16 TIMBEE OF THE EDWARDS PLATEAU OF TEXAS. 



DISTEIBUTIOX AXD CHARACTER OF THE FOREST STAND. 



It- is not to be inferred from what has been said about the timber 

 vegetation of this region that the Edwards Plateau is covered with 

 continuous forest, even in its rougher parts. On the contrary, the 

 timber is very much interrupted l:)}^ open, grassy uplands. The presT 

 ent trend, however, is toward a continuous timber covering, and this 

 fact has significance for the future water supph^. Recalling the three 

 simple topographic elements comprised in the structure of the region, 

 viz, remnants of the plateau summit (or buttes and divides), moun- 

 tains, and canyons, we have the basis for classifying the vegetation 

 which forms a covering. This we may now consider more in detail. 



TIMBER OF THE CANYOXS AND STREAMWAYS. 



The tongues of luxuriant forest growth which follow the stream- 

 ways into the central limestone region are largely extensions of the 

 forests of the Atlantic Plain. In deep, well-watered and sheltered 

 canyons this timber attains large dimensions, and is a thick-canopied, 

 shady forest, under whose protection many shade-loving- shrubs and 

 herbaceous plants from the moister Eastern States have established 

 themselves. Thus is constituted a floral communit}' altogether unlike 

 that characteristic of the country roundabout; so that, in a floral zone 

 quite new and strange, one coming from the Atlantic States meets in 

 these canyons so many old friends of his native woodlands that he might 

 easily fancy himself at home. In such places c^^press has attained a 

 diameter of 5 feet and over, and sometimes a corresponding height. 

 The American elm, the sycamore, the pecan, the overcup oak, the 

 basket oak, the cottonwood, sometimes the Texas red oak. and the 

 hackberry l)ecome here large trees. Of smaller growth are black 

 cherry, box elder, walnut, soapberry, and many others. Beneath 

 these flourish dogwood, spicewood, buckthorn, smoke bush {Rhus 

 cotinoides)^ hollies, and black haw. In the rich, leaf-covered humus 

 the Canadian columbine grows under the ledges, and long fronds of 

 fern overhang the streamlet's edge. This timber on wider bottom- 

 land, however, is not so luxuriant nor so like typical Atlantic forest 

 a.s in narrow sheltered canyons. 



THE HILL AXD BLUFF TIMBER. 



Mixed thiiber. — This constitutes by far the larger part of the tim- 

 berland of the region. It abounds on the area of greatest erosion or 

 dissection of the plateau. This is the type of forest occurring, for 

 example, on the breaks of the Colorado, along the escarpment front 

 from Austin westward, and on the Guadalupe, the Pedernales, and the 

 Frio. It extends northward also upon the breaks of the Grand Prairie 

 and the jagged hills of the granite country. The stand of timber 



