Hamer 



Chapter 17 



Inland Habitat Associations in Western Washington 



Table 1 Definitions and units of measurement for each habitat variable used in the statistical comparison of occupied versus 

 unoccupied murrelet stands in western Washington, 1991-92. A dominant tree was >81 cm diameter at breast height < d.b.h. i 



Variable 



Definition and units of measurement 



Aspect 

 Basal area 

 Canopy closure 

 Canopy height 

 High comp. 

 Low comp. 

 Nest comp. 



Silver fir comp. 

 Sitka spruce comp. 

 Douglas-fir comp. 

 Western red cedar comp. 

 Western hemlock comp. 

 High d.b.h. 

 Low d.b.h. 

 Mean d.b.h. 

 Nest d.b.h. 

 Silver fir d.bJi. 

 Sitka spruce d.b.h. 

 Douglas-fir d.b.h. 

 Western red cedar d.b.h. 

 Western hemlock d.b.h. 

 Mountain hemlock d.b.h. 

 Distance to saltwater 

 Ecozone 

 Elevation 

 Forest zone 



Latitude 

 Mean lichen 



Mean mistletoe 



Mistletoe number 

 Mean moss 

 Percent moss 

 Platforms/ha 

 Platform total 

 Platforms/tree 

 Percent slope 

 Slope position 

 Stem density 



Major aspect of the plot in degrees 



Basal area (m 2 ) of all dominant trees (>81 cm d.b.h.) in a 25-m radius plot 



Percentage of plot occupied by the crowns of live trees over 10 m in height 



Mean tree height (m) of 10 trees measured per plot 



Percent composition of silver fir and mountain hemlock 



Percent composition of Douglas-fir, western hemlock, western red cedar and Sitka spruce 



Percent composition of those tree species selected for nesting by murrelets in Washington and 

 Oregon including Sitka spruce, Douglas-fir, and western hemlock 



Percent composition of silver fir 



Percent composition of Sitka spruce 



Percent composition of Douglas-fir 



Percent composition of western red cedar 



Percent composition of western hemlock 



Mean d.b.h. (cm) of silver fir and mountain hemlock 



Mean d.b.h. (cm) of of Douglas-fir, western hemlock, western red cedar and Sitka spruce 



Mean d.b.h. (cm) of all dominant trees measured per plot 



Mean d.b.h. (cm) of tree species selected for nesting by murrelets in Washington and Oregon 



Mean d.bJi. (cm) of silver fir 



Mean d.b.h. (cm) of Sitka spruce 



Mean d.b.h. (cm) of Douglas-fir 



Mean d.b.h. (cm) of western red cedar 



Mean d.b.h. (cm) of western hemlock 



Mean d.b.h . (cm) of mountain hemlock 



Closest distance (km) from the plot to salt water 



Geographical areas of similar environments (Henderson and others 1989, 1991) 



Plot elevation (m). 



A classification method for determining plant association based on vegetation series of tree species 

 present (Henderson and others 1989, 1991) 



Latitude of the plot to the nearest minute 



The mean amount of lichen per plot based on an index of lichen coverage on the limbs of all 

 dominant trees 



The mean amount of mistletoe per plot based on an index of mistletoe abundance 

 (Hawksworth 1977) 



The total number of trees/hectare infected with mistletoe 



An index of moss coverage on the platforms of all dominant trees 



The percent moss coverage on the limbs of all dominant trees in a plot 



The total number of potential nest platforms/ha over 15 m in height and 18 cm in diameter 



The total number of platforms from all dominant trees measured within and outside the plot 



Mean number of potential nest platforms per tree 



Percent slope of plot 



Position of stand on slope: (1) lower 1/3; (2) middle 1/3; and (3) upper 1/3 



The number of dominant trees/hectare 



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



165 



