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

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FIG. 39/CO2 AND TEMPERATURE RECORDS FOR THE PAST 160,000 YEARS, FROM ANTARCTIC ICE CORES AND RECENT ATMOSPHERIC MEASUREMENTS. REPRINTED FROM HANSEN ET AL. 1993, NATIONAL GEOGRAPHIC SOCIETY, ©1993. CLIMATE OF EAST TEXAS/INTRODUCTION 73 almost orange color—the next day there will be a coating of dust on cars and other objects. An example is the “mammoth dust storm of January 25–26, 1965, which limited visibilities to one or two miles in such disparate locations as El Paso, San Angelo, Dallas, San Antonio, and Houston” (Bomar 1995). While irritating to the residents of East Texas, the loss of topsoil and its ecological and agricultural implications are serious issues for the western part of the state. Pollen, plant macrofossils, packrat middens, and other types of evidence demonstrate that the climate of Texas has changed substantially over the past 15,000 years since the end of the last glacial period. At 15,000 years ago, the mean annual air temperature was 5° C (9° F) less than at present, and there was a more widespread forest mosaic over most of Texas, with boreal species such as Picea glauca (white spruce) in specialized microhabitats (Bryant 1977; Stahle & Cleaveland 1995). Certain present-day plant distributions, such as the rare western occur- rence of plants normally found predominantly in eastern Texas, may thus reflect these past climatic conditions (see page 209). While past long-term climate change is well-documented, attention has focused recently on the possibility of future climate change in Texas due to human-induced modifications of the atmosphere (e.g., increased CO2 concentrations) and the resulting increased greenhouse effect and global warming (see e.g., Norwine et al. 1995; North et al. 1995a). While considerable controversy exists over details, there is solid evidence that global atmospheric CO2 concentrations have increased by about 31% since pre-industrial times and that this trend can be attributed primarily to human activities (e.g., fossil fuel use, land-use changes, and agriculture) (Houghton et al. 1995, 2001). In addition, over the past 160,000 years there has been a strong correlation between global atmospheric CO2 concentrations and average global temperatures (Fig. 39) (Graham 1999). However, there is controversy over whether CO2 concentrations can be characterized as the cause of these previous temperature changes. Since at least 1995, scientific consensus has existed that there is “…a discernible human influence on climate” (Houghton et al. 1995). More recently, Houghton et al. (2001) have indicated that “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.” Further, Houghton et al. (2001) note that the increase in temperature during the twentieth century is probably the largest to have occurred during the past 1,000 years, and that taken together, a number of trends “illustrate a collective picture of a warming world.” However, while the data clearly show a global warming trend, there is still uncertainty about the actual cause—some authorities believe the observed warming is at least partly the result of natural climatic fluctuations rather than human activities (e.g., Grossman 2001; Lindzen 2001).
74 INTRODUCTION/CLIMATE OF EAST TEXAS FIG.40/CROSS SECTION OF STEM OF PINUS TAEDA (LOBLOLLY PINE) FROM GRAYSON CO. SHOWING TREE RINGS (PHOTO BY W.C. WEATHERBY). Plants can contribute to an understanding of climate change in several ways. First, dendrochronology, the study of tree rings (Fig. 40), can provide information on past climate and thus a reference point for present and future studies (Stahle & Cleaveland 1992). Extensive tree-ring chronologies based on remnant old growth Taxodium distichum (bald-cypress) stands have provided accurate climatic reconstructions for the past 1,000 years for a number of areas in the southeastern United States, including Big Cypress (Bienville Parish) in northwestern Louisiana immediately adjacent to East Texas (Stahle et al. 1988; Stahle & Cleaveland 1992, 1995). In North Carolina, living bald-cypress trees up to 1,700 years old have been used to build a climate record extending back to A.D. 372 (Stahle et al. 1988). These ancient bald-cypresses are the oldest living trees in eastern North America (Graham 1999). Unfortunately, almost all old growth bald-cypresses in Texas have been destroyed by lumbering. However, in one location, Peach Tree Bottom along the Neches River in Jasper County, there is a cut-over area of bald-cypress where old cull trees were left when logging occurred. The oldest datable tree from this stand began growing in 1499 (D. Stahle, pers. comm.) and is thus more than 500 years old. Even older trees are present but are so damaged by heart rot that they are not useful for dating (D. Stahle, pers. comm.). Cook et al. (1996), using both living trees and dead (subfossil) logs, obtained a bald-cypress tree-ring chronology from this area covering the period 1255–1993, making it the longest tree-ring record produced in Texas. Stahle and Cleaveland (1995) noted that tree-ring chronologies developed from bald-cypress trees and subfossil logs might eventually provide paleoclimatic data for the eastern half of Texas covering the past 2000 years. However, at present, the northwest Louisiana data provide the best available estimate of the climate of East Texas over the past millennium. On a shorter time scale, well-documented chronologies based on remnant populations of Quercus stellata (post oak) have yielded detailed information on the East Texas climate for
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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
Page 39 and 40: 22 INTRODUCTION/GUIDE TO GLOSSARY,
Page 41 and 42: 24 INTRODUCTION/GUIDE TO ABBREVIATI
Page 43 and 44: 26 INTRODUCTION/SUMMARY DATA ON FLO
Page 45 and 46: 28 INTRODUCTION/ACKNOWLEDGMENTS Kar
Page 47 and 48: 30 INTRODUCTION/AUTHORS’ NOTE Pre
Page 49 and 50: 32 INTRODUCTION/GENERAL GEOLOGY OF
Page 63 and 64: 46 INTRODUCTION/SOILS SOIL ORDER DE
Page 65 and 66: 48 INTRODUCTION/SOILS, EAST TEXAS B
Page 67 and 68: 50 INTRODUCTION/SOIL-RELATED GEOLOG
Page 77 and 78: 60 INTRODUCTION/SOILS OF BLACKLAND
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 125 and 126: 108 INTRODUCTION/POST OAK SAVANNAH
Page 127 and 128: 110 INTRODUCTION/GEOLOGY AND SOILS
Page 129 and 130: 112 INTRODUCTION/SOILS, FIRE, AND T
Page 131 and 132: 114 INTRODUCTION/SOILS, FIRE, AND T
Page 133 and 134: 116 INTRODUCTION/ PRESETTLEMENT, EA
Page 135 and 136: 118 INTRODUCTION/VEGETATION OF POST
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124 INTRODUCTION/CONDITIONS TODAY O
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126 INTRODUCTION/POST OAK SAVANNAH
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128 INTRODUCTION/RED RIVER AREA are
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130 INTRODUCTION/BLACKLAND PRAIRIE
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132 INTRODUCTION/GEOLOGY OF BLACKLA
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134 INTRODUCTION/PRESETTLEMENT AND
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144 INTRODUCTION/VEGETATION OF BLAC
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146 INTRODUCTION/FUTURE OF BLACKLAN
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148 INTRODUCTION/FUTURE OF BLACKLAN
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150 INTRODUCTION/CADDO LAKE LOCATIO
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152 INTRODUCTION/CADDO LAKE FIG.84/
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154 INTRODUCTION/PRESENT AND FUTURE
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156 INTRODUCTION/BIG THICKET THE BI
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158 INTRODUCTION/BIG THICKET GEOGRA
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160 INTRODUCTION/NATURAL HISTORY OF
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172 INTRODUCTION/SUMMARY DEFINITION
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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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