and Indiangrass in lower (more mesic) microsites at far right foreground. Englemann or Lindheimer (sometimes Texas or nopal) pricklypear (Opuntia engelmannii var. lindheimeri) was conspicuous in the glade (left-center foreground). Most apparent forb was goldenrod (Solidago sp). The young tree or shrub appearing as a bush at far left foreground was blackjack oak showing regeneration of this climax species and illustrating fact that blackjack not post oak tends to dominate on the shallower soil of glades. The large tree with brightly colored leaves at right forefront of tree edge was Texas ash (Fraxinus texensis= F. americana var. texensis). The most common shrub in understorey beneath trees was saw greenbriar. October, but still estival aspect.

Stand of old growth post oak-dominated West Cross Timbers- On this sandstone rock outcrop the habit of mature (nearly ancient in relative terms) post oaks created the physiogonomy characteristic of the climax forest form of Cross Timbers. This was an example of the Quercus-Smilax type of the Main Belt described by Dyksterhuis (1948, ps. 340-342). The conspicuous rounded shrub in center foregrounmd was elbow-bush, devil's-elbow, or spring-herald which is typically more common on calecareous soils and among limestone more than sandstone outcrops. Englemann pricklypear was also conspicuously growing at edge of forest and a grass-dominated glade. The understorey inside the forest itlself (beneath trees and not natural clearing or glade) was primarily regenerating post oak and saw greenbriar. Grass species visible at edge of forest and glade (center foreground) was silver bluestem. October, but still estival aspect.

Interior of old growth West Cross Timbers forest community- It was noted at beginning of the Cross Timbers section that this forest or range type was primarily a savanna, but that vegetation was a continuum which varied from grassland with widely scattered (isolated) trees to dense forest and with intermediate types of such canopy cover as to form woodland and savanna forms of the general Cross Timbers cover type. The photographs included in this present series illustrated the forest form. Post oak was the dominant form with blackjack the clear associate. In this slide blackjack was represented by the the second tree trunk from the right and the smaller trunk at far left (leftmost tree). The pronounced horizonal branching of trees that grew in more open woodland was prominent in the limbs of the largest tree, a post oak, in center of slide. The pronounced outward (toward light) curving of the bole (bow-shaped trunk) of the blackjack was another common growth mainifestation of old- growth oaks (in woodland and even savanna forms as well as in forest canopy cover forms).

The understorey was almost exclusively post and some blackjack oak reproduction. Oak leaves formed a forest floor covering interrupted only by standstone rocks. There was essentially no herbaceous undergrowth. Saw breenbriar was sparse and limited to small areas where light could penetrate through the oak canopy to reach the ground surface. Rarely there were other species of woody vines as shown and described in the succeeding photograph and caption.

Lichens growing on the outcropping sandstone rocks formed a layer of vegetation that students should not overlook.

Estival aspect into early October.

Deep inside a Cross Timbers forest on a sandstone outcrop- Narrow spaces of soil among huge sandstone boulders (as large as small houses) provided favorable environments for growth of Cross Timbers trees. Post and blackjack oaks were dominant, but sugarberry or hackberry, Texas ash, and cedar elm were also common. Climbing species were, as shown here, abundant. The thicket-like growth in the left foreground was a mixture of saw greenbriar, supplejack or rattanvine (Berchemia scandens), and poison ivy or oak. Other common vines found variously in the boulder location were Carolina snailseed (Coccus carolinus), Virginia creeper, trumpet-creeper (Campsis radicans), and, infrequently, mustang grape (Vitis mustangensis). This boulder form or expression of a Sandstone Hills range site had so much shade from tree canopies and the vertical rock formation that herbaceous species were more-or-less absent.

October, but still estival aspect.

Not enough fire- Most of the early explorer accounts of the Cross Timbers (including the poetic account of Irving [1835, p. 186] quoted above) and the seminal ecological studies (eg the monograph of Dyksterhuis [1948, p. 333] also cited previously) specifically described presence and/or role of fire in understorey of the Cross Timbers.Fire had obviously been excluded and suppressed-- and obviously for a long time period-- from the state park in which these photographs were taken. Long-term absence of fire, a natural environmental factor, from this Cross Timbers vegetation had allower development of an unnaturally dense woody understorey which had eliminated most of the native herbaceous species except for small microsites. An excample of one such microhabitat was that shown here around an older post oak. Little bluestem, the dominant herb and co-dominant Cross Timbers species (with co-dominant post oak), had persisted on this local site (and others like it). Even here brush (woody species present at unnaturally excesssive cover and population densities) were encroaching on the limited remaining microsites that afforded adequate sunlight and growing spaces. Most of the woody (and excessive) understorey was of post and blackjack oak, but other tree and shrub species were also present. Chief among these was saw greenbriar and chittamwood or bumelia.

General co-dominants of the Cross Timbers- Post oak (larger tree with twisted limbs at left background) and blackjack oak ("runt"-- as in scrubby-- trees at right) are the general two dominants of the Cross Timbers. Post oak is far and away the clear dominant with blackjack subordinate so as to be more of an associate, except that blackjack-- often as shrub or small tree more than true arboreus form-- is the exclusnve dominant on the more xeric sites and microsites such as the balds or barrens form of Crosss Timbers.

The shrub layer of Cross Timbers understorey was conspicuous in this photograph due to showy full-bloom phenological stage of creek or hog plum (Prunus rivularis). The two oak species were also in anthesis.

Western Cross Timbers in the spring- Thickets of blooming hog or creek plum highlighted the shrub layer of an understorey beneath the dominant species of post oak (tree with the sparse foliage of new leaves and catkins in right background) and blackjack oak (largest tree in center foreground and branches at far left foreground. Chittamwood or gum-elastic and Carolina buckthorn (Rhamnus caroliniana) were also present as understorey shrubs.

29. One of the key distinguishing (and picutresque) features of the Cross Timbers is the unusual and interesting shape of boles, limbs and branches, crowns, and overall habit or growth form of individual trees of the dominant post and blackjack oaks. These characteristics of distorted tree growth distinguish-- even at first or fleeting glance-- the Cross Timbers expression of the general oak-hickory association or, more precisely, the ecotone between this climax forest type and the tallgrass prairie climax type from the westernmost extension of the actual oak-hickory forest region of Braun (1950, pgs. 35, 162-191). This ultimate authority on the eastern deciduous forest included the Cross Timbers as one part of the "forest-prairie transition" in the oak-hickory region and described the oaks as "usually small and scrubby with broad low crowns" (Braun, 1950, pgs 177-178).

Many, if not most, descriptions of the Cross Timbers characterized the post and blackjack oaks variously as "stunted", "scrubby" or "scrubs", "dwarfish" or "dwarfs", "diminutive", "small-sized", "undersized" "depauperate", etc. More recently-- and perhaps as result of interest in old-growth forests and individual old-growth specimens-- descriptions of relatively small mature trees were more detailed as to specific aspects or parts of small-size and apparent "stunted growth" morphology. From dendroclimatic studies such unique tree habits, crowns, trunk and limb shapes, etc. have been related to harsh physical and chemical features of tree habitat on which slow plant growth rates and distorted tree organs (due perhaps to injury) were associated with old age. Perhaps old age and "abnormal" appearance of trees were results of poor growing conditions such as undernutrition or near constant edaphic drought. Distorted shape and size of organs like boles and limbs might reflect conditions that were below optimum for "normal" growth and reproduction but near maximum for longevity.) Cause and effect relations among the factors of tree age, tree growth, soil conditions, climate (including lightening and fire), browsing, and so forth are not adquately understood.

Diggs et al. (1999, p. 47) described this phenomenon of misshapen, often grotesque, form and diminutive size of old-growth or "ancient" individual trees in the Cross Timbers. These authors cited findings from dendrochronology (tree-ring analysis) and summarized as follows: "Because of the low availability of moisture, rocky or infertile soil, and other factors, the trees of these relict forests, while old, have a slow rate of growth and are of relatively small size... Such old-growth forests or ancient individual trrees can often be located by environmental factors such as steep, rocky, infertile soils or by the appearance of the individual trees... Twisted stems, dead tops and branches, canopies restricted to a few heavy limbs, branch stubs, fire and lightening scars, leaning stems, exposed roots or root collars, and hollow voids are all hints of significtnt age".

Shown below were examples of mature and, quite likely, old if not "ancient" trees growing in the harsh environment of the rugged "Palo Pinto Country" Cross Timbers. Some of these trees had "real character" possessing distinguishing "marks" that obviously resulted from injury (eg. crowns whose tops had been torn off by wind or blown off by lightening, hollows due to rotting following such "amputation", fire scars). Other unusual shapes and sizes appeared to be more the result of inadequate/improper nutrition, including sufficient water.

Readers should bear in mind that this phenomenon of natural bonsai-like growth and aging is not limited to oaks in the Cross Timbers nor to oaks. As shown elsewhere in this publication, dead tops with hollows, spires, cavities and limb loss due to fire or other forces, and relatively small size are characteristics common to old-growth Juniperus trees on pinon-juniper woodland. Neither are such features that are frequent on old trees limited to environments unfavorable for tree growth and survival. Many of the very large (and very old) individuals of the various conifer species that grew to record size, shape, and dimensions (ie. "record", meaning "brag", trees) live on the most favorable, productive sites. The coast redwoods with spire-like dead tops and "goose pen" fire and wind scars are probably most notable among these, but many other examples exist among Sitka spruce, western hemlock, western red cedar, Douglas fir, and even ponderosa pine. It appeared that such scars and marks likely are results of a long life more more than of a hard life.

Whatever the cause-effect relations, many of the Cross Timbers post and blackjack oaks sport natural mutulations that should be the envy of any human specimens vainly flashing tatoos, pierced body parts, streatched necks, embalmed breasts, plasticized penises, corseted abdomens, bustled buttocks, and once-healthy skin now sun-scorched or "fake-baked" to the state of weathered saddle leather or a cancer-eyed cow. The difference between a deformed, hollow old tree and a woman with diamond studs in peirced ears is that the tree has a beauty and dignity all its own. The woman just looks like she was shot with rock salt. Enjoy the examples.

Arborescent goblins- A branching pattern in which primary limbs radiated horizonally from the short trunk with secondary and vertical branching from the primaries gave a hominoid-like appearance to these old Cross Timbers post oaks. Such trees give even the most hardened coon hunter an almost erie feeling as he tromps through these woods under a full moon. One can imagine the spell-like feeling cast on backwoodsmen upon first setting foot in these vast primival savannas.

The featured post oak had lost it's central shoot, including the apically domiant terminal meristem, so that once released from apical dominance secondary branches on the primary limbs grew and developed in neraly vertical planes. The smaller tree with glossy green leaves to left of ole Lost Top was a younger blackjack oak. A young Texas ash was at right base of the topped post oak. Widely scattered shrubs included greenbriar, elbow bush (Foresteria pubescens var. glabrifolia), skunkbush sumac, chittamwood, and Carolina buckthorn. Grasses were absent apparently having been mulched out by accumulations of leaves from the dominant oaks and understorey shrubs as result of unnatural fire exclusion.

"And the gobble-uns'll git ya ef ya Don't Watch Out."--- Little Orphant Annie, James Whitcomb Riley

March: vernal aspect with oaks in full-flower.

