EEPRODtrCTIOI^ OF WESTERN YELLOW PINE. 117 



Gregory (S) quotes the following from notes on the Navajo and 

 Hopi Indian Reservations by G. A. Glutches, supervisor of forests, 

 U. S. Indian Service : 



The reproduction of yellow pine over tlie yellow-pine type is very poor 

 and scattered. For the most part the reproduction can be considered as nil. 

 This is due to sheep and goat grazing. There are no signs of reproduction on 

 the cutover areas about the Navajo and San Juan Agency Mills. 



During the years 1918 and 1919 Assistant District Forester H. H. 

 Chapman made both intensive and extensive examinations on the 

 National Forests_pf Arizona and New Mexico. His observations 

 are valuable because of their extensive character and because his 

 investigations are independent of those previously made. A large 

 part of Chapman's work consists of comparisons between the repro- 

 duction on areas open to sheep as well as to cattle and horses and 

 that on fenced areas from which sheep have been excluded. One 

 method of investigation which had been neglected in former work, 

 but which has been successfully employed by Chapman, is that of 

 searching out the more or less obscure grazing history of various 

 sections of the range. By this means he has established in a number 

 of instances that certain areas which supposedly have been heavily 

 grazed by sheep over long periods of years, have in reality not been 

 heavily grazed, or have been only periodically grazed by sheep. 

 Numerous unpublished reports and memoranda by Chapman show 

 that he regarded sheep gTazing as the primary cause for failure of 

 western yellow-pine reproduction on the Colorado Plateau. 



An extensive survey by Westveld and Kimball on the Coconino 

 and Tusayan Forests in 1919 to determine areas in need of protec- 

 tion from grazing in order to insure adequate reproduction, showed 

 that the average amount of serious damage on sheep range was 33 

 per cent for seedlings between 2 years of age and 6 inches in height 

 and 21 per cent for those between 6 inches and 3 feet. The number 

 of seedlings below 3 feet in height averaged two and a half times 

 as great on areas from which sheep were excluded as on those grazed 

 by sheep together with other stock. 



INVESTIGATIONS OF 1919-1921. 

 EXAMPLES OF DAMAGE BY SHEEP GEAZING. 



One of the simplest ways of securing concrete evidence of the 

 effect of sheep grazing upon reproduction is by comparing inclosed 

 areas grazed only by cattle and horses with surrounding areas 

 grazed also by sheep. Small pastures established by homesteaders 

 in different parts of the forest furnish numerous opportunities for 

 such comparisons. Almost invariably wherei an area has been 

 fenced against sheep 10 years or more it shows strikingly better 



