Current Literature. 449 



show a maximum of cubic volume production. The tracts are, 

 however, at different elevations. The Glenada tract contains a 

 very dense stand of trees while the Saddle Mountain tract seems 

 to be about normally stocked, though somewhat below the aver- 

 age stocking for that age. The figures shown are for the average 

 of ten sample acre plots in each case. 



TABLE No. 7. 

 Effect of Density on Yield. 



FOR ALL TREES. FOR TREES 12" OR 

 MORE IN D. B. H. 



Tract ^zwuffibcrt'".--'** ^ h-i 



4-1 t) W 



,^ 



Glenada 39 years 510 9-0 225.7 7503 75 I37 76.9 2800 9,726 



Saddle Mt. 38 years 281 10.7 175.4 6477 90 i4-7 106.0 3929 20,661 



From this table it is evident that a densely stocked stand has 

 a backward effect upon the growth of the individual tree, as 

 there is no other factor which might have had influence upon the 

 tree growth. 



The most noticeable eft'ect of the overstocking is that the 

 Saddle tract with nearly 50% less trees per acre than Glenada 

 nevertheless has a larger average D. B. H. and only 13.6% less 

 yield in cubic feet. Still more favorable to Saddle is the com- 

 parison of trees 12 inches D. B. H. and over, for Saddle has 90 

 trees, Glenada only 75 and the cubic volume of these stems in 

 Saddle is 29% greater than in Glenada; the board foot volume 

 42% higher. This is because on the Glenada tract only about 

 15% of the trees are 12 inches or over, D. B. H. while on the 

 Saddle tract 32% are of merchantable size. 



Accordingly, density is a prime factor in the development of 

 Douglas fir stands, especially where the largest quantities of saw 

 timber are desired at the earliest possible time. 



In agreement with the Austrian experiments by Bohdannecky 

 and Schiffel, and the Russian plantations of Douglas fir by Dr. 

 Schwappach, Mr. Hanzlik reaches the following conclusions in re- 