Crown development of an old post oak subsequent to death of the central and dominant shoot- For a reason (perhaps injury due to lightening, wind, insects, disease) known but to God the main leader of this post oak died such that relieved from dominance (suppression) by apical meristem lower subordinate limbs and branches developed. Result was a lop-sided crown and another hollow-top tree serving as a cozy den for some varmit like a coon or 'possum. Some such tree become hollow clear to the base of their trunk as the innermost trunk, especially heartwood, rots out. This does not affect living tissue (such central heartwood and older sapwood are dead anyway) nor does it typically affect tree health. Such rotting may eventually contribute to loss of tree rigidity and even tree blow-over if and when decomposition proceeds to the root system, but more commonly impact is neglible.

The reason is a feature of physics that is widely know among mechanical engineers: hollow tubes like bird quills, most grass shoot internodes, pipes, airplane wings, and hollow trees are almost as strong as a solid piece of wood, metal, or feather. And they are much less lighter which allows resources to be used for other tissues or materials (eg. those capable of conducting photsynthesis or holding jet fuel) or for more efficient work (easier and more economical to clear ground or a tree branch for flight). It would even be desirable to construct hollow railroad ties, but the technology to do such does not justify the savings in wood.

The well-developed shrub layer of the understorey was comprised mostly of skunkbush sumac and elbow bush with lesser cover of greenbriar.

March: vernal aspect, full bloom phenological stage in oaks.

Wooden arm with a dozen elbows: growth and branching pattern of post oak on sandstone bald- This microhabitat on an outcropping of sandstone was marginal even for a post oak. Result was that this speciman developed a recurrent geniculate (a back-and-forth bending) shape to it's trunk and branches. The more xeric (or less mesic) blackjack oak is typically dominant on such microsites with their shallower, drier soil. Such was the case seen here where scrub (shrub form) blackjacks surrounded the bent, knarled old post oak. These appeared to enjoy each other's company, but they obviously did not invite any herbaceous species to join their party.

Vernal aspect (March, and under a grand but equally rare cobalt-blue Texas sky).

What tales this ole devil tells- An ancient post oak lost the upper portion of it's trunk complete with crown except for one limb which subsequently sent up a vertical branch to assume role of former main shoot and crown though in a much reduced capacity. Yet another picturesque example of the phenomenon of apical dominance. This magnificent old tree was a real survivor-- complete with sexual reproduction and passing on of it's genes in propaguling acorns . In addition to serving as prime real estate for den-dwelling furbearers this gnarled, weatherbeaten, ranking member of the Cross Timbers community never tires of talking about it's accident or "operation". A passing rangeman paused to record the story and pass it along to fellow students of vegetation and admirers of things beautiful.

Palo Pinto County, Texas. March: vernal aspect.

Breakage in the Oklahoma Cross Timbers- Stand of Cross Timbers dominated by post and blackjack oak in Sandstone Hills of northern Oklahoma shortly after a severe to extreme ice storm from a winter mix of precipitation caused widespread and locally extradinary damage to trees and shrubs. Damage to trees ranged from loss of minor twigs to uprooting with most trees suffering heavy damage with loss of some major limbs total crown loss.

The beneficiaries of such devestation were the understorey species especially the tallgrass species like little bluestem and Indiangrass on this west slope.

Lincoln County, Oklahoma. Mid-December.

Chewed up by ice- Young blackjack oak (first or upper slide) and ancient post oak (second or lower slide) in Sandstone Hills Cross Timbers with extreme ice damage from a late autumn winter storm that brought rain, freezing rain, sleet, and snow which built up to such accumulations (depths of one to four inches) of ice on trees that limbs, large to small branches, and twigs were broken. Some trees like this old post oak (and the ancient post oak presented immediately below) were completely topped with their crowns more broken than Jack when he fell down. Some trees were even toppled by uprooting from heavy ice accumulations.

When rangemen and foresters speak of agents of defoliation the consideration is not limited to grazing/browsing animals. "Fire and ice" along with wind, frost, drought and others keep the Cross Timbers far from being a Garden of Eden, at least from a tree's vantage point. Incidentially, all this ice-downed wood is fuel just waiting for a fire that could be readily ignited by spring thunderstorms that undoubtedly await these survivors. And you thought you had it rough!

Lincoln County, Oklahoma. Mid-December.

"Gittin' old ain't for sissies"- This grand ole patriarch was not favored to live all its "golden years" as "happy times". This ancient specimen was hit by a severe or extreme ice storm a week before these two photographs recorded the tragic event in its long life. A late autumn (9 December, 2007) ice storm (a winter mix of rain, freezing rain, sleet, and snow) struck the Cross Timbers in the Sandstone Hills or northern Oklahoma with the devestation of a twister. This ice storm was due to the phenomenon of overriding, the atmospheric condition that results from the meeting (a collusion) when warm, moist air from the Gulf of Mexico and a cold Arctic air mass (a Norther). The accumulation of ice (up to several inches thick) wrought damage to trees varying from loss of small branches to major limbs to, as in this case, the complete topping of a large tree.

And this might not be the end of the tragedy. The heavy accumulation of downed timber is fuel-loading just waiting for a fire that could be sparked readily from spring thunderstorms ( which in Oklahoma are more numerous and every bit as notarious as ice storms). This senior citizen of the Cross Timbers does not seem destined to meet a mild end to its old life, but stay tuned as we follow its saga.

Lincoln County, Oklahoma. Mid-December.

31. Post oak- Young leaves and catkins of the dominant tree species of the Post Oak Savanna and Cross Timbers of Texas and most of the Cross Timbers Oklahoma into Kansas except on sites dominated by

32. Leaves and fruit of post oak (Quercus stellata)- Characteristic apex of short shoot of post oak showing typical arrangement of an extra heavy crop of acorns. Post oak is a member of the Quercus subgenus Leucobalanus, the white oaks, whose leaf veins do not extend as spines, bristles, or "teeth" beyond leaf margins. Leucobalanus species bear fruit annually (ie. acorns mature in the same growing season) so that acorns are borne on current-season shoots (leaders). The kernal or "meat" of acorns in the white oak subgenus are sweet-tasting (versus the bitter kernals of red or black oaks). Erath County, Texas. October.

33. Post oak acorns- Detail of cup and nut of post oak acorns. Erath County, Texas. September.

35. Normal appearance of leaves and acorn on a leader of blackjack oak- Blackjack is a member of Quercus subgenus Erythrobalanus (red or black oaks) one characteristic of which is extensions of veins or ribs of leaves beyon the margin so as to appear as spines, bristles, opr "teeth". Acorns of Erythrobalanus oaks require two growing seasons for development and maturation. Thus these fruits are borne on twigs (leaders) that were produced during the previous growing season. Meat of the acorn is bitter or tart-tasting. Erath County, Texas. October.

36. Blackjack (Quercus marilandica) branch-Lateral shoot of blackjack oak with leaves and fully mature fruit. Erath County, Texas. October.

37. Leaves and acorn (at full maturity) of blackjack oak- Detail of ripe acorn and two leaves of blackjack oak. Erath County, Texas. October.

38. Texas ash tree (Fraxinus texensis= F. americana subsp. texensis) in spring uniform- This ash was the one featured above in photographs that showed a composite of the Western Cross Timbers old-growth community. This tree was in the immediate pre-bloom phenological stage and with the bright, glossy, young leaves that are characteristic of deciduous species in the Cross Timbers during spring before months of hot Texas sun turns them a dark forest green.

39. Shrub form of Texas ash- Multiple-boles (shoots or trunks) and relatively small stature of this Texas ash qualified it as a example of the shrub form of this species. This and the preceding photograph provided instructive examples of the distinction-- and often an arbitrary one-- between tree and shrub, a beginning lesson for students in the Principles & Practices of Range Management course. Learn the lesson.

42. Glossy new leaves of cedar elm (Ulmus crassifolia)- A branch and spring leaves of this Cross Timbers associate species had the shinny, waxy coat of newly expanded foliage that is characteristic of Texas trees and shrubs before the brutal heat of a long, baking summer takes it's toll.

43. Dogwood of the Cross Timbers- Roughleaf or Drummond's dogwood (Cornus drummondii) is a widely distributed "kissin' cousin" of the better-known flowering dogwood (C. florida). Roughleaf dogwood has much smaller flowers (shown below) and is better adapted to harsher habitats than its more mesic and florally endowed "cousin". For example, roughleaf dogwood is native to roughly the eastern half of the Lone Star Star so as to grow far west of flowering dogwood. Roughleaf dogwood is the Cornus species that is common in the Cross Timbers and Prairies vegetational area of Texas as well as northward through central Oklahoma and as far north as South Dakota. This is also the most widely distributed dogwood throughout the both the tallgrass and mixed prairies of the Central Lowlands physiographic province (McGregor et al., 1977, ps. 204-205).

Roughleaf dogwood was introduced as an important and common shrub on moister environments of the central grasslands of North America, understorey woody plant in Cross Timbers and local bottomland forest communities, and member of savannahs and general ecotones among grassland and forest range types. Roughleaf dogwood is also an major species in local postclimax communities within more general and larger range plant communities (macro-communities) as for example sandrough scrub in the West Cross Timbers.

The pretty specimen shown here was adding beauty to the understorey of a stand of post oak-dominated West Cross Timbers. Erath County, Texas. Late May. Full-bloom phenological stage.

44. A pack of dogwood flowers- Flower cluster of roughleaf dogwood. These examples were from a sandrough range type, a deep sand habitat existing as postclimax (monoclimax theory) or edaphic climax (polyclimax theory) with the greater West Cross Timbers.

Erath County, Texas. April.

46. Buckthorn or Carolina buckthorn (Rhamnus caroliniana= Frangula caroliniana)- Ths shrub is a distinctive understorey species of the Cross Timbers. Cross Timbers vegetation is, of course, the western-most extension of the oak-hickory forest. It was assigned to the Oak-Hickory Forest Region as a forest-prairie trnaistion by Braun (1950, p. 177). Carolina buckthorn appears to have an ecological niche and role in the Crosss Timbers similar to that of redbud and flowering dogwood in the main body of the oak-hickory forest types. Braun (1950, p. 153) listed R. caroliniana as being associated with redbud, dogwood, common persimmon, southern buckthorn (Bumelia lycioides), and skunkbush sumac on more xeric sites in the Western Mesophytic Forest Region. In his classic description of the Western Cross Timbers (Dyksterhuis (1948, Table 2, p. 341 and Table 3, p. 342) listed skunkbush sumac and false or wooly buckthorn, chittamwood or chittam, gum bumelia, gum elastic (Bumelia lanuginosa), but strangely did not list or even make passing reference to Carolina buckthorn.

47. Leader with leaves and fruit of Carolina buckthorn- The drupes of this species turn a bluish black at maturity. The fruitsin these examples were in the pinkish-red, pre-mature stage (and that is sometimes as far as they progress before birds, squirrels, and other wildlife species facilitate a pre-mature harvest.

Leaves of this species like many of the others of the Rhamnaceae (as well as Magnoliaceae) can be described as broad sclerophyll.

48. Rattanvine or Alabama supplejack (Berchemia scandens)- This liana (woody vine) is another member of the Rhamnaceae that is common in the Cross Timbers (and eastward into the Pineywoods portion of the eastern deciduous forest types). Supplejack grows in assocaition with other woody vines, especially various grapes (Vitis species) and greenbriar or catbriar (Smilax species). The specimen of rattanvine presented here was growing on an upper terrace of a pecan bottomland forest in a transition between Grand Prairie and Western Cross Timbers. (An example of Smilax bon-nox growing alongside this supplejack plant was presented below with another Smilax species.)

