White Fir in Klamath Basin. 355 



any commercial importance, however. Damage from fungous 

 diseases has been covered by a special report on that subject and 

 will not be mentioned here. 



Because of the unprotected resinous stems of Yellow pine 

 seedlings, and the dry surface conditions of the sites on which 

 they habitually grow, the lightest surface fire will ordinarily kill 

 all young seedlings of this species. On the other hand, the 

 dense cover of the White fir clumps keeps the ground beneath 

 cool and moist at all times, so that a light fire will not run under 

 them but is stopped at the edge with perhaps only a slight dam- 

 age to the seedlings on the outer border. Scattered individuals 

 would probably be killed, but since in the mixed stands the 

 majority of the White fir occurs in clumps it follows that the 

 damage to such a stand, resulting from a surface fire, is very 

 largely borne by the Yellow pine, and that repeated surface fires 

 must cause a decrease in the proportion of Yellow pine in the 

 stand. 



Development. A comparative study of White fir and Yellow 

 pine seedlings emphasizes a number of points that may be of value 

 in handling sale areas. 



For germination their requirements are similar although Yellow 

 pine prefers a mineral soil. For its development, however. Yel- 

 low pine is dependent on a deeper water supply than is White fir. 

 In this connection a comparison of the root systems is of interest. 

 (See cut at end of article.) The fact that Yellow pine will 

 grow on a rather dry site and that a light shade is beneficial, 

 makes it very well adapted to south and west slopes with chaparral 

 cover. On north and east slopes where surface moisture is more 

 abundant and the chaparral cover more dense, White fir forms 

 the greater part of the reproduction. 



During the first few years the height growth of Yellow pine is 

 much faster than that of White fir. After its early period of 

 slow growth, the White fir seedling develops in height at about 

 the same rate as the Yellow pine. In mixed stands, which 

 might follow fire or cutting, Yellow pine on account of this more 

 rapid initial growth, should be able to maintain its lead. Where 

 there is sufficient White fir to develop a heavy side shade it will, 

 by cutting down the crown areas, so reduce the height growth of 

 the Yellow pine that it will sooner or later be suppressed and 

 eliminated from the stand- 



