Miller and Ralph 



Chapter 20 



Inland Habitat Relationships in California 



Marbled Murrelet 

 Survey Stations - 1993 



Prairie Creek 

 State Park 



Tributary drainage 

 Major drainage 



General slope 



Minor ridge 

 ~* Major ridge 

 Occupied site 



Figure 2 Spatial and topographical distribution of a subset of Marbted Murretet stations surveyed 

 at Prairie Creek Redwoods State Park during the summer of 1993. Occupied sites are shaded in 

 groups to illustrate possible associations with topographical features. 





Stand area, perimeter length, and distance from salt 

 water were derived from the CIS database. For stands with 

 inclusions of non-forested area within the stand, we added 

 the length of the lines around the stand and around the 

 inclusions for the total perimeter measurements. Perimeter, 

 therefore, is a measure of the amount of forest edge in and 

 around the stand. 



Stand type was characterized as residual or old-growth. 

 This variable is a measure of harvest history for the stand, 

 but is not a direct measure of years since the last disturbance. 

 Old-growth stands contained trees greater than 90 cm diameter 

 at breast height (d.b.h.) with no history of timber harvest and 

 some evidence of decadence in the canopy. Residual stands 



had some history of partial removal of large trees with the 

 remaining dominant trees greater than 90 cm d.b.h.. Some 

 stands with contiguous areas of old-growth and residual 

 were classified as mixed. 



Stands also were classified by density as determined by 

 interpretation of aerial photographs. Density was defined as 

 the percent of the old-growth canopy cover (dominant and 

 codominant trees): sparse, <25 percent; low, 25-50 percent; 

 moderate, 51-75 percent; and dense, >75 percent Species of 

 dominant trees (>50 percent) was determined from aerial 

 photography and verified by vegetation information after 

 visiting the stand. For the purpose of this study, a stand was 

 a single, isolated group of old-growth trees surrounded by 



USDA Forest Service Gen. Tech. Rep. PS W- 152. 1995. 



207 



