1 f— 

 90 

 80 

 70 

 60 

 50 



DOUGLAS-FIR 



dozer strip 



4-f t scalp 

 2-ft scalp 



« 100 



w 90 



O 



i_ 



o 



a 80 



< 70h 

 > 



> 60 

 DC 

 => 



CO 50 



\ 



PONDEROSA PINE 



4-f t scalp 



dozer strip 



2-ft scalp 



1 00 r 



90 - 



80 - 



70 - 



60 - 



50 



LODGEPOLE PINE 



1975 



1976 



1977 



YEAR 



1978 



Figure 3.— Tree survival during the first 5 years after planting. 

 The lines are averages for the three aspects. 



dozer strip 



4-ft scalp 



2-ft scalp 



19 7 



Causes of Mortality 



More than half the seedling mortality on all three 

 aspects was not identifiable at the time of measurement. 

 The primary cause of unidentified mortality is likely to 

 have been moisture stress due to poor root growth after 

 planting and gopher damage to the root system. 



A 3X3X3 analysis of variance revealed significant 

 differences in the number of seedlings killed by gophers 

 among the different aspects and among species (tables 2 

 and 3). Gopher kill was significantly greater on the 

 northwest aspect than on the northeast (a = 0.01), with 

 the southeast intermediate (fig. 4). Gophers killed signifi- 



cantly more ponderosa pine than lodgepole pine, with 

 Douglas-fir intermediate (a = 0.05). There was no appar- 

 ent relationship between the number of trees killed by 

 gophers and the site preparation treatment. 



Because the northeast aspect was the only unfenced 

 area, it was the only aspect where trees were killed by 

 sheep. During the small amount of grazing, sheep killed 

 20 trees (19 percent of the total mortality on that site), 

 most of which were trampled or browsed. About half the 

 trees killed were Douglas-fir. Ponderosa pine mortality 

 was almost as high, but only three lodgepole pine trees 

 were killed by the sheep. 



4 



