Carbon fractions in the world's dead wood.

Affiliation

Martin AR(1), Domke GM(2), Doraisami M(3), Thomas SC(4).
Author information:
(1)Department of Physical and Environmental Sciences, University of Toronto Scarborough, Scarborough, ON, Canada. [Email]
(2)USDA Forest Service, Northern Research Station, St. Paul, MN, USA.
(3)Department of Physical and Environmental Sciences, University of Toronto Scarborough, Scarborough, ON, Canada.
(4)Institute of Forestry and Conservation, Daniels Faculty of Architecture, Landscape, and Design, University of Toronto, Toronto, ON, Canada.

Abstract

A key uncertainty in quantifying dead wood carbon (C) stocks-which comprise ~8% of total forest C pools globally-is a lack of accurate dead wood C fractions (CFs) that are employed to convert dead woody biomass into C. Most C estimation protocols utilize a default dead wood CF of 50%, but live tree studies suggest this value is an over-estimate. Here, we compile and analyze a global database of dead wood CFs in trees, showing that dead wood CFs average 48.5% across forests, deviating significantly from 50%, and varying systematically among biomes, taxonomic divisions, tissue types, and decay classes. Utilizing data-driven dead wood CFs in tropical forests alone may correct systematic overestimates in dead wood C stocks of ~3.0 Pg C: an estimate approaching nearly the entire dead wood C pool in the temperate forest biome. We provide for the first time, robust empirical dead wood CFs to inform global forest C estimation.