10 FOREST RESOURCES OF TEXAS. 



favorable for timber growth, but the low rainfall precludes the pos- 

 sibility of luxuriant forest. The woody vegetation consists of the 

 characteristic chaparral, which is of arborescent height in the better 

 watered parts, but becomes reduced to dwarfed shrubbery in the most 

 arid areas. 



(5) Next in series inland lies the vast Cretaceous Belt including the 

 Black and Grand prairies and the Edwards Plateau, an area of some 

 40,000 square miles. The Black and Grand prairies are typical grass 

 prairie country, possessing timber originally only on the bottoms and 

 breaks of streamways and escarpment bluffs. Really the presence of 

 these features, together with the intrusions of the two tongues of sand- 

 bed country known as the Cross Timbers, brings a very considerable 

 amount of timber within this typically prairie region. The rainfall 

 would be sufficient to support rather heavy forest, particularly on the 

 Black Prairies, but the very compact, waxy soil of these prairies and the 

 impenetrable chalk beds of the Grand Prairie give grasses the advantage 

 over woody vegetation in their struggle for the ground. The Edwards 

 Plateau is very different. This is an area roughened by erosion, expos- 

 ing the limestone strata to the reception of rainfall, which, though 

 diminished to less than 30 inches, is still enough, under the physio- 

 graphic conditions, to support a heav} 7 though dwarfed timber covering. 

 The Edwards Plateau embraces some 15,000 square miles from the 

 southern province of the Great Plains Region. Toward the northwest 

 the altitude increases to over 2,000 feet, and it merges at last into the 

 Staked Plains. The southern border is ver}^ deeply dissected by erosion 

 into a hilly, almost mountainous country, which is natural timberland. 



(6) The Central Denuded Region is an area perhaps half as large as 

 the Edwards Plateau, from which the Cretaceous strata have been 

 eroded, exposing an area of granite at the south and of carboniferous 

 sandstone at the north. Both are rough areas, with hills, bluffs, and 

 gravelly flats or ridges favorable to timber growth. This is of post 

 oak on gravelly ridges, of mountain cedar on hills, and of mesquite on 

 flats. 



(7) The Red Beds Prairies comprise an area approximating 10,000 

 square miles in north central Texas, abutting on the Staked Plains. 

 Over this area the influence of -altitude, distance westward and inland, 

 and soils not especially pervious to water, leads to the complete pre- 

 dominance of grass vegetation except on streamways. 



(8) The Staked Plains, with an area of 44,000 square miles, are, so 

 far as soil conditions go, ideal for timber growth. The dryness of 

 the region, however, does not permit timber growth of any kind 

 except in canyons and on the escarpment bluffs. Where water is 

 available, as about ranches, trees flourish to an unusual degree, and are 

 hampered only by the severe winds. 



