Seed dispersal patterns and differences in environment contribute to differences 

 in effect of distance from stand edge on seedling establishment. Boe (1953] found the 

 quantity of sound Douglas-fir seed that fell to the ground decreased rapidly from timber 

 edge to about 4 chains. R. C. Shearer (personal communication, research silviculturist, 

 Missoula, Mont.) has found the number of sound seeds required per established tree to 

 differ greatly with changes in habitat. Therefore, on the drier sites the amount of 

 seed reaching the middle of larger openings may not be sufficient for successful 

 regeneration . 



DISCUSSION 



The intention of this survey was to determine where Douglas-fir regeneration prob- 

 lems exist. Admittedly, the results from a quick survey of this type are not conclusive 

 and have a lot of holes. For instance, certain conditions were encountered so seldom 

 in my sample that data are scarce or completely lacking for some categories in the 

 summarization tables. Also, our comparisons of planting success on the basis of per- 

 cent milacre stocking assumes that approximately the same number of trees were planted 

 per acre on all habitats. It also assumes that handling and planting techniques and 

 quality of nursery stock were generally comparable throughout the study area. It is 

 probable that these assumptions have not been met in all cases. 



Nevertheless, I am confident the data are sufficient for the stated purpose. They 

 show us that the success of Douglas-fir regeneration varies with habitat, and that 

 success has been low on sites where Douglas-fir attains climax status. In view of the 

 great diversity of plantation success and of Douglas-fir sites in the Northern Rockies, 

 this seems to be a logical conclusion. It also agrees generally with the results of 

 previous work. 



While studying factors affecting regeneration of western Montana clearcuts, Steele 

 and Pierce (1968) observed that where wildfires have burned over large areas, south 

 aspects are extremely slow to regenerate. They concluded that the south and west ex- 

 posures need special consideration in determining the cutting method to be employed as 

 well as in the treatment of the resulting slash. Larsen (1924) also points out the 

 difficulty of obtaining regeneration on south aspects due to extremes in temperature and 

 drought. These south-aspect sites are often Douglas-fir habitat types. 



boyd (1969) described natural regeneration trends in some northern Idaho western 

 white pine stands. On moist habitats, even-aged silviculture systems resulted in ade- 

 quate regeneration witliin 5 to 10 years. Drier habitats had a prolonged regeneration 

 period, possibly exceeding 20 years, regardless of the silviculture system used. His 

 dry sites were grand fir habitats, which are more moist than the Douglas-fir habitats. 



Results from a recent planting study (manuscript in preparation) also confirm the 

 effect of habitat on plantation success. In a planting test of species adaptation to 

 high-elevation clearcuts, first-year survival was high (90 to 100 percent) on most plots 

 regardless of habitat. By the end of the third year, however, survival was related to 

 habitat types. 



14 



