UNITED STATES DEPARTMENT OF AGRICULTURE 



1 BULLETIN No. 738 



JfLft^V^ 



Contribution from the Forest Service 

 HENRY S. GRAVES, Forester 



Washington, D. C. 



PROFESSIONAL PAPER 



December 19, 1918 



EFFECT OF GRAZING UPON WESTERN YELLOW 

 PINE REPRODUCTION IN CENTRAL IDAHO. 



By W. N. Sparhawk, Forest Examiner. 



CONTENTS. 



Timber and live stock 



Studies made on three grazing allotments — 



The Deadwood allotment 



The Silver Creek allotment 



The South Fork allotment 



Method of study 



Injuries to reproduction caused by sheep 



grazing 



Nature of injuries 



Amount of damage 



Sizes injured 



Season of injury 



Relation between amount of damage and 



intensity of grazing 



Cumulative effect of grazing 



Relation between amount of damage and 

 amount and character of forage 



Page. 

 1 

 2 

 3 

 4 



Comparison of the damage caused by 

 sheep and other agencies 



Valuation of damage 



Benefits of sheep grazing to the forest. 



Aid to reproduction 



Protection against fire 



Management of grazing 



Time to graze 



Page. 



19 

 22 

 25 

 25 

 27 

 27 

 27 



Intensity of grazing 28 



Methods of handling 28 



Herding 28 



Driveways 29 



Salting 29 



Watering 30 



Bedding 30 



TIMBER AND LIVE STOCK. 



The western yellow pine forest is the most important source of 

 timber in the area drained by the Columbia River and its tributaries 

 east of the Cascades and north of the Snake River Valley. There 

 are estimated to be approximately 7 million acres of western yellow 

 pine (Pinus ponderosa) in the National Forests of this region, and 

 there is probably an equal area outside the Forests. A conservative 

 estimate of the National Forest stand is 50 billion board feet. At a 

 growth rate of 100 board feet per acre per year 1 the western yellow 

 pine land within the National Forests alone is capable of producing 

 a sustained yield of 700 million board feet of lumber every year. 

 A considerable portion of the timberland now in private ownership 



i See U. S. Department of Agriculture Bulletin 418, "Western Yellow Pine in Oregon,"by T. T. Monger. 

 75256°— 18— Bull. 738 1 