50. General view of portion of rattanvine or Alabama supplejack- A section of the shoot of this wood vine species showed new leaves and an unopened flower cluster on this winter-deciduous, perennial member of the buckthorn family. Supplejack is a widely distributed (and frrequently a major) species that grows upward through several layers of this savanna to woodland range type as well as in the Pineywoods.

51. Foliage and floral organs of Alabama supplejack- Two closer-in views of leaves and flower cluster in the specimen of rattanvine or supplejack introduced above. General leaf morphology as well as specific floral features in this species are remarkably similar to those of Carolina buckthorn, the plant species shown and discussed immediately prior to rattanvine (compare to above).

52. Thicket, hog, or creek plum (Prunus rivularis)- as indicated by one of it's common names this clonal shrub forms thickets (sometimes rather extensive ones) in the understorey of Cross Timbers (see photographs above). These expansive woody colonies provide both cover and feed for numerous species of wildlife. They are frequently a favored haunt for coveys of bobwhite quail as avid hunters of this marvelous upland game species attest. Hog plum (along with several other Prunus species of the Cross Timbers and Prairies area) also furnishes food for biped interlopers, especially in the form of delicious jam to complement homemade biscuits.

53. Young leaves and infloresences of thicket or hog plum- This Prunus species puts out it's new leaves and infloresecences simultaneously. There are few fragrances among native plants that are as potent yet pleasingly aromatic as those in the Prunus flower. This genus includes some of the native shrubs most favored by bona fide backwoodsmen. Prunus also includes some of the more important horticultural crops (to which prune-pickers readily accede).

54. Bur(r) or mossy cup oak (Quercus macrocarpa)- Young leaves and catkins of the dominant oak of the northern tallgrass, true, and mixed prairies northward from central Kansas. Bur oak can be interpreted as the northern ecological equivalent of post and blackjack oaks as   the aboreal dominant of the grassland-deciduous forest ecotone (Vankat, 1979, p. 221).  This species produces the largest acorns of any oak in North America and it is the oak of the famous oak groves and savannas of the northern grasslands (Peattie, 1938). Seedlings rapidly send their tap roots deep into the fertile prairie soils and become quickly established after germination (Weaver, 1968, ps. 135-139). This genetic adaptation to drought combined with the species’ thick fire resistant bark (Allen, 1967, p. 15) make it admirably suited to drought- and fire-prone prairies.

The species range of bur oak extends far south of its region of dominance into central Texas where it sometimes dominates bottomland savannas. Bur oak was placed at this point in the oak-hickory savannah to distinguish its region of dominance from that of post and blackjack oaks even though this specimen was growing as a minor component of the West Cross Timbers in Texas.Hamilton County, Texas, April.

55. Leaves and fruit of buroak- Burroak (either one or two "rs" are used) is regarded as having the largest acorn of any Quercus species in North America. Like other white oak species buroak bears fruit every year (versus a two-year cycle) in the red or black oaks. The combination of large acorns and production each year makes this species one of the most valuable producers of mast in the eastern deciduous forest (ie. the eastern part of North America).

Burroak is also known as mossy-cup oak, both common names in reference to the conspicuous tapered tips of the scales of the cup which present a fringe-like appearance. The geographic range of. Q. macrocarpa extends from eastern Canada (New Brunswick and Quebec) to Texas.

56. A Texas-size grape vine- Cross Timbers vegetation on more mesic habitats and that often develops into the forest or woodland (closed canopy) form of this savanna. This most complex or layer-rich structural expression of Cross Timbers sometimes includes a liana (woody training form) layer (a woody vine element that exends from the understorey to tree crowns). The most common woody vines or lianes in the Cross Timbers are various kinds of greenbriar (Smilax spp). Several of these Smilax species were included in the latter part of the Prairie Peninsula section below. Less frequently there are various grapes (Vitis spp.) that figure prominently in the architecture and botanical composition of the woodland subtype of Cross Timbers. These species "unite" lower and upper layers of the woodland subtypes of Cross Timbers.

57. Tumblegrass (Schedonnardus paniculatus)- This widespread eragrostoid grass (tribe of Chlorideae) is one of the more distinctive common (often locally abundant) components of the herbaceous understorey of Cross Timbers. Tumblegrass produces remarkably limited forage because much of its biomass is in that portion of its shoot comprising the long curving inflorescence. On most range sites tumblegrass is an invader.

58. Green sprangletop (Leptochloa dubia)- A drought-stressed but quickly recovering specimen of green sprangletop managed to flower and sexually reproduce its kind at base of a pecan in Western Cross Timbers. Green sprangletop is capable of a lot of phenotypic plasticity. This is true not only across the diversity of habitats on which this perennial species grows but also for the same plant from one year to the next depending on specific growing conditions on a given microenvironment (eg. drought one summer, flood the next spring, early onset of cool weather the following autumn). The plant shown here had just recovered (or was in process of recovering) from a severe drought that had extended from mid-spring to late-summer). This individual had succeeded in putting forth some small inflorescences on short (hardly extended) culms.

Green sprangletop is an increaser on Cross Timbers range, but it is also a good producer of forage having Fair feeding value.

Erath County, Texas. October, early bloom stage.

59. Young flowering shoots and inflorescences of green sprangletop- Late summer shoots of green sprangletop that developed following soaking rains after a severe summer drought These late-season shoots were either stunted (or would appear as such) because there was not enough growing season remaining to permit development to normal mature size of sexually reproductive shoots in this species. Photoperiod was certainly a major factor in this regard, though the phenomena of photoperiod interacted with drought stress.

Green sprangletop produces cleistogomous spikelets enveloped within sheaths of basal leaves (ie. in effect, still in the boot). Cleistogamy is the condition in which flowers do not open normally so that any fruit produced is through self-pollination and self-fertilization. Cleistogamy existed in green sprangletop shoots shown in both of these two photographs. A clone, clonal unit, or ramet of one (the same) green sprangletop plant was shown in each of these slides. On each clone there were very short shoots that remained encased within a folded sheath and unopened blade of a single leaf (ie. the boot). These were present at the base and in front of the more obvious stunted shoot that was bearing an emergent inflorescence. Within the boots of these extremely short shoots there were "hidden"-- meaning unexerted-- inflorescences. Again, these shortest shoots were in front of both stunted shoots that bore newly emergening or exerted inflorescences (one shoot with an opening inflorescence in each of these slides). These "hidden" inflorescences were retained within the boot and these unopened racemes were bearing cleistogomous spikelets. The tips of these cryptic inflorescences were barely visible (appearing as pubescence) from tip of the boot (= folded leaf).

Erath County, Texas. Understorey of Western Cross Timbers. September. Again, two forms of the flowering stage of phenological development: 1) inflorescence emerging from the boot and 2) nonemergent or unexerted inflorescence (retained within the boot) bearing cleistogamous flowers.

60. Anthesis in green sprangletop- The distal portion of a green sprangletop inflorescence, the racemes--with young florets and their exerted anthers--of which were spreading or extending away from the rachis. This stage of floral development was a day or two advanced beyond emergence of the inflorescence from the boots on separate shoots as presented in the two slides immediately above.

Erath County, Texas. Understorey of Western Cross Timbers. September, anthesis.

61. Green sprangletop (Leptochloa dubia)- Large single plant of green sprangletop with several sexual (floral) culms plus several inflorescences (right foreground) of a second plant that was "off-stage". On shallow, rocky range sites in semiarid parts of the Edwards Plateau green sprangletop is usually regarded as a decreaser as it typically declines rather quickly on such harsh sites with heavy grazing (and, of course, overgrazing). Green sprangletop grows in association with sideoats grama, Texas cupgrass, Texas wintergrass, and silver bluestem or pinhole bluestem on mixed prairie savanna rangeland in the semiarid Edwards Plateau.

Green sprangletop can grow to mature heights exceeding three feet. The individual shown in this photograph reached two and a half feet and thus was an example of the habit and size of the larger form of this species. Other individuals of green sprangletop are considerably shorter and smaller overall, especially under heavier grazing. This example was growing on the Excellent condition Edwards Plateau live oak-mixed prairie savanna range described above.

On many range sites, including some sites of semidesert grassland, green sprangletop is regarded as an increaser. On various of the shallower, more xeric range sites in the semiarid Edwards Plateau green sprangletop has a response more like that of a decreaser.

Gould (1975, p. 226) described this eragrostoid grass as being strictly cespitose with neither stolons nor rhizomes, buth Hatch and Pluhar, 1993, p.99) ascribed rhizomes to green sprangletop and Silveus (1933, p. 368) implied the same.

Edwards County, Texas. October, immediate post-peak standing crop at grain-shatter phenological stage.

62. Inflorescence of green sprangletop- An inflorescence on the large individual green sprangletop featured in the preceding photograph. The common name of sprangletop refers to the spreading--hence, "sprangled"--arrangement of the inflorescence. Generically speaking the inflorescence of this member of the Eragrostoideae subfamily consist of numerous racemes on primary branches directly off of the rachis.

Edwards County, Texas. October, grain-ripe to grain-shatter stage.

63. Lined sedge or eastern woodland caric sedge (Carex blanda)- One of the more common and widespread caric sedges in the Texas Cross Timbers. Although there are several species of Carex and Cyperus in the post oak-blackjack oak-pecan savanna designated Cross Timbers most of these are incidental and any abundance, let alone dominance, is local. Carex striatula is somewhat of an exception to this general rule. While any appreciable dominance by lined sedge is local, this species is common enough in distribution, especially in the Texas' West Cross Timbers, that it should be regarded, at least in part, as an important and defining/distinguishing) species.

In his monographic treatment of the West Cross Timbers vegetation Dyksterius (1948) did not list this Carex species. In fact he listed only one which is generally distributed more in eastern portions of the West Cross Timbers.

These plants were growing near base of a pecan.

Erath County, Texas. April.

64. Flowering in lined cric sedge- Sexual shoots of Carex blanda showing staminate and pistillate inflorescences at anthesis. These shoots were on the plants introduced in the immediately preceding photographs.

Erath County, Texas. April

The largest ecotone or transition zone between eastern deciduous forest and tallgrass prairie was the climax vegetation termed the Prairie Peninsula by Transeau (1935). This tallgrass and true prairie-deciduous forest ecotone in pre-Columbian North America was one of the largest savannahs on the continent. The Prairie Peninsula can, and frequently has been, interpreted as including the Cross Timbers as it southern- and western-most extensions. At most general or loose interpretation, however, the Cross Timbers can be interpreted as vegetational "islands" of the "mainland" peninsula of this deciduous forest-grassland ecotone. In a stricter sense the Prairie Peninsula was traditionally limited to more humid or, at least, more mesic soil conditions. Kuchler (1964, 1966) followed this convention. Kuchler (1964) designated an obviously more restricted Prairie Peninsula as Oak Savanna (unit 81) as distinguished from Cedar Galdes (unit 83) and Cross Timbers (unit 84). In USDA Forest Service Forest and Range Ecosytems (Garrison et al., 1977) the Kuchler (1966) map of potential natural vegetation distinguished within the Grassland and Forest Combinations between mapping unit of 73, Mosaic of units 66 (Bluestem Prairie) and 91 (Oak-Hickory Forest), and mapping unit 75, Cross Timbers. This traditional treatment was followed herein so that the Prairie Peninsula was dealt with below. Cedar Glades (which are balds or barrens rather than the similar and, perhaps, closely related-- successionally, floristically, edaphically, climatically, etc.-- oak-hickory forest-tallgrass prairie savanna) were treated under Miscellaneous Grasslands.

