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

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CLIMATE OF EAST TEXAS/INTRODUCTION 71 (Bomar 1995). Houston and nearby areas have unfortunately experienced more recent inundations, including those resulting from Tropical Storm Allison. This storm, which stalled over the Houston area for five days in June of 2001, produced as much as 37 inches (94 cm) of rain and caused devastating flooding. The results included 22 fatalities in Texas and approximately $5 billion in damages, making it the costliest tropical storm in U.S. history (National Weather Service 2003a, 2003b). It should be noted that flooding in urban areas such as Houston is exacerbated by human-caused changes in hydrology (e.g., paving over large areas, and thus dramatically increasing runoff), while natural vegetation in many flood-prone areas (e.g., parts of the Big Thicket) absorbs water, reduces flood damage, is well-adapted to recurrent flooding and inundation, and is seldom permanently affected. In addition, Houston may possibly influence its own rainfall patterns. The “urban heat island” effect has long been known (e.g., Howard 1833; Streutker 2003). Caused by heat generation associated with human activities and the greater absorption of heat by asphalt, concrete, and buildings than by natural landscapes, cities are often warmer than surrounding areas. On hot summer days, urban air can be 2–10°F (1.1–5.6°C) hotter than the nearby countryside (Environmental Protection Agency 2003). However, it has recently been suggested that major cities, with their large amounts of rising hot air and turbulence caused by tall buildings, may actually generate convective clouds, thunderstorms, and rainfall locally. This appears particularly likely when there is a nearby source of moist air (e.g., the Gulf of Mexico) (NASA 2000; Goddard Space Flight Center 2003; Kluger 2003; Shepherd & Burian 2003). There is also an issue with ground subsidence along the Texas Gulf Coast. The excessive pumping of groundwater, combined with the increased weight from city development, has lowered the elevation of major coastal cities like Houston, leading to a heightened potential for increasingly damaging floods (D. Finfrock, pers. comm.; Neighbors 2003). Houston’s repeated bouts with natural disasters thus seem to be at least partly the result of a number of either predictable or human-caused problems—a large population living in a low-lying, naturally flood-prone coastal area, continuing hydrologic modifications making flooding ever more likely, ground subsidence, and human-induced weather changes. In a different part of East Texas, the incredibly sticky “black waxy” soil of the Blackland Prairie is particularly problematic during wet weather. Personal accounts (e.g., Mosely in Yelderman 1993) described how under wet conditions the dirt roads were virtually impassable and families actually went hungry until the ground dried enough for people to get to town to obtain food. Drought, on the other hand, is a bigger problem in the western part of East Texas, with the lack of water probably always being a limiting factor for humans as well as plants and animals. The relatively impermeable clay soils, the lack of dependable shallow water-bearing layers, and the scarcity and transitory nature of surface streams made the early Blacklands a particularly inhospitable environment. This difficulty was noted in the early explorer accounts, such as the one by D.P. Smythe (1852) who described a trip across the Blacklands: The soil improves now at every step becoming more level, and uniformly of a dark rich color, but the water is very bad and scarce, drying up entirely during the heat of the summer.… During the forenoon of today we must have traveled some twenty miles without passing over a spot of thin soil; being chiefly the black stiff ‘hog wallow’ prairie, rolling just enough to drain itself, but entirely destitute of water during the summer.… Josiah Gregg, another early explorer who traveled in the area in 1841–1842, indicated that in addition to droughts, the lack of springs or dependable water was “one of the greatest defects of this country” (Fulton 1941). Even today, the concentration of rainfall in spring and fall, coupled with hot dry summers, makes the water problem acute on the Blackland Prairie (Yelderman 1993). Currently, access
72 INTRODUCTION/CLIMATE OF EAST TEXAS to deep aquifers, such as the Trinity, and surface storage in large reservoirs (e.g., Cedar Creek Reservoir, Lake Lavon, Lake Lewisville, Lake Ray Hubbard, Lake Tawakoni, Lake Texoma), provide water for this water-poor western part of East Texas (Hayward & Yelderman 1991). However, Simpson (1993) has emphasized that, “Texas has been a water-deficit state since the dawn of recorded history” and that, “The problem will only be exaggerated as population growth expands.” Today, many cities and water-supply corporations in Texas are actively seeking access to more water, and some cities, such as San Antonio, have a serious water supply problem (Simpson 1993). At present, even the relatively water-rich eastern parts of East Texas are involved in controversies over this critical resource. Examples are recent (2002) efforts by the City of Marshall (Harrison County) to divert large amounts of water from Caddo Lake (with potentially devastating ecological and economic consequences) and plans to dam the Sulphur River to supply the Dallas area’s ever-increasing water needs. Other examples include plans and proposals to dam various East Texas streams to create reservoirs, in many cases to send water to drier areas to the west. Unfortunately, the result of such impoundments is the destruction of increasingly rare bottomland forest habitat with its high biological diversity (U.S. Fish and Wildlife Service 1985). The recurrent water difficulties seen locally are a reminder of the overall scarcity of water in the southwestern United States. Major thunderstorms and accompanying tornadoes have long been a problem in the region. At least the western part of East Texas, like much of the central U.S., is in the infamous “tornado alley,” a region of high tornado frequency (Perkins 2002a; Edwards 2003). Like the temperature extremes seen in the region, the frequent tornadoes are at least partly caused by the atmospheric instability resulting from the effects of the “climatic trumpet.” The unimpeded movement and clash of warm moist (tropical maritime) Gulf air from the south and cold air from the far north contribute to the formation of thunderstorms (including especially powerful ones called supercells that are characterized by rotation) and tornadoes over the Great Plains and adjacent areas. While tornado formation is not fully understood (Edwards 2003), a number of other factors, including dry air masses moving into the area from the Rocky Mountains to the west and Mexico to the southwest, are thought to be involved. The dry air can produce a “cap” above the warm, moist Gulf air near the surface. As the day progresses, more and more energy is trapped below the cap. Occasionally, enough energy accumulates in one area to punch through the cap, and an explosive thunderstorm or supercell forms. The result of this unique set of conditions—warm moist air from the south, cold air from the north, and dry air moving in from the west and southwest—is that nowhere else in the world has as many tornadoes as the central United States. In fact, some authorities estimate that up to 90% of the world’s tornadoes occur in North America (Flannery 2001). The two most devastating Texas tornadoes were those in Goliad in the southeastern part of East Texas in 1902 (114 fatalities) and Waco on the western margin of East Texas in 1953 (again 114 fatalities) (Bomar 1995). More recent destructive tornadoes (e.g., Paris 1982 (Bomar 1983), Jarrell in Williamson County 1997) and hail storms (e.g., car-bumper-deep hail in Rusk County in May 1976 (Bomar 1995), grapefruit-size hail in Fort Worth just west of East Texas in May 1995) are present-day reminders of the ongoing power of extreme weather events. The lightning accompanying thunderstorms can also have important effects. Lightning-started fires were probably frequent in presettlement times (Komarek 1966) and were undoubtedly significant in maintaining various fire-dependent plant communities in East Texas, including the Blackland Prairie and Arenic Longleaf Pine Uplands. A more unusual type of atmospheric event, dust storms, also affects Texas, including the eastern part of the state. Removal of the prairie sod cover from west Texas soils for agricultural purposes, coupled with drought and high winds, results in large amounts of soil particles being lifted into the air and transported long distances. While the problem is much worse in western Texas, occasionally the sky in various parts of East Texas can have a strange,
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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
Page 37 and 38: 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
Page 137 and 138: 120 INTRODUCTION/VEGETATION OF POST
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122 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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