ILLUSTRATED FLORA OF EAST TEXAS - Brit - Botanical Research ...

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PRESETTLEMENT, EARLY SETTLEMENT CONDITIONS OF POST OAK SAVANNAH/INTRODUCTION 117 FIG. 69/ FRONTISPIECE FROM OLMSTED’S (1857) A JOURNEY THROUGH TEXAS, PROBABLY DEPICTING AN AREA IN THE POST OAK SAVANNAH, SHOWING A FORESTED STREAM BOTTOM WITH DWARF PALMETTO AND SPANISH MOSS AND A ROLLING SAVANNAH UPLAND WITH SCATTERED TREES. and tree-ring chronologies, based on trees from about 200 to more than 300 years old, have been obtained from numerous localities throughout the region (Stahle et al. 1985; Stahle 2002; D. Stahle, pers. comm.). In summary, presettlement vegetation of the Post Oak Savannah was probably a complex mosaic of prairie, post oak-blackjack oak savannah/woodland/forest, xeric sandyland, isolated pine-oak forests (e.g., “Lost Pines” of Bastrop County), dry-mesic forests (particularly in the north), bogs and other wetlands, and river bottom forests. Further, it should be kept in mind that when Europeans first observed the area, even though the vegetation pattern encountered was interpreted as static, it was “in a state of flux” (Smeins 1984). The situation observed was “only one slice through a continuous, multi-temporal series of changes. Climate had been changing and continued to change, fire frequency and intensity varied from place to place, the diverse herbivore fauna of the Early Holocene was gone and in its place the grasslands were dominated by one major herbivore, the bison” (Smeins 1984). In addition, Native
118 INTRODUCTION/VEGETATION OF POST OAK SAVANNAH Americans were present and possibly had significant impacts on the vegetation through such mechanisms as increased fire frequency. Holloway et al. (1987), based on pollen analysis of Weakly Bog in Leon County, suggested that the Post Oak Savannah became established only between 1,500 and 2,000 years ago as increasing aridity resulted in a vegetational shift from oak woodland to savannah-like plant communities. While the pollen data may represent a significant one-time shift in the vegetation, there have been numerous changes in vegetation since the end of the last glaciation (Bousman 1998), and the continuing “state of flux” (Smeins 1984) mentioned above should not be forgotten. Because of all these complexities, the exact presettlement vegetation pattern is particularly difficult to estimate. Animal life on the Post Oak Savannah was in general a mixture of that found on the adjacent Blackland Prairies and Pineywoods. Since detailed discussions are given for the Blackland Prairie and Big Thicket portion of the Pineywoods, no further discussion of presettlement animal life is given here. As settlers moved into the area, much of the Post Oak Savannah was rapidly converted to cropland or pasture. In the words of David Diamond of the Texas Natural Heritage Program (in Bartlett 1995): The prairies are more fertile, yet initially were harder to plow because they were clay soils, and so they were not plowed as quickly as the Post Oak Savanna. A lot of the savannas were plowed. They grew cotton or other crops, and the soil wore out quickly because it wasn’t as fertile as the Blackland Prairies. Later on, when the prairies were plowed, the Post Oak Savanna went back into rangeland of some sort and today is no longer plowed. Today, much has been cleared and large areas are occupied by economically useful exotics. As pointed out by Simpson (1988), it is “used largely for ‘improved’ pasture, with vast acreages sodded to Bermuda Grass and seeded to Bahia Grass.” On the other hand, large expanses of once-cleared land are now in second, third, or fourth growth woody vegetation. Thus, as a result of human impacts, little of the Post Oak Savannah is as it was during presettlement times. VEGETATION OF THE POST OAK SAVANNAH As mentioned above, while probably dominated originally to a significant extent by savannahs/open woodlands/forests of post oak and blackjack oak with a tall grass understory, the Post Oak Savannah was a complex mosaic of plant communities. The communities listed below, modified in part from Wilson (1989), Bezanson (2000), and MacRoberts et al. (2002b), represent the primary plant communities and give some indication of the complexity of the vegetation of the Post Oak Savannah. It should be noted, however, that there were and still are small areas of different, and in some cases, quite distinctive communities. An excellent example of this can be seen at the Gus Engeling Wildlife Management Area in Anderson Co., where Singhurst et al. (2003b) recently documented a number of interesting “vegetation alliances,” some of which have similarities to communities of the Pineywoods. These include the Sand Post Oak-Bluejack Oak Alliance (Quercus margaretta-Q. incana), the White Oak- Southern Red Oak-Post Oak Alliance (Quercus alba-Q. falcata-Q. stellata), the Loblolly Pine- Southern Red Oak Alliance (Pinus taeda-Quercus falcata), the Overcup Oak Seasonally Flooded Forest Alliance (Q. lyrata), and the Planer Tree Seasonally Flooded Forest Alliance (Planera aquatica). POST OAK-BLACKJACK OAK UPLAND SAVANNAHS, WOODLANDS, AND FORESTS—The dominant natural vegetation for much of the upland Post Oak Savannah was an open deciduous savannah/woodland/forest composed of Quercus stellata (post oak), Q. marilandica (blackjack oak), and other drought-tolerant species (e.g., Carya texana, black hickory) (Bezanson 2000) and an understory of tall grasses such as Schizachyrium scoparium (little bluestem),