Braun (1950, ps. 177-191), the ultimate authority of the eastern deciduous forest, interpreted the Forest-Prairie Transition as part of the Oak-Hickory Forest Region. She distinguished the Prairie Peninsula Section (Braun, 1950, ps. 185-191) as distinct from the Mississippi Valley Section and Cross Timbers. Shelford (1963, ps. 306-319) treated the Prairie Peninsula, without using this designation or citing Transeau (1935), within a larger ecological unit or biotic commuity he called "grassland-deciduous forest contact". Miscellaneous references to or brief descriptions of the Prairie Peninsula included (McPherson, 1997, ps. 34-37). Nelson (1987, ps. 59-74) recognized nine savanna natural communities in Missouri (including those ecotones in both the glaciated plains and the Ozark Plateau (Ozark Mountains): 1) dry savanna, 2), dry-mesic savanna, 3) mesic savanna, 4) wet-mesic savanna, 5) limestone/dolomite savanna, 6) chert savanna, 7) sandstone savanna, 8) sand savanna, and 9) igneous savanna. Most, if not all, of these could be interpreted as part of the greater Prairie Peninsula (including isolated ecotones within oak-hickory forests such as those of the Ozarks). All of these were lumped and described together generally (and simplistically) as Savanna, SRM 801, rangeland cover type by the Society for Range Management (Shiflet, 1994).

65. Oak-hickory-tallgrass savanna- The Ozark Plateau of Missouri, Arkansas, Oklahoma and southeast Kansas is the prominent transition between the western-most extension of oak-hickory forest and the Cherokee Prairie dominated by big bluestem and Indiangrass with such associated species as little bluestem, switchgrass, tall dropseed and leguminous and composite forbs. This example of the Ozark Highland province is a community of both red and white oaks such as post oak, blackjack oak (Quercus marylandica), black oak (Q. velutina), northern red oak (Q. rubra= Q. borealis), and both black or Texas hickory (Carya texana) and white or mockernut hickory (C. tomentosa= C. alba). There was an obvious shrub layer of dogwood (Cornus florida) and redbud (Cercis canadensis). Big bluestem is so dominant as the understory herb that local hillbillies demonstrate their ecological folk wisdom and know it as “timber grass”. Conspicuous forbs included Baldwin ironweed (Vernonia baldwinii), rosinweed (Silphium integrifolium); tickclovers (Desmodium spp.), along with trailing lespedeza (Lespedeza procumbens), roundhead lespedeza (L. capitatus), slender lespedeza (L. virginica), and serecia lespedeza (L. cunneata), this latter a naturalized agronomic (and, now, weedy) species.

Stoney Point Savanna in Ottawa County, Oklahoma. September; late estival to early autumnal aspect Ecotone between FRES No. 15 (Oak-Hickory Forest Ecosystem) and FRES No. 39 (Prairie Ecosystem). Clearly K-73 (Mosaic of Bluestem Prairie [K-66] and Oak-Hickory Forest [K-91]. SRM 801 (Savanna). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Woods et al., 2005).

66. Winter range on an oak-hickory-tallgrass savanna- Winter vegetation of a relict savannah in western Ozark (Springfield) Plateau as an ecotone between tallgrass range community of Cherokee Prairie to the west and oak-hickory forest range to the east. These three progressively closer views are of the same savanna range introduced immediately above with closer location to the two farthest trees in background of above photograph. Those two trees were old-growth, open-crown form of northern red oak.

Except for presence of trees and local shrubs this range vegetation was tallgrass prairie dominated by big bluestem with Indiangrass as associate and with little bluestem, purpletop, and beaked panicgrass as other major grass species. Broomsedge bluestem, a native invader, and tall fescue (Festuca arundinacea), an introduced and frequently naturalized invader, were absent from this pristine sward. Species of native forbs, which also attested to the climax state of this savanna vegetation included tickclovers; roundhead, trailing, and slender lespedeza (all three being species of native Lespedeza); and rosinweed. Baldwin ironweed, an invasive though native composite, and the introduced-and-turned-weedy serecia lespedeza were the local "unwanted guest". These were not major components of this nearly virgin vegetation. Shrubs present in these three "nested photoplots" included blackberry (Rubus sp.), a few smooth sumac (Rhus glabra), and, as presented below, fox or frost grape (Vitis vulpina) in trees. Other shrubs such as eastern redbud and flowering dogwood that were present lower down on this hill (shown in above slide) were absent from the range plant community shown here. There was sexual reproduction of northern red oak with several seedlings growing less than height of the apparently parent trees shown here.

Various Quercus and Carya species that were present in photographs taken at greater spatial scale were not present in these scenes so they were not listed. These other tree species were listed under captions describing photographs that included representatives of those trees.

Stoney Point Savanna in Ottawa County, Oklahoma. September; late estival to early autumnal aspect Ecotone between FRES No. 15 (Oak-Hickory Forest Ecosystem) and FRES No. 39 (Prairie Ecosystem). Clearly K-73 (Mosaic of Bluestem Prairie [K-66] and Oak-Hickory Forest [K-91]. SRM 801 (Savanna). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Woods et al., 2005).

67. Northern red oak and friends on an Ozark savanna- A senescing northern red oak (one of the two shown in the preceding slides) with fox or frost grape as a sidekick grew on a rocky ridge of an Ozark Plateau savanna of prairie tallgrasses and trees of various oak and hickory species. These species were listed in some of the above captions and were not repeated here because northern red oak was the only tree species shown in photographs of winter vegetation. Other plant species present within radius of this tree's height included big bluestem, Indiangrass, little bluestem, purpletop, beaked panicgrass, slender lespedeza, trailing lespedeza, roundhead lespedeza, tickclover species, blackberry, rosinweed, and Baldwin ironweed among natives and serezia lespedeza, a naturalized agronomic forage.

Stoney Point Savanna in Ottawa County, Oklahoma. September; late estival to early autumnal aspect Ecotone between FRES No. 15 (Oak-Hickory Forest Ecosystem) and FRES No. 39 (Prairie Ecosystem). Clearly K-73 (Mosaic of Bluestem Prairie [K-66] and Oak-Hickory Forest [K-91]. SRM 801 (Savanna). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Woods et al., 2005).

68. Another red oak and some of the same friends on the same savanna- A second senescing northern red oak (and the second one introduced above) with a second fox or frost grape serving as an arboreal layer escort. Other range plants that grew within the distance equal to radius of this tree's height included Other plant species present within radius of this tree's height included big bluestem, Indiangrass, little bluestem, purpletop, and beaked panicgrass among the common native Gramineae. The Leguminosae was extremely well-represented by such natives as slender lespedeza, trailing lespedeza, roundhead lespedeza, and tickclovers as well as the naturalized introduced forage species, serecia lespedeza. Major native composites were rosinweed and Baldwin ironweed. Some species of dewberry (Rubus sp.) was twinning at the burled based of this old codger.

Cause of this burl was unknown, but the author strongly suspected that frequent fires in decades past was one factor. This tract of native pasture was frequently burnt 30 to 40 years prior to time of photographs (when the author attended the one-room school just across a county road and looked forward to spring fires).

Stoney Point Savanna in Ottawa County, Oklahoma. September; late estival to early autumnal aspect Ecotone between FRES No. 15 (Oak-Hickory Forest Ecosystem) and FRES No. 39 (Prairie Ecosystem). Clearly K-73 (Mosaic of Bluestem Prairie [K-66] and Oak-Hickory Forest [K-91]. SRM 801 (Savanna). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Woods et al., 2005).

69. Litter layer- Land surface layer beneath the first northern red oak (one without the burl) shown in detail above. Fallen across the carpet of bronze-colored leaves of this old, oaken, Ozark denizen were shoots of big bluestem, Indiangrass, and little bluestem. Students of range vegetation must bear in mind that the surface layer is part of the plant community, and destined to become part of the O horizon of the soil that supports it.

Stoney Point Savanna in Ottawa County, Oklahoma. September; late estival to early autumnal aspect Ecotone between FRES No. 15 (Oak-Hickory Forest Ecosystem) and FRES No. 39 (Prairie Ecosystem). Clearly K-73 (Mosaic of Bluestem Prairie [K-66] and Oak-Hickory Forest [K-91]. SRM 801 (Savanna). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Woods et al., 2005).

Personal perspective: What the author dubbed Stoney Point Savanna was just north (a hundred yards or so) of Stoney Point North No. 7 School, a rural district housed in a fine (and new) yellow brick building with one classroom inside, at which this photographer received the first eight years of his education.(Stoney Points was a mile and a half from this would-be author's house and walking when the road was rough and bike-riding when it was smooth constituted the "comute".) There was another savanna with similar vegetation (though in somewhat lower range condition) immediately behind the schoolhouse (close to the white, clapboard outhouses). Frequently, from autumn through winter to sometime in the spring students at Stoney Point fashioned "straw huts" out of the tall shoots pulled from the large clumps of prairie grasses growing among the oak and hickory trees on the ungrazed savanna (just beyond the schoolyard where students were supposed to play).

Students quickly learned that "timbergrass" (ie. big bluestem as this author discovered in later years) broke off easier and could be bent into shape and "stuffed in" better than the straw from what was known as broomsedge. After being reinforced with a higher education in Range Management and Animal Science years and miles from Stoney Point the school boy who was to assemble the work shown here understood that "timbergrass" was also more easily "stuffed in" and processed out of reticulorumens and that, in fact, grazing animals chose "timbergrass" while avoiding broomsedge-- just Stoney Point school boys.

Many a scheme was concocted, many a boyhood dream dreamt, many a plot plotted, and many the incidents cogitated on within those "straw huts" of "timbergrass". Decades later and "schools where college students go" afterward, the lessons learned in the brick schoolhouse and on an "extramural" playground with prairie grass playhouses atop a rocky hill have remained. In retrospection from the backside of a career in higher education, this Stoney Point school boy can only conclude that the demise of the one-room school and its replacement with factory schools, bus routes, "organized sports", and computers was a profound and an irreplacable loss, an expensive though cheapened and lessened education. Not exactly this educator's concept of progress. Maybe someday somehow some of the benefits of that small, rural education will be rediscovered like the savanna across the road from Stoney Point school. Afterall, the "timbergrass" still grows tall on the rocky Ozark soil.

There is not an herbaceous layer in the understory, but a thick, mulch-like mat of oak and hickory leaves beneath layers of all-age oak and hickory. Likewise, flowering dogwood and redbud are so rare that the typical shrub layer is all but non-existant.

 This is not an ecologically "healthy" plant community. It is not forest, and if it was it would be a dysfunctional one. This is a native savanna that lost its natural understory of tallgrass species (big bluestem or "timber grass" is the dominant decreaser) due to  overgrazing by cattle, horses, and hogs coincident with relatively recent exclusion of fire which simultaneously killed out most of the prairie grasses while allowing an unnatural increase in tree density which resulted in complete canopy cover in turn preventing regeneration and development of the characteristic shrub and herb layers. Compare this vegetation to that of Stoney Point Savanna above. They are both Ozark Highlands Chert Savanna range site.  

If the pre-white man Ozark Plateau vegetation was maintained as subclimax by Indians who set fires more frequently than the natural fire regime then designations of "fire type"or "fire disclimax" or, more generally, "anthropogenic climax or disclimax"would be appropriate. One could then argue that Indians were wildlifers instead of foresters and that they should have eaten squirrels instead of venison (or gone vegetarian), worshipped Smokey Bear, and dressed in Forest Service green.

