ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

Shrub volume was determ i ned by measuring two hori zontal dimens ions and the height
to the top of each shrub crown in the sample. Vo lume was calculate d from these three
dimensions, considering the shrub an el 1 i pse. Because different shrub species occupy
varying height strata, some shrubs were partially or entirely under the crowns of
taller shrubs. Where this layering occurred (common in larchlfir forests), shrub
volume summaries can appear unrealistically high. Thus, by definition in this study,
cubic shrub volume is aerial crown area X total height of the shrub.
Cover was defined as any forest floor component that covers the mineral soil,
including primarily small shrubs less than 0.5 m (1.6 feet) tall , all herbaceous
vegetation, and down woody material .
Biomass equivalents were determined for shrubs by collecting representative samples
of major species in areas adjacent to the permanent sample plots and then breaking the
shrubs into three components--leaves, stems less than 4-mm (0.16-i nch) diameter, and
stems more than 4 mm (0.16 inch), Regressions were developed to relate these biomass
values before and after treatments to volumes measured on the permanent plots (fig. 4).
Figure 4. --Researchers co Llect representat.i-z)c sump Les 01 shrub vegetation to determine
the reZationship of shrub biomass to volume.