Decomposition and carbon loss in lodgepole pine (Pinus contorta var. latifolia) wood following attack by mountain pine beetle (Dendroctonus ponderosae)

摘要

Mountain pine beetle (MPB)-killed wood remaining on the landscape is predicted to release significant amounts of carbon to the atmosphere as it decays. A lack of field-based wood decomposition data for validating simulation models reduces certainty in such predictions. Using a chronosequence approach, I quantified decomposition of MPB-killed wood to improve decay rate parameters. Changes in carbon density over time and climatic variability showed distinct patterns for bole position categories. Snag carbon density was similar to that of live lodgepole pine, and did not change considerably with time or climatic influences. Decay in suspended boles increased with summer precipitation, but declined with increasing summer temperature, suggesting decay in elevated boles is moisture-limited on warmer sites. Down boles decayed four times faster with increasing proximity to the soil than suspended boles, but did not clearly reflect climatic influences. Position of dead boles appears more important for wood decay than previously thought. --Leaf ii.