WESTERN YELLOW PINE IN OREGON. 



9 



were on the south side of these bushes, 11 per cent were sheltered by 

 logs or lodgepole pines, and only 6 per cent were in the open, although 

 these open spots occupied a considerable proportion of the area. 



In the Blue Moimtains the reproduction of yellow pine is very 

 abundant, both in the virgin forest and after cuttings. Perhaps it 

 is more prolific here than anywhere else. In this region where an 

 area has not been burned over by a surface fire for a number of years, 

 there is quite commonly a veritable thicket of little trees from a few 

 inches to several feet high. Actual counts have shown that there are 

 sometimes 14,000 seedlings on a single acre, the ages ranging from 

 13 to 21 years. 



The first season most of the growth of the seedling is below groimd ; 

 it forms a top only 2 or 3 inches high with a small tuft of short needles, 

 but it grows a taproot from 7 to 12 inches long in its effort to reach 

 subsoil moisture. The second year more of a top is formed, but 

 growth is slow for at least four years, and does not become rapid in 

 any event untU the seedling has abundant fight. 



Table 3 gives an idea of the rate of growth of the dominant seed- 

 lings in average yeUow-pine forests in the Blue Mountains, which is 

 closely similar to the average growth of seedlings in other forests of 

 central and eastern Oregon. In making this table only seedlings 

 which had free growing space and looked as though they would live 

 at least to the pole stage were included. The growth of even these 

 dominant seedfings is exceedingly slow during their first 20 or 80 

 years. 



Table 3. — Seedling height growth, Blue Mountains, Oreg. 



[Based on 1,182 measurements.] 



Age. 



Height. 



Age. 



Height. 



Age. 



Height. 



Years. 



Feet. 



Years. 



Feet. 



Years. 



Feet. 



1 



0.2 



5 



0.8 



9 



1.5 



2 



.3 



6 



1.0 



10 



1.7 



3 



.5 



7 



1.1 



15 



2.7 



4 



.6 



8 



1.3 



20 



4.0 



EFFECT OF FIRES. 



Western yellow pine is classed commonly as a fire-resistant species, 

 probably because in its open stands destructive crown fires are rare; 

 but it is by no means immune to damage by fire. Occasionally a fire 

 gets into the tops of the trees in a pure yeUow-pine forest on a slope 

 and sweeps over the whole liillside, perhaps a square mile in extent, 

 killing all the trees in its path. This spectacular foiTn of fire damage is 

 uncommon, however; by far the greatest amount of damage is done 

 by surface fires which work in an inconspicuous way. Light, slowly 

 54891°— Bull. 418—17 2 



