Canadian Forest Service Publications
Stand structure and species composition in chronosequences of forests on southern Vancouver Island. 2002. Blackwell, B.A.; Hedberg, H.A.; Trofymow, J.A. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC. Information Report BC-X-395. 72 p.
Issued by: Pacific Forestry Centre
Catalog ID: 21075
Overstory stand structure was measured in 32 plots in a Canadian Forest Service study on the effects of converting coastal old-growth forest into managed forest. Stand density, tree height, tree diameter at breast height (DBH), crown depth, stem biomass and basal area (BA) of living stems, and density and mass of snags were measured in a chronosequence of three post-harvest stands (R - regeneration (3-8 years); I - immature (25-45 years); M - mature (65-86) years), and O - an old-growth control (> 200 years) at each of eight study sites on Vancouver Island. Four sites were within the very dry CWHxm and four in the very wet CWHvm biogeoclimatic subzones. Results of this study demonstrate that variability and complexity of overstory structure and composition in coastal forests increases with stand age, and that stands on the west side of the island (CWHvm) were more variable and structurally diverse than those on the east side (CWHxm).
Overstory structure attributes collected for Vancouver Island forests in the CWHxm and CWHvm compare favorably to those of others in the Pacific Northwest. However, old-growth plots do not match US Pacific Northwest definitions of old-growth Douglas-fir as well, likely due to regional differences in climate or because chronosequences were on medium to poor sites. Overstory attribute summaries from this study provide some direction for defining old-growth characteristics. However, the variability of many of these attributes is such that more data are required to rationalize a rigorous definition that will withstand scientific and operational scrutiny.