Harvesting and climate effects on organic matter characteristics in British Columbia coastal forests

• Published in: Journal of environmental quality Vol. 31; no. 2; pp. 402 - 413
• Main Authors: PRESTON, C. M, TROFYMOW, J. A, NIU, J, FYFE, C. A
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Madison, WI Crop Science Society of America 01-03-2002; American Society of Agronomy
• Subjects: Astringents - analysis; British Columbia; Carbon 13; Charcoal; Climate; Climate effects; Earth sciences; Earth, ocean, space; Environmental Monitoring; Exact sciences and technology; Forest floor; Forestry; Geochemistry; Hydrolyzable Tannins - analysis; NMR; Nuclear magnetic resonance; Organic Chemicals - analysis; Organic matter; Principal components analysis; Roots; Soil; Soil and rock geochemistry; Soils; Surficial geology; Vancouver Island; Canada; British Columbia; Western Canada; climate effects; carbon; organic materials; NMR spectra; soils; North America; forests; nuclear magnetic resonance; principal components analysis; organic carbon; coastal environment
• ISSN: 0047-2425; 1537-2537; 1537-2537
• DOI: 10.2134/jeq2002.0402

As part of investigations into the effects of harvesting old-growth forest, we characterized carbon in five organic matter pools in eight forest chronosequences of coastal British Columbia. Each chronosequence comprised stands in four seral stages from regeneration (3-8 yr) to old-growth (>250 yr), with second-growth stands mostly of harvest origin. Stands were located in two biogeoclimatic subzones with contrasting climate (wetter, slightly cooler conditions on the west coast of Vancouver Island than on the east). Carbon concentrations in fine woody debris (FWD), forest floor (LFH), fine roots from LFH, and two water-floatable fractions from 10 to 30 cm mineral soil (MIN-ROOT, 2-8 mm and MIN-FLOAT, <2 mm) showed no significant effects due to climate, seral stage, or site. There were some significant differences in N concentrations, but none related to seral stage. Carbon-13 cross-polarization with magic-angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectra with principal component analysis of relative areas also showed little harvesting effect, but greater variation related to input of coarse woody debris (CWD) vs. roots high in tannin. Overall, there tended to be more spectral features associated with wood and lignin in the west; whereas some MIN-ROOT samples from the drier east side had aromatic intensity attributed to charcoal. The minimal effects of one harvest on organic matter are most likely due to the large legacy effect; however, more intensive management will probably result in less CWD retention, less charcoal input, and less microsite variability in these pools of poorly decomposed organic matter.