The Ozark Mountains get plenty of "dry lightening" and best estimates are that an open oak-hickory-bluestem woodland similar to parklike conifer forest is the potential natural vegetation for some sites in the Ozark forest complex. The woody invasion in this photograph is not climax, the potential native vegetation; it is an example of range deterioration and improper vegetation management.

Proper management of forests, savannas, and bald knobs in the Ozark Highlands must include fire, and fire of intensity and frequency sufficient to reduce tree density and allow understory development. Buffalo Hills Natural Area, McDonald County, Missouri. Estival aspect. June. FRES No. 15 (Oak-Hickory Forest Ecosystem), K-72 (Oak Savanna, technically Oak-Hickory Savanna), Classified as chert savanna by Missouri Natural Areas Committee (Nelson,1987). SRM 801 (Savanna).Ozark Highlands- Ozark Plateau Ecoregion, 39a (Chapman et al., 2002).

71. Burnt-over oak-hickory-tallgrass savanna (limestone/dolomite savanna)- It was explained following the pop quiz with the preceding slide that much, probably most, of the vegetation of the Ozark Mountain Region experienced afforestation, formation of forests where forests had previously been absent under the existing climate. This phenomenon was probably best documented for the Ozarks in what is the present state of Missouri. Sources on which comparisons of present vegetation to pre-white man vegetation can be based range from personal accounts and journals of travelers to surveyor’s notes. The former were subjective and thus subject to misinterpretation by ecologists reading them two centuries later, but some were precise and written by the leading men of science of the day or at least by astute observers. The much-read journal of Missouri-Arkansas traveler, Schoolcraft (1821) is the best-known example of these. The meticulous notes of land surveyors— an unsung group of frontiersmen —have been analyzed and clearly served as a sound basis that showed extent of oak-hickory forest invasion into the oak-hickory-tallgrass savannas and tallgrass prairies of Missouri, especially the Ozarks. This increase in woody plants converted these savanna biomes into deciduous forests, or “brush patches”. Anyone doubtintg such woody invasion and afforestation of much of the Show-Me State, in particular it’s ancient Ozarks, should read— with a mind more open than the vegetation of the Ozarks— the analyses of such students of vegetation as Steryermark (1940, 1959), Beilmann and Brenner (1951), Howell and Kucera (1956), Kimmel and Probasco (1980), Schroeder (1982), and Natural Resources Conservation Service (1996, p. 41). A good introduction to the pre-Columbian (pre-settlement) vegetation of Missouri was presented by Thom and Wilson  (1980). Schroeder (1982, p. 13) quoted the native Missouri Ozarker and dean of American soil taxonomists, Curtis Fletcher Marbut, as writing that the Ozarks were:

“… up to the middle of the 19^th century a region of open woods, large areas being almost treeless. Except in roughtest land… the timber growth was not dense enough to hinder in any way the growth of grass. The whole region in its vegetation was more closely allied to the
western prairies than to the timber-covered Appalachians”.                    

The role and wisdom of the Indians in wise and skillful use of fire to maintain open forests, savannas, and prairies was mentioned with the preceding slide. It should be underscored that the earliest Caucasians in the Ozarks and adjoining prairies and savannas learned their lessons well from the American Indians and habitually fired the native Ozark vegetation. Fire was successively less employed as a tool in the progression (not necessarily progress) of groups of white man occupying the native land with their ever-increasing technological advancement. The first whites to enter the so-called wilderness were frontiersmen who set about converting the wilderness into the frontier, the transition between wilderness and thoroughly settled land (ie. “civilization”). From the eastern deciduous forest of eastern Canada to east Texas the first wave of frontiersmen were basically “a cross” between hunter-gathers and nomadic herdsmen (ie. “white Indians”). This first group of frontiersmen were historically designated the “American backwoodsman”. The backswoodsmen were the first group or social class of Europeans to start the process of technological civilization (Lippencott, 1933, ps. 182-183; Moore, 1957, ps. 57-58, 69, 71-76, 80, 93, 95). They were as unique and distinctive as the occupationally related fur trappers, expecially the immortal “mountain men”. The definitive work on the backswoodsmen— which have today been almost lost as a footnote in the pages of American history— and their ecological impact on the North American deciduous forest is the flawless study of Jordan and Kaups (1989). It is absolutely required reading for any who, like your author, would proudly proclaim: “Thank God I’m a hillbilly!” Sadly the bonafide hillbilly has about passed into the oblivion of his predecessor (and superior), the backwoodsmen. For all of their adverse effects on the eastern deciduous forests (eg. running free-ranging, unmanaged, “hog-wild”, feral swine in the woods; ovcerlogging, overtrapping and overhunting wildlife) backswoodsmen at least knew one thing that “civilized citizens” forgot: you need to burn the woods.

At some point shortly after World War II far-sighted professionals educated in ecological principles  (first, rangemen and wildlifers and, finally, foresters,) relearned the lessons of the Indians and the backswoodsmen, and prototype experiments with prescribed burning began. The history of fire practice on American ranges and forests was told in detail by Pyne (1982, 1984). Eventually Smokey Bear died (Hip, hip, hurray!) and even the fire-suppressing Forest Service “saw the light” (but only after more heat than light was generated) and began to practice— admittedly on a limited scale— the science and art of prescribed fire.

One example of that policy shift toward “pro-active” prescribed burning was captured on Kodachrome  and included for readers’ viewing pleasure in the above slide. This vegetation was of a black oak-dominated upland oak-hickory Ozark forest that had developed following decades of “protection from fire”. This involved joint action of such diverse groups as the Missouri legislature which passed anti-burning measures as early as 1824 (Schroeder, 1982, p. 21 [citing several authors]), settlers (mostly farmers) fearful of property damage from wild fire, many activists in the early days of the Conservation Movements, including of course the U.S. Forest Service and allied conservation agencies (eg. Missouri Department of Conservation), and even youth organizations like the Boy Scouts of America and 4H Club. When “scientific truth” was better refined and the ecological role of fire became widespread knowledge (it did not exactly spread like wild fire) the same groups came to appreciate the benefical use of fire and responded appropriately, even if belatedly.

One such example of this conversion (not yet fire in the bellies of all former fire-purging sinners) was prescribed firing of this former oak-hickory- tallgrass savanna that turned closed-canopy forest under fire exclusion (a de facto type conversion) for the purpose of savanna restoration. Viewers can readily see that it has a way to go to get back to the vegetation described by Schoolcraft (1821) and  land surveyors but it was a start. Actually the flames seemed to have sparked resolve in the oak and hickory species ,which were clearly invigorated, such that browsing wildlife (mostly whitetail deer) and other seral-disturbance species (eg. bobwhite quail) were the immediate beneficiaries of this range improvement project.  

In the view of the fired savanna-turned-forest shown in this slide the most immediate vegetational change was reduced canopy of the oak-hickory crown layer and “explosions” in populations of sassafras (Sassafras albidum), smooth sumac (Rhus glabra), buckbrush, persimmon (Diospyros virginiana), blackberry (Rubus spp.), pokeweed (Phytolacca americana), giant ragweed (Ambrosia trifida), and other old-field species. There was some release of such climax decreasers as big bluestem, little bluestem, and Indiagrasss as well as increasers like purpletop and invaders like broomsedge bluestem.      

Vegetation of the understory layers varied over small spatial scale existing as a patchwork of “mini”- (micro-) communities within the overall or general savanna-forest community that was subjected to the same fire treatment. A distinctively different understory community was presented in the next two succeeding photographs of this same management area, the same savanna (or forest if one chooses).

Details of prescribed fire history on this management area including fire management plan, fire regimen, and firing technique were unknown to author (and, in fact, apparently rather “smokey” to the Forest Service tour guide). 

North aspect but mid-slope (compare to hilltop of north slope in next slide).

FRES No. 15 (Oak-Hickory Woodland Ecosystem), K-72 (Oak Savanna). SRM 801 (Savanna). SAF— this is the interesting part —65 (Sassafras-Persimmon) which had been converted from the former SAF 110  (Black Oak). Ozark Highlands- White River Hills Ecoregion, 39c (Chapman et al., 2002). Limestone/dolomite Savanna. Mark Twain National Forest, Ava Ranger District, Buttram Hollow Allotment, Ozark County, Missouri. July.

72. Oak-hickory-tallgrass savanna (limestone/dolomite savanna) treated by prescribed burning- This was a slightly different view of the same general plant community presented in the prior slide. It was the same management area—the same small portion of “woods” burnt with the same fires. (The same clearing on the far hilltop can be seen or, as was often the case, at least it could be seen in the original slide prior to treatment as a j-peg and presentation in the compact disk.). It was specified in the preceding slide that the vegetation of the understory layers varied in a mosaic pattern over a relatively small surface area. In the part of the understory vegetation shown here prescribed fire resulted in a different plant community at local scale. Instead of releasing mostly seral woody species—namely sassafras, persimmon, buckbrush, and sumac—as in the local or micro-community shown above, here the same set of fire treatments released climax tallgrass species as well. Big bluestem and Indiangrass were the dominant grasses and the composite, black-eyed susan (Rudbeckia hirta), was the dominant forb present following prescription firing of this Ozark savanna. The major increaser was purpletop (Tridens flavus). There was also great abundance of the same woody species listed under the preceding photograph (primarily sassafras, persimmon, and smooth sumac), but dominance shifted among species and growth or life form. Phanerophytes were released to point of dominance in the local understory vegetation seen immediately above whereas in the “patch” of understory shown here the hemicryptophytes and cryptophytes (= geophytes) dominated the post-prescribed burn vegetation.

Dominant tree species were presented in the succeeding slide which was the third vantage point shown of this savanna-turned-forest-being-turned back-to-savanna vegetation.

This photo-point was more of the crest of a north slope aspect than that of the mid-slope seen in the preceding slide. This could could explain some of the difference in vegetation.

FRES No. 15 (Oak-Hickory Woodland Ecosystem), K-72 (Oak Savanna). SRM 801 (Savanna). SAF designation probably of limited value (if not meaningless), but SAF 65 (Sassafras-Persimmon) converted from a cross between SAF 110 (Black Oak) X SAF 40 (Post Oak-Blackjack Oak). Limestone/dolomite savanna. Ozark Highlands- White River Hills Ecoregion, 39c (Chapman et al., 2002).

Mark Twain National Forest, Ava Ranger District, Buttram Hollow Allotment, Ozark County, Missouri. July.

73.   Post oak-black oak-tallgrass savanna (limestone/dolomite savanna) maintained by prescription burning- This was the third focal or vantage point of a Ozark Mountain oak-hickory-tallgrass savanna that had developed such a dense woody component to the understory that the herbaceous layer(s) had become (or were becoming) lost. The savanna community was being replaced by forest; savanna was being or had been converted into forest. This was due to fire exclusion: “fire protection” (ie. suppression of the natural fire regime, whatever that might have been, was most certainly protection of the forest against fire). The “rub” was that the climax or potential natural vegetation for this site was not forest but savanna. The same species of trees— mostly black, post, blackjack oaks with limited northern red and white oaks and some hickory species —were common to both forms of plant community. The difference was in community form (physiogonomy, architecture, structure, tree density, and crown cover) and development of an herbaceous layer in the understory.

