37 C) JOURNAL OF FORESTRY 



protection against sheep grazing would be taking a gambler's chance 

 not compatible with good silviculture. 



In their annual grazing reports for 1917, three supervisors in Dis- 

 trict 3 reported no damage, eight reported injury, but not serious. On 

 the Coconino injury by cattle on 2,000 acres of range was reported as 

 8 per cent of the reproduction and on sheep range 35,000 acres was 

 reported as having 25 per cent of the reproduction injured. For the 

 Sitgreaves Forest the supervisor reported no serious dmage except on 

 stock driveways and that reproduction of varying ages is excellent 

 over virtually all of the yellow pine belt. 



The data given apply primarily to western yellow pine. Sampson 

 and Dayton found on the Shasta National Forest that sheep injury 

 from browsing was greatest to white fir, western yellow pine coming 

 second and sugar pine third and Douglas fir least, except incense cedar. 

 Cattle appeared to prefer Douglas fir, with sugar pine second. 



Sparhawk concluded that "a. much larger proportion of western 

 yellow pine seedlings less than a year old are killed (by sheep grazing) 

 than of Douglas fir, while only half as many of lodgepole pine are 

 killed," but after the third year of growth western yellow pine, as a 

 general thing, is less liable to be killed than Douglas fir or lodgepole 

 pine. White fir, according to Sparhawk's findings is "practically never 

 browsed." 



Mason, in his bulletin on utilization and management of lodgepole 

 pine, makes the following statement regarding the protection of lodge- 

 pole from grazing: 



"Ori recently cut over areas, sheep grazing should be carefully regulated, if 

 a,llowed at all, until reproduction is well established. Where an unusually 

 heavy sod is an obstacle to reproduction, heavy grazing by sheep may be a 

 means of exposing the mineral soil." 



A study to determine the effects of grazing upon reproduction of 

 aspen was conducted by Sampson over a period of years on the Manti 

 National Forest.^ It was found that the leafage of young twigs of 

 aspen is browsed in varying degree by both sheep and cattle. Sheep 

 may be responsible for severe damage to aspen reproduction both in 

 standing timber and on clear cuttings, regardless of the variety and 

 supply of other choice forage. The damage from cattle grazing is 

 usually slight, except where the range is overgrazed and around water, 

 salt licks, and shading and bedding grounds where the cattle congre- 

 gate. 



* Sampson, Arthur W., Effect of Grazing upon Aspen Reproduction. U. S. 

 Dept. Agr. Bull. 741, 1919. 



