A chronosequence of wood decomposition in the boreal forests of Russia

Coarse woody debris (CWD), represented by logs and snags >10 cm in diameter and >1 m in length, was sampled at eight sites in Russian boreal forests to determine the specific density of decay classes and decomposition rates. Tree species sampled included Abies siberica Ledeb., Betula pendula Roth., Betula costata Trautv., Larix siberica Ledeb., Larix dahurica Turcz., Picea abies (L.) Karst., Picea obovata Ledeb., Picea ajanensis Fisch., Pinus koraiensis Sieb. et Zucc., Pinus siberica Ledeb., Pinus sylvestris L., and Populus tremula L. The mean densities for decay classes I through 5 ranged from 0.516 to 0.084 g-cm(-3) respectively. Annual decomposition rates varied among the species, and for logs, decomposition rates ranged from 4.2 to 7.8% for B. pendula, 2.6 to 4.9% for Picea spp., 2.7 to 4.4% for Pinus sylvestris, 1.5 to 3.1% for Larix spp., and 1.5 to 1.9% for Pinus koraiensis and Pinus siberica. Logs decomposed faster than snags. Among the sites examined, temperature and precipitation did not correlate with decomposition rates, which is consistent with other studies in the boreal region. Globally, a positive correlation between decomposition and mean annual temperatures was found, with decay-resistant trees less responsive than those with low decay resistance.