Canadian Forest Service Publications
13C CPMAS NMR spectroscopy and chemical analysis of coarse woody debris in coastal forests of Vancouver Island. 1998. Preston, C.M; Trofymow, J.A.; Niu, J.; Fyfe, C.A. Forest Ecology and Management 111: 51-68.
Issued by: Pacific Forestry Centre
Catalog ID: 5121
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The coastal forests of British Columbia have large accumulations of coarse woody debris, and information on this pool is considered essential in developing sustainable management practices. We characterized coarse woody debris (7-12 and >12 cm diameter) in forest chronosequences of four age classes located on east and west sides of Vancouver Island. For three species (Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg), western redcedar (Thuja plicata Donn.)) and unidentifed samples, increases in decay class (I to V, assigned in the field) were associated with decreasing density, and small increases in concentrations of C, N, and P. Sulfur concentrations (0.6 to 2.4 g/kg) were higher than those found elsewhere for wood and did not show any significant changes with decay class. Carbon-13 nuclear magnetic resonance spectroscopy with cross polarization and magic-angle spinning (13C CPMAS NMR) was used to analyse organic components in a subset of samples >12 cm. Logs up to decay class III generally showed little change in composition or a slight increase in polysaccharide C. After this, polysaccharide was lost more quickly and logs of decay class V were composed almost entirely of lignin, a pattern consistent with decay by brown-rot fungi. However, two samples of western redcedar decay class III and IV showed accumulation of polysaccharide, the pattern expected from white-rot fungi. The results of the density, chemical and NMR analysis indicate that for management purposes, a system with fewer decay classes would suffice.