Grenier and Nelson Chapter 19 Inland Habitat Associations in Oregon 



Table 4 Overall habitat characteristics of occupied stands, Oregon Coast Range, 1992 



1 Position on Slope: 1 = canyon bottom, 2 = lower 1/3, 3 = middle 1/3, 4 = upper 1/3, 5 = ridge top. 



2 Moss Index: = none, 1 = trace, 2 = 1-24 percent, 3 = 25-49 percent, 4 = 50-100 percent. 



3 Mistletoe Abundance: Divide tree into thirds. Rate each section; for no mistletoe, 1 if less than 1/3 of branches 

 are infected, and 2 if more than 1/3 are infected. Score range is 0-6. 



81.4 cm (s.e. = 7.4). Mistletoe and witches brooms were 

 found on dominant trees in most stands. Nests were located 

 between 1 .6 and 40 km from the ocean. 



Three habitat variables at 10 nest sites differed from 

 adjacent plots (table 6). The density of live trees in the 

 largest size class (d.b.h. >81 cm) was greater in adjacent 

 plots than in nest plots (64.3 versus 43.3 trees/ha; P = 0.03). 

 Snag height was greater and snags were less decayed in 

 adjacent plots compared with nest plots (15.5 versus 7.5 m; 

 P = 0.03; 3.3 versus 3.7; P < 0.001, respectively). In addition, 

 canopy closure was marginally greater in adjacent plots than 

 nest plots (61.3 percent versus 41.2 percent, P = 0.06). 



Discussion 



Occupied Sites 



In Oregon, sites occupied by Marbled Murrelets were 

 characterized by large diameter conifers and hardwoods, tall 

 trees, high densities of dominant trees, and low densities for 

 small diameter trees (conifers and hardwoods combined). In 

 addition, these sites were older, located on gentler slopes, 

 and had less percent canopy cover than random sites. Important 

 habitat components for predicting occupancy were height 

 and density of dominant trees, diameter and percent cover of 

 midstory and understory conifers, and canopy cover. 



198 



USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 



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