ANCILLARY DATA - METHODS AND CAVEATS
Ancillary
data are summarized for each wildlife habitat type, but are not divided by
subregion or structural condition class.
Figures and Tables are referred to with an "*" followed by
".sp-" and a figure or table number. In the summary narratives
the "*" is replaced by the wildlife
habitat code (e.g., WLCH). The methods and caveats for each figure and
table number apply to all wildlife habitat types.
Tree height
When it was possible to distinguish the height of dead trees used from live trees, only heights of snag species were tabulated. However, many studies did not do this, so heights of live trees are included in this analysis. When we discuss tree height here, we mean the total height of the tree, not the height at which the observed activity of the wildlife species occurred.Within a habitat type, a weighted mean height was calculated for all records of the same species with the same use (e.g. nesting, foraging, etc). Means were weighted by sample size. These means were then graphically displayed within each habitat type (Figure *.sp-11).
Tree species
When reviewed papers indicated the species of snags or trees used by wildlife, these species were recorded by frequency of use, if possible. When it was possible to distinguish the species of dead trees used from live trees, only snag species were tabulated. Many studies did not do this however, so there are species of live trees included in this analysis. In Table *.sp-1, the tree species used most often was noted under the column “Species 1". The tree species used second most often was noted under the column “Species 2", and so on through “Species 4". If studies indicated selection, then tree species were recorded in order of selection rather than frequency. Some studies showed only a single tree species used; in those cases, it wasn’t always clear whether that was the only species used, or just the species most often used.Data records for the same species having the same use were combined within each habitat type (Table *.sp-2). The species and their use were displayed with all the tree species used within a habitat type. Letters in Table *.sp-2 represent the frequency of use of a tree species by a particular wildlife species. A "P" indicates data records where a wildlife species used that particular tree species most often, or primary use. An "S" indicates data records where a wildlife species used that tree species second most often within that particular study, or secondary use. An "L" indicates wildlife species use of a tree species that was to some lesser degree. The number of wildlife species using individual tree species within a particular habitat type is summarized in Figure *.sp-12.
Tree mortality condition
Where studies of wildlife species use of trees indicated the proportion of trees that were live or dead, this was recorded and further analyzed (Table *.sp-3). Some studies may have only looked at snag use by wildlife species, and would therefore not have recorded any live tree use. This was probably particularly true of earlier studies. We did not attempt to distinguish those studies from others, so studies that showed 100% use of either live or dead trees may be more a reflection on the study design rather than a reflection of species use. Our main point in this section was to see whether live trees, especially dead or decayed portions of live trees, may also be important habitat features for certain species or certain life stages of a species.Hollow live trees and snags
Where hollow trees were noted in studies, these data were recorded (Table *.sp-4). Very few studies addressed wildlife use of hollow trees and snags.Snag decay
The studies we reviewed used a wide array of methodologies to classify the decay stage of snags. The classification schemes used had from two to nine categories of snag decay. In order to compare decay stages across studies, we took all the snag categories and, based on the author’s description of these categories, re-classed the snags as either soft, moderate or hard, similar to Bull et al.’s (1997) classification scheme (Table *.sp-5).Tree top condition
If the studies we reviewed noted whether or not the top of the tree was broken out or intact, we recorded that information (Table *.sp-6). When available, we also noted the proportion of the trees in each study that were in the recorded condition.Down wood length
Within a habitat type, a weighted mean length was calculated for all records of the same species with the same use (e.g., nesting, foraging, etc.). Means were weighted by sample size. These means were then graphically displayed within each habitat type (Figure *.sp-13).Down wood species
When reviewed papers indicated the species of down wood used by wildlife, these species were recorded by order of use, if possible. The down wood species used most often was noted under the column “Species 1" in Table *.sp-7. The down wood species used second most often was noted under the column “Species 2", and so on through “Species 4". If studies indicated selection, then down wood species were recorded in order of selection rather than frequency. Some studies showed only a single down wood species used; in those cases, it wasn’t always clear whether that was the only species used, or just the species most often used.Data records for the same species having the same use were combined within each habitat type (Table *.sp-8). The species and their use were displayed with all the down wood species used within a habitat type. Letters in Table *.sp-8 represent the frequency of use of a down wood species by a particular wildlife species. A "P" indicates data records where a wildlife species used that particular down wood species most often, or primary use. An "S" indicates data records where a wildlife species used that down wood species second most often within that particular study, or secondary use. An "L" indicates wildlife species use of a down wood species that was to some lesser degree. The number of wildlife species using individual down wood species within a particular habitat type is summarized in Figure *.sp-14.