LOSS IN SEEDLINGS. 



27 



The silvicultural system practiced on Cutting Plot 3 was a com- 

 bination of the selection and diameter limit methods. Since indica- 

 tions pointed to the fact that Douglas fir and blue spruce reproduced 

 more satisfactorily than western yellow pine in a stand of this kind, 

 the latter species was cut under selection method, while spruce and 

 fir were cut to a 12-inch diameter limit. In this way it was sought to 

 open up the stand enough to check the reproduction of the tolerant 

 species, and at the same time favor the intolerant one. Future seed 

 crops of pine were insured by leaving several medium-sized trees. 

 All the mature and overmature yellow pines were removed. Spruce 

 and fir usually produce sufficient seed when from 10 to 12 inches in 

 diameter. It is recognized that such small plots as are dealt with in 

 this study will be greatly influenced by the surrounding stand, and 

 that therefore the method of cutting can have but little influence 

 upon seed supply and protection from wind. The method of cutting 

 will, however, influence light conditions, an important factor in the 

 regeneration of a stand of this character. 



LOSS IN SEEDLINGS. 



Table 13, based upon the seedling counts on Reproduction Plots 

 1 and 2, shows the loss in seedlings during the first four years of 

 growth. It may be seen that the greatest loss occurs during the year 

 following germination, and that the rate of loss decreases from year 

 to year. From the trend of the figures it is evident that the per- 

 centage of loss which occurs after the sixth or seventh year is very 

 small as compared to that in the early stages of development. 



Table 13. — Loss in western yellow pine, Douglas fir, and blue spruce seedlings from 



1 to 5 years old. x 





Loss. 



Period. 



Western 

 yellow 

 pine. 



Douglas 

 fir. 



Blue 

 spruce. 



From first to second year 



Per cent. 

 96.0 



Per cent. 

 96.8 

 83.3 

 42.8 

 54.0 



Per cent. 

 96.0 



From second to third year 



75.0 



From third to fourth year 



42.8 

 28.5 



57.1 



From fourth to fifth year 



25.0 







1 This table is based upon seedlings 2, 3, and 4 years old, as well as those 1 year old at the time of the 

 first count. 



FACTORS WHICH AFFECT LOSS. 



Light is one of the most important factors in the germination and 

 growth of forest seedlings. While conclusive light studies have not 

 yet been carried on within this type, it is evident that yellow pine 

 seedlings require a greater light intensity than either Douglas fir or 

 blue spruce, and that in early life Douglas fir requires more light 



