Burial of downed deadwood is strongly affected by log attributes, forest ground vegetation, edaphic conditions, and climate zones

Abstract

Deadwood can represent a substantial portion of forest ecosystem carbon stocks and is often reported following good practice guidance associated with national greenhouse gas inventories. In high-latitude forest ecosystems, a substantial proportion of downed deadwood is overgrown by ground vegetation and buried in the humus layer. Such burial obfuscates the important process of deadwood carbon transfer to other pools (e.g., litter and soil) and emission to the atmosphere (i.e., rates of decay). Using data from the Swedish National Forest Inventory, we found that the proportion of downed logs that is buried increased from temperate to boreal forests. Several factors affect the probability of burial, including log attributes (e.g., decay class), ground vegetation (e.g., moss dominance, type of moss cover), and edaphic conditions (e.g., soil type, depth of organic layer). Combined assessments suggest that about 24% of the carbon in the aboveground downed deadwood pool was found to be buried in boreal forests. Deadwood burial has important implications for forest carbon dynamics and associated monitoring (e.g., United Nations Framework Convention on Climate Change reporting) as such a pool typically decomposes much slower compared with aboveground deadwood.