Table 1 — Percentage of trees to incur substantial damage^ or mortality at Indian Springs site, for 

 three forage utilization levels: low, 20 percent;^ mid, 47 percent; high, 71 percent 



im n n r\ 



udrndyc 

 agent 







Forage utilization 



level 









Ponderosa pine 







Douglas-fir 





Low 



Mid 



High 



Low 



Mid 



High 



Nonanimal 



5.1 a^ 



4.9 a 



14.4 b 



0.6 a 



0.7 a 



4.9 b 



Gopher 



1.8 a 



1.7 a 



2.5 a 



2.1 a 



1.7 a 



4.7 a 



Rodent 



6.2 a 



.3 a 



.3 b 



5.0 a 



.3 b 



2.6 a 



Big game 



7.8 a 



1.7 b 



5.0 ab 



6.5 a 



.3 b 



1.4 b 



Livestock 



1.0 a 



.6 a 



2.2 a 



1.2 a 



.7 a 



.8 a 



Total 



21.9 a 



9.2 b 



24.4 a 



15.4 a 



3.7 b 



14.4 a 



■'Damage was determined from the overall vigor of the tree seedlings. Substantial damage percentages 

 included tree seedlings in vigor classes 3 or 4, as described in the appendix. 

 ^Actual utilization of range forage from field measurements. 



^Different le tters ind icate significant differences among utilization levels. The analysis was conducted using 

 the arc sine ly'percent transformation. 



Table 2 — Percentage of trees to incur substantial damage' or mortality at Tee Meadows site, for 

 three forage utilization levels: low, 36 percent;^ mid, 58 percent; high, 81 percent 



Forage utilization level 



Ponderosa pine Western white pine 



Damage . 



agent Low Mid High Low Mid High 



Nonanimal 



7.4 



2.7 b 



2.7 b 



2.9 a 



1.3 b 



1.0 b 



Gopher 



51.2 a 



66.3 b 



28.8 c 



61.2 a 



63.8 a 



26.6 b 



Big game 



2.7 a 



1.4 a 



.3 a 



1.7 a 



.0 a 



.0 a 



Livestock 



3.5 a 



2.4 a 



2.0 a 



1.6 a 



5.0 b 



5.8 b 



Total 



64.8 a 



72.8 b 



33.8 c 



67.4 a 



70.1 a 



33.4 b 



■I Damage was determined from the overall vigor of the tree seedlings. Substantial damage percentages 

 included tree seedlings in vigor classes 3 or 4, as described in the appendix. 

 ^Actual utilization of range forage from field measurements. 



^Different letters indicate significant differences among utilization levels. The analysis was conducted using 

 the arc sine ^ percent transformation. 



Livestock damage was significantly greater at the higher 

 utiUzation levels, with 5.8 percent damage occurring at the 

 high-utilization level and 5.0 percent damage occurring on 

 the intermediate-utilization level, as compared to 1.6 per- 

 cent damage at the Hght-utilization level. 



Overall damage was greatest to western white pine on 

 study sites receiving light and intermediate grazing inten- 

 sities. Like ponderosa pine, most of the damage was 

 caused by pocket gophers. The least amount of damage 

 occurred on the study site that received high utilization. 



Hume Creek 



Grazing intensity appeared to have little influence on 

 direct damage to ponderosa pine at Hume Creek (table 3). 

 The greatest differences in damage observed were a result 

 of wildlife- and nonanimal-related factors, with 12.5 per- 

 cent damage for nonanimal at the low-utilization level as 

 compared to 2 percent damage at high utilization. Wildlife 

 caused 6.1 percent damage at high utilization, with 

 1.2 percent damaged at the moderate-utilization level. 



Significant differences were found in damages caused by 

 livestock, with no damage at the low-utilization level and 

 2.7 percent damage at the high-utilization level. Also no 

 significant differences were detected in the total number 

 of ponderosa pine damaged at Hume Creek, with 11.3 per- 

 cent to 15.1 percent damage observed among the grazing 

 intensities. 



Significant differences in damage to western white pine 

 were observed among the three grazing intensities. Pocket 

 gophers caused the greatest damage (7.9 percent) in the 

 moderate-utihzation level, with 0.3 percent damage ob- 

 served in the low-utilization level. Wildlife caused 6.1 per- 

 cent damage in the high-utilization level and 1.4 percent 

 damage in the low-utilization level. Livestock damaged 3.8 

 percent of the western white pine seedlings and 0.3 per- 

 cent of the trees in the low level of utilization. Overall the 

 most damage to western white pine occurred under high 

 and intermediate levels of utilization, with 19.2 percent 

 total damage at high grazing intensity as compared to 

 7.5 percent damage at low utilization. 



4 