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ILLUSTRATED FLORA OF EAST TEXAS
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ALLDREDGE, LINDA & JACK BATTERBAE,
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We would like to recognize and expr
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ISSN 0833-1475 ISBN 1-889878-12-X S
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“DEEP EAST TEXAS IS AN OLD, QUIET
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Elray S. Nixon E lray Nixon was bor
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ILLUSTRATED FLORA OF EAST TEXAS TAB
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TABLE OFCONTENTS/ PAGE APPENDICES A
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Hymenocallis liriosme
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ILLUSTRATED FLORA OF EAST TEXAS OVE
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4 INTRODUCTION/GEOGRAPHIC AREA OF E
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10 INTRODUCTION/MAJOR RIVERS OF EAS
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12 INTRODUCTION/PLANTS TREATED The
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14 INTRODUCTION/GUIDE TO ARRANGEMEN
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16 INTRODUCTION/GUIDE TO SOURCES OF
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18 INTRODUCTION/GUIDE TO GEOGRAPHIC
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20 INTRODUCTION/GUIDE TO ENDANGERED
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22 INTRODUCTION/GUIDE TO GLOSSARY,
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24 INTRODUCTION/GUIDE TO ABBREVIATI
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26 INTRODUCTION/SUMMARY DATA ON FLO
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28 INTRODUCTION/ACKNOWLEDGMENTS Kar
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30 INTRODUCTION/AUTHORS’ NOTE Pre
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32 INTRODUCTION/GENERAL GEOLOGY OF
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46 INTRODUCTION/SOILS SOIL ORDER DE
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48 INTRODUCTION/SOILS, EAST TEXAS B
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50 INTRODUCTION/SOIL-RELATED GEOLOG
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60 INTRODUCTION/SOILS OF BLACKLAND
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Page 83 and 84: 66 INTRODUCTION/CLIMATE OF EAST TEX
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Page 95 and 96: 78 INTRODUCTION/GEOLOGY OF PINEYWOO
Page 97 and 98: 80 INTRODUCTION/PRESETTLEMENT, EARL
Page 105 and 106: 88 INTRODUCTION/PRESETTLEMENT VEGET
Page 107 and 108: 90 INTRODUCTION/CURRENT VEGETATION
Page 123 and 124: 106 INTRODUCTION/POST OAK SAVANNAH
Page 127 and 128: 110 INTRODUCTION/GEOLOGY AND SOILS
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Page 147 and 148: 130 INTRODUCTION/BLACKLAND PRAIRIE
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Page 171 and 172: 154 INTRODUCTION/PRESENT AND FUTURE
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168 INTRODUCTION/NATURAL HISTORY OF
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170 INTRODUCTION/NATURAL HISTORY OF
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172 INTRODUCTION/SUMMARY DEFINITION
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174 INTRODUCTION/PRESETTLEMENT AND
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184 INTRODUCTION/HISTORY OF BIG THI
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190 INTRODUCTION/CONSERVATION IN BI
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200 INTRODUCTION/ORIGIN AND DIVERSI
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228 INTRODUCTION/CONSERVATION IN EA
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234 INTRODUCTION/HISTORY OF BOTANY
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244 INTRODUCTION/BOTANY IN NORTH CE
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246 INTRODUCTION/BOTANY IN NORTH CE
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248 INTRODUCTION/BOTANY AT UNIVERSI
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250 INTRODUCTION/BOTANY AT TEXAS A&
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252 INTRODUCTION/BOTANY AT TEXAS A&
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254 INTRODUCTION/OTHER CONTRIBUTION
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256 INTRODUCTION/CURRENT BOTANICAL
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258 INTRODUCTION/BOTANICAL ART IN E
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