same number of trees, regardless of competition. We apparently need to strike a bal- 

 ance between vegetation left for protection against sun and wind, and vegetation 

 removed to increase available water, light, and nutrients. This balance point is 

 expected to differ with habitat and amount of logging debris left on the site. 



Shade. --kn important factor affecting survival of young Douglas-fir trees is the 

 portion of daylight hours during which a tree is shaded. Only on western hemlock 

 habitats were more trees found out in the open than where they received shade during 

 part of the day (fig. 10). On all other habitats, more Douglas-fir trees were found 

 under partial shade. 



Shade was often from the surrounding stand, but not always. Sometimes logging 

 debris, shrubs, and forbs offered protection, especially in clearcuts where debris had 

 not been piled and burned. 



The major benefit from shade is believed to be the amelioration of temperature and 

 moisture extremes. The intensity of the light itself does not appear to limit the 

 growth of trees in this area. 



Distance from stand edge . --Most natural seedlings of Douglas-fir were found within 

 1 chain of the stand edge on Douglas-fir habitats. Milacre stocking decreased from 57 

 percent close to the stand edge to 9 percent at 4 chains or more into the opening. 

 However, proximity to stand edge was not necessary for seedling establishment on moister 

 habitats. For instance, milacre stocking on the western hemlock habitat averaged 65 

 percent close to the stand edge, but increased to 77 percent at distances of 1 to 3 

 chains from the edge. Larger openings relying on natural regeneration were not found 

 in this habitat. 



Figure 10, — More planted Douglas-fir trees 

 they received direct sunlight throughout 

 during some portion of the day seemed to 



survived on the western hemlock habitat when 

 the day. On the other habitats, shade 

 increase survival. 



13 



