SURVEY OF TEXAS WOODLAM. 



HIGHEST TEMPERATURES. 



FROST DATA. 



SUMMARY OF CHARACTER AXD CAUSES OF DISTRIBUTION OF TREE GROWTH.* 



Texas presents a great diversity of flora. f Some areas are densely 

 forested; others are vast treeless plains; others are stretches with scat- 

 tered trees; while still others are covered with low shrubs. The forests 

 follow in a general way the structural features in definite belts of 

 country but are modified, not to say controlled, by climatic variations. 

 The principal natural influences which have really determined the char- 

 acter and extent of tree distribution are rainfall, nature of the soil and 

 rock, temperature, sunlight and wind?. The first two are by far the 

 most important. Tt is often stated that where the annual rainfall is 

 less than 12 inches arid conditions are produced; that 12 to 18 inches 

 render the land suitable for grazing only; more than 18 inches are favor- 

 able for agriculture, while more than 100 inches produce vegetation too 



*A bulletin entitled "Deforestation and "Reforestation as Affecting Climate, 

 Rain, and Production.*' by Move Wick*, of the San" Antonio Scientific Society, 

 has been published by the State Department of Agriculture. Austin. Texas. 



rSee Bulletin 22. published by the University of Texas, Austin. Texas, entitled 

 "The Trees of Texas.'' by Dr. I. M. Lewis. 



