CLASSIFICATION OF THE FOREST. 33 



This encroachment of live oak shows how inadequate is the cultiva- 

 tion of that part of the coast country, and reflects the unfortunate 

 industrial conditions which allow lands unsurpassed for depth and 

 richness of soil to become relatively unproductive. 



THK KIO <;KANDE PLAIN CHAPARRAL. 



To one who had known the Rio Grande country forty years ago it 

 would never have occurred that this arid region could ever lay claim 

 to being in any sense a wooded country. Yet at the present time the 

 wooded area is vastly more extensive than the open prairie. The Rio 

 Grande Plain is now as truly a forested belt as are the more easterly 

 portions of the Atlantic Coast Plain, but its aridity has so stunted the 

 growth of the species as to make shrubs of them. The result is the 

 peculiar and characteristic chaparral, or pygmy forest. 



The associated species are of totally different stock from those hith- 

 erto considered. In geographic affinity they are mostly Sonoran 

 warm-temperate or semitropical desert species. A few of them are 

 really tropical. Of those which grow to valuable size, there are Texas 

 ebony, huisache, Texas catsclaw, mesquite, retama, and green-bark 

 acacia. These, it will be noted, are all members of the bean famity. 

 Four of these, and double that number of shrub species, are of the 

 mimosa kinship, a noteworthy fact, inasmuch as species of this kin- 

 ship form a conspicuous part of the vegetation in nearly all the large 

 arid regions of the earth Argentina and Chile, Central South Africa, 

 Australia, the Mediterranean countries, Persia, and Arabia. This fact 

 helps to give a comparative estimate of the cultural possibilities of the 

 Rio Grande country. In the selection of species for planting one could 

 cover {i range of trees far wider than would be possible on the dry 

 plains northward, including even hardy tropical or semitropical species. 



Besides the chaparral which for the most part consists of shrubby 

 species, often not exceeding -i or 5 feet in height the streams of the 

 Rio Grande plain have a considerable amount of timber characteristic 

 of the prairie streams, already discussed as river-bottom timber of 

 the prairie region, which, with the westward extension of the post 

 oak and the live oak types, furnishes a very considerable amount of 

 usable construction material and fuel. On the whole, the chaparral 

 is a very serious evil from its tendency to lessen the capacity of the 

 countiy as a cattle range. 



The geographic relation of the Texas region to the Atlantic Coast 

 Plain, to the northern prairies, the Great Plains, the Rocky Mountains, 

 the Mexican plateau, and the Gulf tropical zone is such that its vegeta- 

 tion as a whole shows affinities with all these regions. One may not 

 inaptly speak of Texas as the battle ground for supremacy of plant races. 

 In considering the timber vegetation we have continually noted the 

 _>, ;_>, is No. 47 04 3 



