Grenier and Nelson 



Chapter 19 



Inland Habitat Associations in Oregon 



that survived recent fires and were >66 cm d.b.h., except in 

 one Forest Service database where remnant trees were 

 classified as >100 cm d.b.h.. 



State Lands Database 



Data were compiled from Oregon Department of 

 Forestry's (ODF) OSCUR Inventory System (Ownership, 

 Soils, forest Cover, land t/se, and operation /fating). The 

 OSCUR database was comprised of habitat variables 

 collected between the mid-1970s and 1993 (appendix 1). 

 ODF delineated and described habitat characteristics in 

 forest sites through one of the following: (1) photographic 

 interpretation; (2) stand examinations (fixed plot cruising, 

 variable plot inventory, or timber sale appraisal); and (3) 

 reconnaissance (walk-through) (ODF 1991). The OSCUR 

 database included data from 6,409 sites. A site was defined 

 as a uniform, homogeneous tree community that usually 

 was a portion of a larger, contiguous, heterogeneous stand. 

 Sites were characterized by approximately 160 habitat 

 and geographic variables. In addition, comments from 

 original data sheets were included to supplement data for 

 some sites. 



We selected 34 key habitat variables (appendix 2) and 

 forest sites >40 years old for analyses. Sites of this age were 

 chosen because the youngest occupied site on state lands 

 was classified as 42 years old (although the site included 

 remnant old-growth trees). In addition, we were interested in 

 examining differences of habitat characteristics between 

 occupied and random sites within a sample universe of only 

 suitable habitat i.e., sites containing large trees with adequate 

 branch sizes and moss coverage to accommodate nesting 

 (Grenier and Nelson 1994). Using maps and databases, we 

 found that 72 occupied sites existed on ODF lands (Allen, 

 pers. comm; Goggans, pers. comm.; Nelson 1990b; Nelson 

 and Shaughnessy 1992; Platt and Goggans 1992; Shaughnessy 

 and Nelson 1991). Characteristics of these 72 occupied sites 

 were compared to a random sample of 216 sites of unknown 

 murrelet status. 



National Forest Land Databases 



Vegetation Resource and Structure Examination 

 Databases (VSE) Older-aged forests or those with multiple 

 canopy layers were monitered on the Siuslaw National Forest 

 in 1990. These study sites were located in areas proposed for 

 timber harvest and in Northern Spotted Owl (Strix occiden- 

 talis) Habitat Areas. In addition, Vegetation Resource 

 Examinations (VRE) were conducted in 1991 and 1992 to 

 ground truth satellite imagery of old-growth and mature 

 forests with multi-layered canopies. Overlapping data from 

 the two databases (1209 VRE and 1210 VSE plots) were 

 used for analyses. Forty-seven habitat variables were common 

 to both databases (appendix 2). Data from 120 sites (Wettstein, 

 pers. comm.), 30 occupied sites and 90 other sites of unknown 

 murrelet status, were used for analyses. 



Ecological Habitat Sampling Ecologists at the Siuslaw 

 National Forest collected habitat data in intensive and 



reconnaissance plots throughout the forest from 1981 to 

 1984 (Hemstrom and Logan 1986; USDA 1983, 1985). The 

 database provided to us included 974 forested sites and 162 

 habitat variables (McCain, pers. comm.). We used ArcView 

 (1992) to determine that 75 occupied sites overlapped with 

 plots in this database. We selected 13 of the 162 habitat 

 variables for our analyses (appendix 3). To be consistent 

 with the ODF database, we used data from sites >40 years 

 old. The characteristics of the 75 occupied sites were 

 compared with a random sample of 225 sites of unknown 

 murrelet status. 



Research Database 



In 1992, 40 small (<12 ha), isolated, mature and old- 

 growth stands were selected (Nelson and Hardin 1993a). 

 Using protocol surveys, we determined that 10 of these 

 stands were occupied. Habitat characteristics were measured 

 in two 25-m-radius circular plots randomly located within 

 each of these stands. Variables included number of trees and 

 snags by species, tree and snag diameter at breast height 

 (d.b.h.), heights (m) of five dominant conifers (measured by 

 triangulation with a Suunto optical clinometer), height (m) 

 and decay class of snags (Cline and others 1980), forest zone 

 (Franklin and Dyrness 1973), ecozone (average precipitation 

 levels), plant associations (Hemstrom and Logan 1986), 

 number of canopy layers, canopy cover (visual estimate of 

 percent crown closure), ground cover (percent and species 

 composition), abundance of moss and dwarf-mistletoe 

 (Arceuthobium sp.), number of suitable nest platforms (> 18 

 cm d.b.h., > 15 m height), slope (percent), aspect (degrees), 

 position on slope (canyon bottom, lower 1/3, middle 1/3, 

 upper 1/3, ridgetop), distance to water (m), and distance to 

 opening (m; opening defined as road, river, clearcut, or 

 vegetation type without trees but not forest gap). Calculations 

 made from these data included density (number/ha) of trees 

 (>46 and <80 cm d.b.h.) and dominant trees (>8 1 cm d.b.h.), 

 mean diameter (d.b.h., cm) of all trees and dominant trees, 

 mean dominant tree height (m), and tree species composition. 

 Percent cover of epiphytes (moss and lichens) were recorded 

 in four categories: (1) trace, (2) 1-33 percent, (3) 34-66 

 percent, (4) 67-100 percent. Average mistletoe infestation 

 was calculated for each plot using an index of to 6 developed 

 by Hawksworth (1977). Distance inland (km), latitude, 

 elevation (m), and stand size (ha) were determined from 

 topographic maps (1:250,000) and aerial photos (1:1,000). 



Nest Site Characteristics 



Nests were located using ground-based and tree climbing 

 techniques, most (15 of 22) in areas where likelihood of 

 finding nests was considered to be high. Ground-based 

 methods consisted of observing the flight of individual birds 

 during dawn and dusk activity periods, and searching for 

 eggshell fragments on the forest floor. Flight behaviors 

 suggesting the presence of nesting birds (e.g., landing in or 

 departing from trees and flying silently below the canopy) 

 were identified at survey stations established in areas where 



192 



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