Fire suppression caused a type conversion. In fact, this was technically a biome conversion: ahardwood-tallgrass savanna— the ecotone between tallgrass prairie and oak-hickory deciduous forest— was converted (or was being converted) into a forest of anthropogenic origin (ie. it now was or was becoming a man-made forest; human action caused afforestation).      

This change in vegetation constituted ecosystem deterioration. From the perspective of Range Management this was range depletion. The range ecosystem was changed drastically based on departure of the plant community (along with native animals, the ecosystem consumers) from potential natural vegetation.

The dominant tree in this particular parcel of vegetation was post oak, but black and blackjack oaks were also present as associates. The prominent grass in center foreground was Indiangrasss. Big bluestem (known among local hillsmen as “timber grass”) was also common, but Indiangrass is a long shoot grass species and at mid-point in the growing seaon it was much taller and appeared generally larger than big bluestem which is a short shoot grass. (Beginning students in Range Management should master the concept of long shoot vs. short shoot. These classic references were highly recommended: Branson [1953], Rechenthin [1956], Younger and McKell [1972], Sosebee [1977, ps. 258-272]). Canada and Virginia wildrye were present as associate grasss species. Purpletop was the predominant increaser grass. Woody species common in the understorey included smooth sumac, buckbrush, and blackberry among shrubs. Tree regeneration was relatively high with seedlings and saplings of all the oak species (especially post oak) widespread (ie. prescribed fire did not prevent tree recruitment).

FRES No. 15 (Oak-Hickory Woodland Ecosystem), K- 72 (Oak Savanna). SRM 801 (Savanna). SAF is theoretically meaningless because this is an oak-hiockory-tallgrass savanna not a forest (thus technically not a forest cover type), but SAF 40 came closest on basis of  dominant species. Limestone/dolomite Savanna. Ozark Highlands- White River Hills Ecoregion, 39c (Chapman et al., 2002). Mark Twain National Forest, Ava Ranger District, Buttram Hollow Allotment, Ozark County, Missouri. July.

74. Ozark oak-hickory-tallgrass savanna (limestone/dolomite savanna) under fire exclusion- This was the “control plot” portion of the oak-hickory-tallgrasss savanna shown in the last three photographs. Complete “fire protection” of this check plot allowed conversion of a savanna community to a forest community. This was Smokey Bear’s woods whereas the last three slides were of a rangeman’s woods. This unburned part of the management area shown here was just across a Forest Service earthern road from the savanna subjected to prescribed burning shown in the three preceding slides. Tree regeneration (predominately post oak with black and blackjack oaks as associate species) was very high with all age classes of seedlings and saplings represented up to the near old-growth stage (tree on far left margin that was developing horizonal limbs). Compare the thick mulch of oak leaves, which in combination with closed canopy prevented any development of an herbaceous understorey, with the mosaic pattern of bare ground and understory layers of tallgrass and shrub species visible in the preceding slide.     

FRES No. 15 (Oak-Hickory Woodland Ecosystem), K-72 (Oak Savanna). SRM 801 (Savanna) is potential natural vegetation but here fire exclusion led to conversion of an oak savanna to a post oak-dominated forest cover type so no longer SRM 801 but SAF 40 (Post Oak-Blackjack Oak). This was example of afforestation and retrogression (disturbation-induced retrograde movement down a sere) with deterioration of native vegetation due to underburning (ie. an anthropogenic plant community). Limestone/dolomite Savanna. Ozark Highlands- White River Hills Ecoregion, 39c (Chapman et al., 2002). Mark Twain National Forest, Ava Ranger District, Buttram Hollow Allotment, Ozark County, Missouri. July.

75. Sampler of the Prairie Peninsula- Much of the potential natural (climax) range vegetation in the western Ozark Highlands and eastern Cherokee Prairie (of the Central Lowlands physiographic province) is a patchwork of oak-hickory forest, tallgrass prairie, and various combinations of these two major or general forest and rangeland cover types that form open woodlands and savannahs all of which together comprise the southwestern extension of the Prairie Peninsula (Transeau, 1935, Fig. 1). Range vegetation presented in these two photographs was an example of the species composition, structure, and spatial arrangement of the Prairie Peninsula at local contact between two distinctive natural plant communities: 1) tallgrass prairie dominated by big bluestem (foreground of both slides) and 2) post oak-blackjack oak-Texas or Ozark hickory forest (background of both photographs).

This oak-hickory forest (second-growth forest having climax species composition and structure) was invading the tallgrass prairie in absence of fire and perhaps other disturbances such as extreme drought which had not affected this area in the last half century. Seedlings and small saplings of the three dominant and defining hardwood tree species were conspicuous in the immediate and narrow contact zone between forest and grassland. Other tree species in the forest included black oak, black cherry, American elm, and occasional eastern red cedar. Presence of the latter, the only conifer indigenous to this general area, was indicative of fire cessation and suppression. Shrubs in the oak-hickory forest included blackberry, smooth and winged sumac, eastern redbud and flowering dogwood with latter two being much less common in this forest tract. Other important herbaceous species--in both understorey of forest and tallgrass prairie included various grasses including silky and Canada or nodding wildryes (Elymus villosus, E. canadansis, respectively), purpletop (Tridens flavus), beaked panicgrass (Panicum anceps), broomsedge bluestem (Andropogon virginicus), and naturalized tall fescue (Festuca arundinacea); legumes (notably ticktrefoils [Desmodium spp]); and such composites as woodland or stiff-haired sunflower (Helianthus hirsutus), the dominant forb, pale purple coneflower (Echinacea pallida), needleleaf goldenrod (Solidago gymnospermoides), tall goldenrod (S. altissima), and the annual daisy fleabane (Erigeron strigosus).

Newton County, Missouri. June, vernal aspect. Prairie Peninsula. Potential natural (= climax) vegetation was an ecotone of oak-hickory forest and tallgrass prairie: FRES No.15 Oak-Hickory Woodland Ecosystem; K-73 (Mosaid of Bluestem Prairie (K-66) and Oak-Hickory Forest (K-91) (Garrison, 1977). Combination of SAF 40 (Post Oak-Blackjack Oak) in Eyre (1980) and SRM 803 (limestone or chert variant of Missouri Prairie) in Shiflet (1994). Patchwork of Oak-Hickory Series, 122.11, and Bluestem-Tall-Grass Series, 142.11 ((Brown et al., 1998. ps. 37 and 40, respectively). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Chapman et al., 2002).

76. Hardwood invasion in the Prairie Peninsula- Gradual invasion of a local big bluestem-dominated tallgrass prairie by post and blackjack oaks and Texas or Ozark hickory from an adjoining oak-hickory forest of which these were the three dominant species. The seedlings and small saplings of these oak and hickory species were invading the prairie incrementally from the contact of the two range plant communities rather than throughout the grassland.

This photographer grew up in this locality and can distinctly remember when 50 years prior to the time of these photographs "burning off" of the woods was a spring ritual. To this author's pleasant memories as a boy blackberry picker these fires did not kill off blackberries (and certainly not the fire-l;oving sumacs), but there was considerably less dense cover of oak and hickory at that time when annual spring fires and hay-baling on the larger parcels of bluestem-Indiangrass prairie were taken for granted as standard practices in Ozark agriculture.

Newton County, Missouri. June, vernal aspect. Prairie Peninsula. Potential natural (= climax) vegetation was an ecotone of oak-hickory forest and tallgrass prairie: FRES No.15 Oak-Hickory Woodland Ecosystem; K-73 (Mosaid of Bluestem Prairie (K-66) and Oak-Hickory Forest (K-91) (Garrison, 1977). Combination of SAF 40 (Post Oak-Blackjack Oak) in Eyre (1980) and SRM 803 (limestone or chert variant of Missouri Prairie) in Shiflet (1994). Patchwork of Oak-Hickory Series, 122.11, and Bluestem-Tall-Grass Series, 142.11 ((Brown et al., 1998. ps. 37 and 40, respectively). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Chapman et al., 2002).

77. Details of oak-hickory invasion of bluestem prairie- In the Prairie Peninsula of the western Ozark Plateau post oak, blackjack oak, Ozark hickory and lesser cover of black oak and black cherry were invading a big bluestem-dominated prairie (beaked panicum, purpletop, Indiangrass were lesser species). Invasion was progressing from the forest-grassland edge with relatively little hardwood invasion in more interior parts of the tallgrass prairie. Encroachment of oak-hickory forest into other prairies that were conterminous with existing forest was by no means limited to this pattern of invasion from the perimeter. Nearby prairies were being lost to expansion of oak-hickory forest in which invasion was nearly uniform throughout prairies or even with invasion appearing to be more dense and rapid in more interior parts of bluestem grasslands.

Exact cuses(s) of forest encroachment was (were) not known, but folk wisdom, common sense, and personal observations by this authro implicate recent absence of fire. Many prairies were being invaded by hardwood tree species and eastern red cedar (juniper) that had not been grazed by ungulates other than white-teiled deer for a number of years. Livestock most certainly do not graze oaks and hickories in preference to grasses and they do not graze juniper at all.

Newton County, Missouri. June, vernal aspect. Prairie Peninsula. Potential natural (= climax) vegetation was an ecotone of oak-hickory forest and tallgrass prairie: FRES No.15 Oak-Hickory Woodland Ecosystem; K-73 (Mosaid of Bluestem Prairie (K-66) and Oak-Hickory Forest (K-91) (Garrison, 1977). Combination of SAF 40 (Post Oak-Blackjack Oak) in Eyre (1980) and SRM 803 (limestone or chert variant of Missouri Prairie) in Shiflet (1994). Patchwork of Oak-Hickory Series, 122.11, and Bluestem-Tall-Grass Series, 142.11 ((Brown et al., 1998. ps. 37 and 40, respectively). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Chapman et al., 2002).

The short sequence of five slides presented immediately below showed results of an early spring wildfire of moderate intensity that burned over a big bluestem-dominated prairie glade and through an adjoining upland, chert forest dominated by black oak (bitternut hickory [Carya cordiformis] was the major associate species) in the Springfield Plateau section of the Ozark Highlands. Other tree species included post oak, chinquapin (chinkapin) oak (Quercus muhlenbergii), American elm (Ulmus americana), and black cherry (Prunus serotina). This surface wildfire burnt in late March or early April when all hardwood and warm-season grasses and forbs were in dormancy. Over course of approximately the last four decades (less than a half century) there had been nor fires, logging, or livestock on this tract of oak-hickory forest and tallgrass prairie that is part of the southern portion of the Prairie Peninsula. In absence of fires or other disturbances (other than occasional ice storms) the upland black oak forest had invaded the big bluestem-dominated chert glade advancing from the forest perimeter outward so that the tallgrass prairie on the glade was becoming an oak-hickory forest. (Plant species were given below for each photograph.)

Effects from the wildfire (cause unknown) on ectonal range vegetation (that at edge of forest and grassland) were presented in the following five-slide sequence.Photographs were taken in late May and early June (approximately eight to ten weeks following the spring wildfire). Effects on the range vegetation in the interior of the black oak-bitternut hickory forest were presented in the chapter, Oak-Hickory Forest-II, in the Forests and Woodlands section of Range Types of North America. Both the big bluestem-dominated tallgrass prairie on the chert glade and the black oak-bitternut hickory upland forest were interpreted as climax (potential natural) range plant communities on this land from the perspective of polyclimax or climax pattern theory with topography and soils being determinative (ie. topographic and/or edphic climaxes) . From the monoclimax theory the tallgrass (big bluestem-dominated) prairie glade was preclimax to the regional climax of black oak-dominated and defined forest.

