38 AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS. 



persimmon, Mexican walnut, palo bianco, Texas ebony, Texas catsclaw, 

 leucaena, devil's claw, coral bean, huisache, mesquite, koeberlinia, and 

 long stalk willow. 



During recent years the spread of chaparral growth northward from 

 the Eio Grande country has been remarkable. Large areas now wooded 

 are known to have once consisted of arid plains. This enroachment 

 undoubtedly tends to lessen the capacity of the country as a cattle range, 

 although a dense grass cover appears to occupy most of the land, except 

 during periods of severe drouth. 



ROCKY MOUNTAIN TYPES. 



The area in Texas occupied by Eocky Mountain species includes those 

 isolated foothills and mountains of the Trans-Pecos region which range 

 from 6000 or 7000 feet to 9500 feet in elevation. At such altitudes 

 extreme aridity is offset by reduced annual temperature and increased 

 rainfall, thus giving sufficient moisture to maintain tree growth in 

 favorable situations. Three chief mountain groups ore recognized; 

 namely, the Chisos, Davis, and Guadalupe ranges. Within these moun- 

 tain masses there are two important types; the timber of the foothills 

 and slopes, and the timber of the summits and high canyons. 



Timber of the Foothills and Slopes. 



This type includes some species found in the Edwards Plateau but 

 in general they belong to regions of higher elevation and are common 

 to the southern Rocky Mountains. The pinon pine is most widely dis- 

 tributed and is of the most importance. It is found occurring sparsely 

 on the slopes of Jtne higher mountains, on some of the northern slopes 

 and in the canyons of the Edwards Plateau west of the Frio River, 

 and in the Pecos and Palo Duro canyons. The species probably reaches 

 its best development in the Chisos Mountains of the Big Bend country. 

 With the pinon pine are found several species of cedar ( juniper ) f 

 Emory oak, and other species of little value. 



Timber of the Summits and High Canyons. 



The tree growth in this type consists of isolated islands of Rocky 

 Mountain species, of which western yellow or bull pine, Douglas fir,, 

 and limber pine make the largest growth. Such timber is limited to 

 the Guadalupe, Davis, and Chisos Mountains. Associated with these 

 are Emory oak, cedar, and other species. The Emory oak is said to 

 become a tree of from two to four feet in diameter and sixty feet in 

 height, but the growth of all species is generally short and scrubby. 

 Little information is available as to the abundance and uses of the 

 various Rocky Mountain trees in the Trans-Pecos region. It is prob- 

 able that much of it has already been cut in connection with the mines 

 and ranches. As a protection to steep slopes and for fuel and posts, 

 timber in this arid region is of great importance and its extension 

 should be encouraged by every means possible. 



