24 



BULLETIN 738, U. S. DEPARTMENT OF AGRICULTURE. 



old, should have about 40 trees per acre. This would mean a volume 

 of about 10,000 board feet. A small, even-aged stand on the Payette 

 Forest, approximately 150 years old, had 230 trees per acre, prac- 

 tically all western yellow pine, between 10 and 22 inches diameter, 

 besides 160 trees below 10 inches; and its volume (trees 10 inches 

 and over) was approximately 23,000 board feet per acre. This is 

 very exceptional for a stand in virgin forest, but may be possible with 

 managed forests. 



If 40 trees per acre are assumed to constitute a full stand, but 0.4 

 as many seedlings as are indicated in Table 16 will be needed; but if 

 200 trees per acre are assumed, the figures in the table should be 

 doubled. If a full stand of Douglas fir is taken as 167 trees, 1 the figures 

 should be increased by two-thirds for Douglas fir stands. Assuming 

 250 trees per acre 2 as normal for lodgepole phie at maturity (140 years) 

 the figures in Table 16 should be multiplied by 2.5 — that is, there 

 should be approximately 3,700 seedlings the first year. 



Table 17. — Amount of reproduction on all plots, spring of 1914, reduced to a per acre 



basis. 



(All sizes up to o\ feet high.) 





Number per acre. 



Per cent of total. 



Allotment. 



West- 

 ern 

 yellow 

 pine. 



Doug- 

 las fir. 



Lodge- 

 pole 

 pine. 



White 

 fir. 



Total. 



West- 

 ern Doug- 

 yellow las fir. 

 pine. 



Lodge- 

 pole 

 pine. 



White 

 fir. 





3,450 

 6,580 

 5.050 



2, S70 2, 750 

 3,940 



910 



9, 070 

 11,430 

 7,120 



38 32 

 58 34 

 71 29 



30 





| 8 



South Fork 



2,070 













i 



Table 17, which shows the number of seedlings per acre actually 

 present on the plots on all three allotments in the spring of 1914, 

 indicates plainly that there was sufficient reproduction present to 

 make a full stand in spite of grazing injuries. On areas as well 

 stocked with reproduction as those covered by the study the com- 

 paratively small amount of scattered injury which results when the 

 stock is carefully managed can hardly be said to represent a tangible 

 loss of value. Where the number of seedlings present is already 

 insufficient to make a full stand at maturity, or where injuries are 

 concentrated, as on trails, bed grounds, or very seriously overgrazed 

 areas, so as practically to eliminate all reproduction over a continuous 

 area of any considerable size, there is a loss. 



If seed trees are present in sufficient quantity to reseed the area, 

 the loss will equal the value of the growth already made by the seed- 



Bulletin 418. 

 » See United States Department of Agriculture Bulletin 154, "Life History of Lodgepole Pine in the 



Rocky Mountains," by D. T. Mason, p. 31. 



