Woody Detritus Density And Density Reduction Factors For Tree Species In The United States

Author : Mikhail A. Yatskov
Publisher :
ISBN 13 :
Total Pages : 336 pages
Book Rating : 4.:/5 (472 download)

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Download or read book A Chronosequence of Wood Decomposition in the Boreal Forests of Russia written by Mikhail A. Yatskov and published by . This book was released on 2000 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coarse woody debris (CWD) decomposition in the Russian boreal forests of the southern taiga zone was studied at four sites located near St. Petersburg in Northwestern Russia, Krasnoyarsk in Eastern Siberia, lrkutsk in the Baikal region, and Khabarovsk in the Russian Far East. This study was part of a broader research project assessing processes associated with accumulation, storage, and release of carbon by woody detritus in the forests of Russia. A five-class system based on CWD visual characteristics was used to separate logs and snags into decay classes and to estimate their wood density. The largest effect on density was associated with decay classes and species. Region and position had minor effects on density. Decay-class specific density showed a gradual decrease from decay class one (least decayed) to decay class five (most decayed) regardless of species and region. Coniferous snags showed no decrease in density at least for the first two decay classes; for birch this decrease was gradual for both logs and snags. Species became more similar in density from decay class one to decay class five. The chronosequence approach was used to study CWD decomposition by determining change in CWD mass over time. Larch (Larix spp.) and white pine (Pinus siberica/koraiensis) logs had lower decomposition rate-constants than other studied species among the regions fluctuating between 0.015 and 0.031 year−1 for larch and 0.015 and 0.019 year−1 for white pine. Birch (Betula pendula) had the highest decomposition rate-constants among all species and regions ranging between 0.042 and 0.078 year-1. No effect of temperature or precipitation on decomposition rates was observed among the studied regions, although globally there is a significant effect of temperature at least for species with non-decay resistant heartwood. The management implications of the project results for increasing carbon storage potential of Russian forests through CWD management were examined. The current carbon store of CWD including all forest covered land and disturbed forestland was estimated to be 4.31 Pg C. Depending on species composition, this store can be either decreased to 1.56 Pg C with all tree species being replaced by birch, the fastest decomposing species, or increased to 8.11 Pg C with all species being replaced by Korean pine, the slowest decomposing species. The magnitude of these changes is substantial when compared to the potential increases in carbon sequestration of 2.02 Pg C associated with other management steps such as establishing plantations on forest and agricultural lands, reducing stand replacement fires, reducing harvest rates and increasing rotation age, increasing stand productivity via silvicultural treatments, and establishing plantations on sands, drained peat bogs, and mine tailings.