Table 3 — Percentage of trees to incur damage^ or mortality at Hume Creek site, for three forage 

 utilization levels: low, 22 percent;^ mid, 41 percent; high, 68 percent 



Forage utilization level 



Ponderosa pine Western white pine 



agent 



Low 



Mid 



High 



Low 



Mid 



High 



Nonanimal 



12.5 a^ 



5.4 b 



2.0 b 



5.5 a 



3.2 a 



2.5 a 



Gopher 



.6 a 



2.5 ab 



3.4 b 



.3 a 



7.9 b 



6.8 b 



Big game 



2.0 a 



1.2 a 



6.1 b 



1.4 ab 



3.3 a 



6.1 b 



Livestock 



.0 a 



2.2 b 



2.7 b 



.3 a 



.6 a 



3.8 b 



Total 



■ 15.1 a 



11.3 a 



14.2 a 



7.5 a 



15.0 b 



19.2 b 



1 Damage was determined from the overall vigor ot 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 percent transformation. 



DISCUSSION AND CONCLUSIONS 



All sites considered together, direct damage from live- 

 stock was minimal. This was most apparent on the Indian 

 Springs study site where rotational grazing management 

 is practiced. There, direct grazing damage to both 

 Douglas-fir and ponderosa pine was negligible. In addition, 

 when rotational grazing is practiced, damage to tree seed- 

 lings was not found to be significantly different among 

 utilization levels. In contrast, at Tee Meadows and Hume 

 Creek, where rotational grazing is not practiced on the 

 high-utilization sites, overall damage was greater. Higher 

 grazing intensities appear to increase the potential for 

 significant damage, and the accumulative effect of con- 

 tinuous and heavy grazing could be substantial in later 

 years i 



The amount of seedling damage from_ big-game animals 

 was similar to that from livestock where terrain did not 

 limit livestock movement. On the Hume Creek and Tee 

 Meadow sites, livestock and big-game damage patterns 

 were similar. On these sites, terrain did not limit either 

 hvestock or big-game movement. Meanwhile at Indian 

 Springs, the greatest damage from big-game animals 

 occurred on the light-utilization level, where elk and deer 

 used scalped planting sites as "stair steps" on terrain too 

 steep for livestock use. Terrain or steepness of slope could 

 possibly be used as a controlling factor in minimizing live- 

 stock damage. Cutting units could possibly be designed to 

 take advantage of slope conformation to control livestock 

 damage. 



Nonanimal damage also appeared to be related to 

 grazing intensity on the Indian Springs site, with the 

 greatest damage to tree seedlings occurring on the high- 

 utilization site. This could be the result of past grazing 

 history; however, it was observed that the soils on areas 

 of steep topography were more developed than on areas of 

 gentle-to-moderate terrain. This phenomenon, which 

 resulted in poorer planting conditions for tree seedlings, 

 may be a result of the mass wasting that has occurred on 

 areas of steep topography, which routed talus material 

 around large rock outcrops. While the remnants of these 



rock outcrops still exist and provide attractive areas for 

 grazing animals, they are also sites that have had less 

 opportunity for soil development. Because of these condi- 

 tions, the potential for injury or mortality to tree seed- 

 lings from nonanimal and animal sources is higher than on 

 the steeper, more favorable sites. 



Pocket gophers were the greatest cause of tree damage 

 in the study. It appeared that the greatest damage oc- 

 curred on sites receiving the least grazing, where over 

 half of the damage occurred aboveground during the 

 growing season. The most favorable habitat for pocket 

 gophers existed on the sites receiving moderate or light 

 levels of utilization. The forbs and grasses provided ade- 

 quate cover for ease of animal movement, as well as 

 ample food for gopher population buildups. The scalps 

 used for planting on the low-utilization sites provided 

 areas for pocket gophers to begin and end tunnels. Thus 

 pocket gopher damage both above and below ground was 

 more extensive on the sites to receive intermediate to low 

 levels of utilization. 



On sites receiving moderate to heavy grazing intensities, 

 pocket gopher damage was confined to the underground 

 portion of the tree seedlings. There appears to be a rela- 

 tionship between the amount of ground cover and the 

 amount of aboveground rodent damage. Sites receiving 

 moderate-to-high grazing intensities appeared to be less 

 conducive for pocket gopher movement, thus incurring less 

 aboveground damage. 



At the end of 1 year, results from this study indicate 

 that the intensity of livestock use can influence tree seed- 

 ling establishment and mortality. While the effects of 

 grazing management practices on tree seedling establish- 

 ment were not tested, it was observed that there was less 

 damage and mortality where rotation grazing was prac- 

 ticed. In addition, it appears that intensity of livestock 

 grazing may influence rodent damage. If in fact there is a 

 relationship between ground cover and rodent damage, 

 prudent livestock grazing may provide an opportunity to 

 further reduce rodent damage. This possibility warrants 

 further investigation. 



5 



