18 TIMBER OF THE EDWARDS PLATEAU OF TEXAS. 



black haw. plum, sumach, aud holly, and much thorn\' smilax, grape- 

 vine, and other climbers. 



In addition to these types of mixed forest, which are distinguished 

 from one another by ditferences in density and growth rather than in 

 make-up. there are three very different types, two of which are charac- 

 teristically pure, while in the third two species of oak dominate the 

 mixture. These are mountain oak thickets, cedar brakes, and post 

 oak timber. 



^fountain oak thickets. — The mountain oak, also called Spanish oak 

 {Quercus schneckii, a mountain form of Quercus te.cana).^ makes a tall. 

 symmetrical, and rather rapid growth. Its timber is valuable for fuel 

 and for some other purposes. On slopes of low gradient (formed 

 especially by harder limestone which splits into large blocks), on the 

 sides of gorges cut in this harder limestone, and on the flat tops of 

 buttes this mountain oak establishes itself in dense thickets, and soon 

 makes a most effective covering and protection (PI. II, fig. 2). 

 Beneath it debris collects rapidly. Its close stand, its uniform, sym- 

 metrical growth, and its fresh, green, finely cut foliage give it a beauty 

 possessed by no other forest type of the region — a beauty which is 

 enhanced when, with the comino- of November frost, the folia o-e 

 assumes the richer hues of red and orange, quite unlike the gradual 

 somber browning of most deciduous foliage in this climate. 



Mountain oak is most eagerly bought for fuel: the tree sprouts up 

 quickly from the stump and is easily renewed. It ought to be more 

 generally established in this region. 



Cedar hrakes. — The writer knows of no region in which any species 

 of cedar is so uniformly abundant and dominant as is the mountain 

 cedar in the limestone country of Texas. By any structural charac- 

 teristic it is difficult to distinguish this tree from the red cedar of the 

 Atlantic States, yet in its natural occurrence it does not suggest the 

 red cedar at all. AVbile the red cedar is associated largely with bottom- 

 lands, and even with swampy bottoms, the mountain cedar is one of 

 the most pronounced and hardy xerophytic trees of all the arid South- 

 west. It is, in fact, one of the most valuable assets of the region, as 

 well as the most characteristic feature of the hill timber. It is most 

 conspicuous on the white, arid hills of crumbly limestone, because it 

 is there the dominant and practically the onh' species (PI. I, fig. 1; 

 PI. Ill, fig. 2). But it also grows in mixture with other species, and 

 attains its largest growth in the mixed forest of lower flats already- 

 described, where there is more water and richer, deeper soil. In such 

 situations the best yield of poles and ties is found. Reasonably clear 

 poles 20 to 30 feet in length and with a base diameter of from 1^ to 2 

 feet were formerly common. 



The typical cedar brake is an almost impenetrable growth, the inter- 

 locking branches of the close-set trees persisting to the very ground 



