5IO Forestry Quarterly. 



try. Its top is flat and the sides are very steep, in places nearly 

 vertical. It is capped by a thick layer of lava, which has pro- 

 tected from erosion the old sedimentary rock beneath. On the 

 level areas where the pumice cover is thin, the irregularities of 

 the old flows show through as thickly scattered dykes and piles 

 of broken lava. 



The general elevation of this territory runs between 4,500 to 

 5,000 feet. The precipitation varies from 10 to 15 inches, mostly 

 in the form of saow, and killing frosts occur every month of the 

 year. The soil on the flats is composed almost entirely of pumice, 

 varying in size from rather fine dust to small gravel. There is 

 no humus. In places, as on the lower slope.* "^f some of the buttes, 

 the soil shows a somewhat clayey consisti:ncy wnere exposed by 

 the roots of upturned trees. It is probably due to the accumu- 

 lation of the finer pumice particles which have worked their way 

 down the slopes. 



The drainage is all underground, toward Silver Lake on the 

 east and the DesChutes River on the west. ]\Iost of the pre- 

 cipitation sinks directly into the ground, there being practically 

 no surface run off. It is to this condition that the DesChutes 

 River owes its remarkable uniformity of flow in all seasons. 



With this general impression of the country in mind, the ques- 

 tion of the timber itself may now be taken up. 



Lodgepole Pine and Yellow Pine are the only species with 

 which we are concerned, although White Fir (Abies concoJor) 

 and ^Mountain Hemlock may be found occasionally as scattered 

 individuals on the higher elevations. The undergrowth consists 

 mainly of chemise brush with manzanita and snow brush (Ceano- 

 tlms velutimis) on burns and more open slopes. Pine grass oc- 

 curs commonly in Yellow Pine stands at the lower levels, and 

 toward the edge of the desert other species of bunch grass are 

 found in varying proportions. There is very little grass of any 

 description under the typical Lodgepole Pine cover but on recent 

 bums which have not yet restocked, there is often a good growth 

 of the desert bunch grass. 



In comparing their silvical characteristics it is noted that a deep, 

 peri stent tap root is typical of both the Yellow Pine and the 

 Lodgepole Pine and that a loose, sandy or gravelly soil is best 

 adapted to their growth. Aside from these points, however, the 

 trees differ widely. During their early life either is readily killed 