A mesic sugar maple-bitternut hickory forest on the north slope of a limestone bluff (above a creek) was conterminous with the upland black oak-bitternut hickory forest. In monoclimax theory this sugar maple-dominated forest that included white ash (Fraxinus americana), American elm, and basswood (Tilia americana) with an understorey of pawpaw (Asimina triloba), American bladdernut (Staphylea trifolia), and Jack-in-the pulpit (Arisaema triphyllum) and green dragon (A. dracontium) was postclimax to the regional, zonal, or climatic climax of black oak forest. Conterminous to the glade was go-back land that had been big bluestem-Indiangrass-prairie dropseed (Sporobolus heterolepis) tallgrass prairie prior to cultivation. On this prairie-turned farmland-abandoned-and-now-old field there was a large buffalo wallow that was less than a quarter mile from the sugar maple forested bluffs and the tallgrass prairie glade. This amazing mosaic of natural range vegetation that developed on a ptachwork of soils had almost unquestionably been maintained by some mixture of recurrent fires ignited by dry lightening or Indians, drought, buffalo grazing, wind and ice storms, a recipe of disturbances that will remain known only to God.

The role of fire in maintenance of the Prairie Peninsula and the associated savannah or woodland portions of range vegetation in the Oaark Plateau was presented for viewers education, and for the enjoyment of real rangemen who love to burn and delignt in the aftermath.

78. Trees meet grass, but it ain't romance- Range vegetation at edge of a big bluestem-dominated chert glade and an upland, dry-mesic, chert forest dominated by black oak as it appeared approximatedly eight to ten weeks following a wildfire that generated sufficient heat and height of flames to topkill black oaks that were roughly 40 foot tall with eight to ten inch diameters (DBH). There were fewer and smaller trees of post and chinkapin (chinquapin) oaks, American elm, and black cherry. The herbaceous vegetation in foreground was dominated by big bluestem with three-flower melic (Melica nitens)the assoicate speceis. Other herbs included the tallgrass species of Indiangrass, broomsedge bluestem (Andropogon virginicus), purpletop, and prairie dropseed along with such forbs as woodland sunflower (Helianthus hirsutus), Indian physic or American ipecac (Gillenia stipulata), goldern alexander (Ziza aurea), passion flower (Passiflora incarnata), and carrion flower (Smilax herbacea). Shrubs on the glade included blackberry (Rubus spp.), smooth suma, skunkbush sumac, coral berry or buckbrush, and summer grape (Vitis aestivalis). Seedlings and small saplings (up to slightly less than a yard tall) of post, black ,and chinquapin oaks (in that order of relative cover and density) had invaded the tallgrass prairie glade.

Range vegetation alone the perimeter black oak-bitternut hickory forest (vs. interior which was climax oak-hickory forest with multiple vegetational layers) included some individuals of the same species as on the glade plus pokeweed (Phytolaca americana), pointed-leaf or cluster-leaf ticktrefoil or, also, tick trefoil, or tick clover (Desmodium glutinosum), bigbract or large-bracted tick trefoil (D. cuspidatum) white vervain (Verbena urticifolia), and small skullcap (Scutellaria parvula) along with flowering dogwood, eastern redbud, shadbush or eastern serviceberry (Amerlanchier arborea), chinquapin oak, and black cherry. Also present--and as a key indicator indicator plant species--was eastern red cedar (Juniperus virginiana) along the forest-grassland edge and also occurring just on the outer zone of the forest interior.

The fire had topkilled essentiall all individuals of hardwood species on the glade, including blackberry, sumac, grape, and buckbrush. Most of these had resprouted so that several, years of aboveground biomass was removed (killed), but in process of being replaced quickly. In other words, periodic fires would be necessary for maintenance of glade vegetation.

Ottawa County, Oklahoma. June, late vernal aspect. Prairie Peninsula. Potential natural (= climax) vegetation was an ecotone of oak-hickory forest and tallgrass prairie: FRES No.15 Oak-Hickory Woodland Ecosystem; K-73 (Mosaid of Bluestem Prairie (K-66) and Oak-Hickory Forest (K-91) (Garrison, 1977). Combination of SAF 110 (Black Oak) in Eyre (1980) and SRM 803 (limestone or chert variant of Missouri Prairie) in Shiflet (1994). Patchwork of Oak-Hickory Series, 122.11, and Bluestem-Tall-Grass Series, 142.11 ((Brown et al., 1998. ps. 37 and 40, respectively). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Woods et al., 2005).

79. Looking down the edge- A "pyric" fence-line contrast of black oak-bitternut hickory forest (left) and big bluestem-tallgrass prairie glade (right) about eight to ten weeks after an early spring (late March or early April) wildfire of moderate intensity burnt this range vegetation (for the first time in over 40 years). This was a natural ecotone between two climax range types in a mosaic of Ozark Plateau potential natural vegetation consisting of oak-hickory forests, tallgrass paririe grasslands and glades, and savannahs and woodlands due to intermixing of the first two range plant communities.

Plant species were listed in the immediately preceding caption. Most of the taller trees on the edge of the upland, dry-mesic, chert oak-hickory forest were black oak (there were fewer and smaller trees of post and chinquapin oaks, American elm, and black cherry). Herbaceous species in understorey of the forest edge included many of those on the chert glade including the dominant species, big bluestem, along with blackberry, smooth sumac, skunkbush sumac, and buckbrush. The major forb at grassland-forest edge was Indian physic or American ipecac. The associate forb was woodland sunflower. There was also some of the pioneering wild or blue lettuce (Lactuca canadensis).

Details of this forest-grassland (glade) edge were presented and described in the two slides that immediately followed this caption.

Ottawa County, Oklahoma. June, late vernal aspect. Prairie Peninsula. Potential natural (= climax) vegetation was an ecotone of oak-hickory forest and tallgrass prairie: FRES No.15 Oak-Hickory Woodland Ecosystem; K-73 (Mosaid of Bluestem Prairie (K-66) and Oak-Hickory Forest (K-91) (Garrison, 1977). Combination of SAF 110 (Black Oak) in Eyre (1980) and SRM 803 (limestone or chert variant of Missouri Prairie) in Shiflet (1994). Patchwork of Oak-Hickory Series, 122.11, and Bluestem-Tall-Grass Series, 142.11 ((Brown et al., 1998. ps. 37 and 40, respectively). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Woods et al., 2005).

80. Prospering after fire (or happy grass on a glade)- Edge of a chert glade that adjoined an upland, dry-mesic black oak-dominated forest supported a rapidly growing fire-released, herbaceous range vegetationl of big bluestem, the dominant species, along with three-flowered melic, broomsedge bluestem, purpletop, Indian physic or American ipecac, the disturbance-colonized wild lettuce, carrion flower and passion flower. Woody species that had been topkilled, but that nonetheless and nothing-daunted had resprouted, included buckbrush, blackberry, smooth sumac, skunkbush sumac, summer grape, and post oak.

This forest and glade had not burned for over 40 years and woody plants had become established on the tallgrass prairie of the chert glade. This was a textbook case of the on-going, ecological, life-or-death "tug-of-war" characteristic between woody and herbaceous range vegetation in the grassland, forest, woodland, and savanna patchwork of natural range plant communities of the Prairie Peninsula (Transeau, 1935).

Ottawa County, Oklahoma. June, late vernal aspect. Prairie Peninsula. Potential natural (= climax) vegetation was an ecotone of oak-hickory forest and tallgrass prairie: FRES No.15 Oak-Hickory Woodland Ecosystem; K-73 (Mosaid of Bluestem Prairie (K-66) and Oak-Hickory Forest (K-91) (Garrison, 1977). Combination of SAF 110 (Black Oak) in Eyre (1980) and SRM 803 (limestone or chert variant of Missouri Prairie) in Shiflet (1994). Patchwork of Oak-Hickory Series, 122.11, and Bluestem-Tall-Grass Series, 142.11 ((Brown et al., 1998. ps. 37 and 40, respectively). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Woods et al., 2005).

81. The invading forest drivern back by flames- The advancing front of a black oak-dominated upland, chert, dry-mesic forest that was invading a big bluestem-dominated tallgrass prairie range in the Springfield Plateau of the Ozark Highlands. With the heavy fuel provided by four to eight-foot shoots of big bluestem, three-flowered melic grass (along with some Indiangrass, broomsedge bluestem, and purpletop) plus finner fuels of woody plants like smooth and skunkbush sumacs, blackberry, and summer grape, the trunks of forty foot (eight to ten inch DBH) black oaks were topkilled. Hurray! Pyric brush control.

Herbaceous species shown in this "photo-plot" included Indian physic or American ipecac (to right of charred logs and blackened trunk of black oak), woodland sunflower, big bluestem, passion flower, along with annual colonizing species including wild lettuce, common ragweed, and giant ragweed.Resprouting woody species included smooth sumac, buckbrush, blackberry, and, of course and very conspicuously, black oak.

Ottawa County, Oklahoma. June, late vernal aspect. Prairie Peninsula. Potential natural (= climax) vegetation was an ecotone of oak-hickory forest and tallgrass prairie: FRES No.15 Oak-Hickory Woodland Ecosystem; K-73 (Mosaid of Bluestem Prairie (K-66) and Oak-Hickory Forest (K-91) (Garrison, 1977). Combination of SAF 110 (Black Oak) in Eyre (1980) and SRM 803 (limestone or chert variant of Missouri Prairie) in Shiflet (1994). Patchwork of Oak-Hickory Series, 122.11, and Bluestem-Tall-Grass Series, 142.11 ((Brown et al., 1998. ps. 37 and 40, respectively). Ozark Highlands- Ozark Plateau Ecoregion, 39a (Woods et al., 2005).

82.A forester's dread and a rangeman's delight- Three poles of black oak at edge of an upland, dry-mesic black oak-dominated forest and a big bluestem-dominated tallgrass prairie on a chert glade were topkilled by an early spring wildfire of moderate intensity and flame height. The largest oak (about nine inches DBH) and the second largest (trunk on the right) had not stump-sprouted like the smallest black oak (middle trunk) did. This was only eight to ten weeks post-burn and perhaps too soon for suckering (production of long shoots) from basal shoots. Even if the larger black oaks do eventually resprout from stump, shoot,or rootcrown there was many years' worth of accumulated, aboveground biomass destroyed. There were resprouts of blackberry, smooth and skunkbush sumac, and buckbrush. This land had not burned in over 40 years.

Herbaceous range species like big bluestem, three-flowered melic grass, and purpletop along with perennial forbs such as Indian physic or American ipecac, carrion flower, passion flower, and woodland sunflower plus annual colonizers (eg. common ragweed, wild lettuce, giant ragweed) had immediate benefit from reduced shade, competition for soil water, and other enhanced habitat variables. Rangemen rejoice for such gifts the same as for those of precipitation.

Ottawa County, Oklahoma. June, late vernal aspect.

Ground zero of the inferno was now the scene of textbook Clementsian invasion with establishment of the annual forb, toothed spurge (Euphorbia dentata) and annual goosegrass (Eleusine indica) from the soil seed bank and vegetative recovery of the perennials, Johnsongrass (Sorghum halapense) and common bermudagrass (Cynodon dactylon) from rhizomes. All four species are aliens (exotics). Annuals are of the therophyte and perennials of the hemicryptophyte or cryptophyte life forms (Raunkiaer, 1934). The potential natural range vegetation of this habitat is a black oak (Quercus velutina)-dominated forest with an understorey of big bluestem (Andropogon gerardii) as dominant and various other grasses like purpletop (Tridens flavus) and poverty oatgrass (Danthonia spicata) as associate species. The climax plant community for this environment was obvious from range vegetation present on the other side of this county road (next slide). The preborn plant community present on spot of motor cycle crash site was bermudagrass, Johnsongrass, and hairy crabgrass (Digitaria sanguinalis) that was maintained by infrequent mowing. In less than two months after incineration in late spring most of the pre-burn naturalized plant species had reestablished. It was as if nothing had happened.

