EFFECT OF GRAZING ON WESTERN YELLOW PINE. 25 



lings, which at 10 years of age will be approximately 30 cents per 

 acre or $0,001 per tree if there are less than 300 seedlings per acre, 

 and at 20 years 75 cents per acre or one-third of a cent per seedling 

 where there are less than 250 per acre. These values, which are based 

 on an average annual increment (for a 150-year rotation) of 100 board 

 feet per acre and a stumpage price of $5 per 1,000 feet, are liberal. 1 

 With an average annual increment of 200 board feet, which may be 

 possible on the best sites, the loss would be 60 cents and $1.50 per acre 

 at 10 and 20 years. 



In case of restocking open burns, clear-cut areas, or plantations, 

 where the reproduction must be replaced artificially, the loss will be 

 the above cost plus the cost of restoration, which has been estimated 

 at $9 per acre for eastern Oregon; $10 per acre, or 4 to 5 cents per tree, 

 will cover the whole loss. Such areas of total destruction need not 

 occur with regulated grazing, except possibly in the case of a few 

 driveways which for topographic or other reasons can not be so 

 located as to avoid injury; and unless the range is overstocked these 

 can in any case be kept very small. 



BENEFITS OF SHEEP GRAZING TO THE FOREST. 



Benefits to the forest resulting from the use of the range may often 

 offset the slight damage done by regulated grazing. These benefits 

 may consist in direct aid to forest reproduction or in lessening the 

 danger of serious fires. 



AID TO REPRODUCTION. 



The value of sheep grazing in helping tree reproduction to start is 

 frequently overestimated. It does result in more abundant ger- 

 mination under certain conditions, viz, in case of heavy grazing on 

 poor sites. A pair of plots on a very poor lodgepole pine site, similar 

 in all respects except in the intensity of grazing on them, showed this 

 result: 



Bed ground, 

 1912. 



Lightly 

 grazed, 1912. 



Area (square feet) 



Seedlings over 1 year old . 

 Germinated, 1913 



800 



None. 



75 



800 



None. 



17 



In this case the soil was so dry and lacking in organic matter as to 

 be very unfavorable to reproduction, but the sheep, bedding in the 

 same place for several successive nights, left a thick layer of mulch, 

 so that seedlings not only germinated in greater numbers, but grew 

 much more vigorously than those on the lightly grazed plot. As is 

 usually the case where an area is excessively overgrazed, all of the 



i See Bulletin 418. 