Lesson here is that plant responses to disturbance depend on any number and extent of variables, but responses to defoliation are similar regardless of defoliating agent (fire, natural or man-caused; range animal; drought; hail, wind, mechanical mower; plow; or human foot traffic). Yes, the innocent bare
feet of children on the school playground can have the same general impact as the motor cycle fire, plowing, or overgrazing. This depends on the defoliation factors of intensity, season, frequency, selectivity, and extent or area. For example, it might have taken bermudagrass longer to reestablish after the firry crash if the area of burn had been larger so that new shoots from rhizomes and/or stolons had to grown greater distances.

The fact is that while standard categories of range plants based on responses to defoliation (eg. decreasers, increasers, invaders) will vary to some degree with things such as animal species (selectivity), the general response of plant species is much the same to any and all agents of defoliation. In the classic work by Weaver (1954) and Weaver and Albertson (1956) species that decreased first and fastest under overgrazing also decreased first and came back last in response to the Great Drought (eg. big bluestem). Likewise, those species that persisted longest under overgrazing survived longest in prolonged drought (eg. cactus like Opuntia sp.). A reckless motor-cyclist provided an example of that ecological fact of range life.
A'rum, a'rum!

85. Oak-hickory forest and savanna— This is the widespread transition zone or intermediate community type between actual oak-hickory tallgrass prairie understory savanna and the western edge of the oak-hickory forest proper.Post oak and black hickory dominate the tree layer while black and red oak are associated species. Understory is primarily nodding or Canada wildrye and purpletop (Tridens flavus). Virginia creeper covers much of the understory and climbs into tree tops. Blackberry, buckbrush, Mayapple, and black-eyed susan dominate various microsites depending on cover of tree canopy. Chert savanna-chert forest composite type with fire determining which form prevails. June, late vernal aspect.

86. Winter twigs of black, Ozark, or Texas hickory (Carya texana)- Two examples of twigs of one of the smaller, commoner, and more wides pecies of hickory in the Ozark Plateau. Black hickory is a major and, often, a dominant tree in the western portion of the oak-hickory forest as well as the oak-hickory-tallgrass savanna.

Most of the various Carya species are extremely difficult to distinguish based on leaf, bark, and even fruit characteristics. One of the more useful groups of features for identification of the different hickories is characteristics of winter twigs, especially the terminal bud. These photographs presented winter twigs of Ozark or black hickory overall. The next two photographs showed more details with emphasis on terminal buds.

Ottawa County, Oklahoma. December; winter dormancy.

87. More specifics of winter twigs of Ozark hickory- Following presentation of the general winter twig of Carya texana in the preceding set of slides these two photographs displayed greater detail, particularily of the terminal bud, using two more examples from the same stand on an Ozark Plateau savanna.

Ottawa County, Oklahoma. December; winter dormancy.

88. Oak-hickory-tallgrass savanna (chert savanna) reclamation by prescribed fire- The Ozark Mountains (the Springfield Plateau portion of the Ozark Uplands or Ozark Plateau) vegetation shown here is the first stage of restoration of a pre-white man oak-hickory-tallgrass savanna that in absence of natural fire regimes developed into a post-climax anthropogenic (“man-made”) oak-hickory forest. The original pre-white man Ozark savanna vegetation such as that described by the various authors cited above (eg. Schoolcraft, 1821) was generally a savanna (or at best an open canopy woodland) with an open canopy of widely spaced oaks (post, white, blackjack, black, red, the latter common name being somewhat confusing but here referring to Quercus rubra var. rubra) and species of hickories including bitternut or pignut hickory (Carya cordiformis), shagbark hickory (C. ovata), black or Ozark pignut hickory (C. texana), and white or mockernut hickory (C. tomentosa). The strata of vegetation below the trees included seedlings and saplings of the trees, tall and mid-height prairie grasses, forest and grassland forbs, and understory shrubs of various sizes and growth forms.

This savanna— as are all savannahs by definition —was a transition zone between a biome dominated by woody vegetation such as forest and a grassland biome. Most of the vegetation of the western Ozarks was a savanna between the oak-hickory form of the eastern deciduous forest and the tallgrass prairies (eg. the large Cherokee Prairie) to the west.

As described in some detail earlier in this section on Ozarks savanna, white settlers or white sedentary farmers (not to be confused with the white frontiersmen known as backwoodsmen who were a combination of hunters- trappers, open range stockmen, and farmers “rolled in to one”) were fearful of wildfire and established effective (too effective for sound ecological management of native vegetation) fire exclusion from the Ozark savannahs. These transition communities— as is the case for almost all true savannas —were fire vegetation types and “protection” from fire resulted in deterioration of the vegetation (departure from climax) such that pre-Columbian oak-hickory-tallgrass savannahs  “thickened up” into oak-hickory forests with multi-layers of woody plants comprised of all age classes of the dominant oak and hickory trees as well as the native understory shrubs such as flowering dogwood, redbud, hazelnut (Corylus americana), and hop hornbeam (Ostrya virginiana) as well as woody vines and colony (patch)-forming woody plants like blackberry. Almost eliminated from this  “protected from fire” vegetation were the native herbaceous species (and their layers of vegetation) except for such vernal species as May apple (Podophhyllum peltatum). The native grasses were the species that were most excluded by the enhanced regeneration of trees as a result of fire exclusion. These included tallgrass species such as the dominant decreasers (big and little bluestem, Indiangrass, Canada and Virginia wildrye) and increasers (eg. purpletop), all of which were “headquartered” in and spread out from adjoining prairies. Climax grasses also included forest species like woodreed grass  (Cinna arundinacea) and beak grain (Diarrhena americana).

After 50 to 100 plus years of this unnatural fire exclusion, the savannas in many locations became almost “jungle-like” often approaching impenetrable thickets formed by: 1)the varying sizes of the oak and hickory seedlings and saplings, 2) the upper layer of shrubs like dogwood and redbud, 3) variouspatches of blackberry or buckbrush with all these “tied together” by 4) lianas (= woody climbers) like grape (Vitis spp.), Virginia creeper (Parthenocissus quinquefolia), poison ivy (Rhus radicans=Toxicodendron radicans), and trumpet vine (Campsis radicans). There was also a great increase in saplings and young trees of fire-susceptible tree species, especially black cherry (Prunus serotina).

This tangle became a home for the white man’s feral, mast-eating hogs (spelt “hawgs”). These acorn-eaters became famous (or infamous depending on proclivity of the individual hillbilly) as the Arkansas razorback, the equivalent of the Texas longhorn, but the forest range was of limited value to any other grazer or browser, including native whitetail deer and, especially, elk.

Utility and “beauty” of these “saved from fire”, Smokey Bear-forests also depended on the value systems and perspectives of different mountaineers and visitors (ie. “foreigners”). In as strict ecological sense, however,  these vegetative tangles or “triple-canopy woods” were disclimaxes to use the Clementsian term. The forester might view these newly formed forests as natural forests amenable to silvicultural and forest management practices while the stockman bemoans loss of grazing capacity on former savanna ranges.Thus, whether the changes were for the better or for the worse depends on one’s personal preferences based on commodity produced, attitude toward “beauty” or aesthetics, favorite pastimes, and so on. This particular example from the Ozarks illustrated human x environment interaction such that it  might even “… make it probable that there is no such thing as a ‘natural landscape’” (Carter, 1968, ps. 397-398). However, the ecological concept of a disturbance climax is scientifically valid. The preservation, conservation, and management of potential natural vegetation in this case necessitates actions known collectively as restoration, the most likely tool of which is simply the reintroduction of the environmental factor, the one component of climate, that man took out: fire. Now human co-action to restore what human neglect degraded requires as the tool of scientific management prescribed fire at regimes simulating those that occurred before Smokey Bear barged into “them thar hills”. 

Such restoration was “caught on film” in this and the next slide. Prescribed fire was used on this   portion of  a savanna-turned-forest five years prior to time of this photograph. Many of the oak and hickory trees as well as the less fire-tolerant species like black cherry were killed outright or only top-killed and resprouted, but both 1) total tree (canopy) cover and 2) cover of dominant climax tree species were reduced. However, cover and density (= regeneration) of seral tree and shrub species increased exponentially. The greatest increase was in sassafras followed by persimmon, smooth sumac, and blackberry, all of which are seral species. The two climax understory shrubs on sites like this are flowering dogwood and redbud. Redbud was released by prescribed burning (a specimen in front center of slide). There was also an increase in such climax decreaeser species as peaked panicgrass (Panicum anceps) and numerous tick clovers (Desmodium spp.), but there was also an increase in some invader species like broomsedge bluestem. Climax tallgrass species like big bluestem and Indiangrass had not yet emerged to any extent (again, five years post prescribed burn).     

Dominant trees in this local stand were black oak (two trees at far left) and white oak (center tree).

FRES No. 15 (Oak-Hickory Woodland Ecosystem), K-72  (Oak Savannna). SRM 801 (Savanna). SAF 64 which is Sassafras-Persimmon, a seral forest cover type. SAF designation misleading for three reasons:

89.    Degraded Ozark oak-hickory-tallgrass savanna (chert savanna) treated by prescribed burning- A natural chert savanna in the “tension zone” (= transition) between the oak-hickory form of the eastern deciduous forest and the tallgrass prairie was subjected to fire suppression (= underburning) for approximately four to six decades with result that tree regeneration was excessive (ie. at rates far in excess of natural recruitment, hence a woody invasion of the understory) and the savanna was converted into an anthropogenic forest. Vegetation specialists with various agencies of the state of Missouri wished to restore the climax or natural (the pre-settlement) savanna vegetation of this western Ozark Uplands or Ozark Plateau (specifically the Springfield Plateau). Prescribed fire was chosen as the tool of vegetation modification (restoration) by attempting to return the natural (pre-fire suppression action) fire regime(s).

Vegetation seen here was five years after the first prescribed fire (and probably about a half century since humans last “set the woods afire”, which was legally arson at that time). 

The two immediate results from the first prescribed burn were: 1) killing of some mid-size trees (trees of middle age clsasses) and top-killing (and subsequent resprouting) of younger trees and saplings and 2) release of seral tree species, especially sassafras and persimmon, and seral shrubs like smooth sumac, blackberries, and buckbrush. The dominant trees were black oak and white oak. Both suffered fire damage ranging from slight to severe at a local or microsite scale. Beaked panicgrass and broomsedge bluestem (the grass in the immediate center and left foreground) were released and increased substantially following fire, but climax tallgrass species like Indiangrass and big bluestem had not responded at time of photograph (five years post prescribed burning). The two dead trees in center are a black oak and a white oak.

FRES No. 15 (Oak-Hickory Woodland Ecosystem), K-72 (Oak Savanna). SRM 801 (Savanna). Irrelevance of SAF cover type designation was discussed under immediately preceding slide. Ozark Highlands- Elk River Hills Ecoregion, 39c (Chapman et al., 2002). Chert Savanna. Savanna State Park, McDonald County, Missouri. July.