Data from: Drivers of intra-individual spatial variability in methane emissions from tree trunks in upland forest

CH4 emissions from tree trunks in upland forests should be scaled
accurately in order to assess the role of tree trunks in the forest
CH4 budget. As the chambers used to measure emissions cover only
a small part of the tree trunks, it is necessary to understand the
intra-individual spatial variability in trunk CH4 emissions. We
measured trunk CH4 flux at nine locations per individual on four
trees in a cool-temperate upland forest. To appreciate the origin of this
variability and the underlying processes, we also measured the potential
rate of CH4 production and CH4 concentration at sapwood and characterized
wood and bark. Up to 15-fold spatial variation in CH4 fluxes were
observed at the individual level. This variability can be highlighted by
the variation in the sapwood CH4 concentration which was further
explained by the variation in CH4 production rate. The radial
CH4 diffusivity calculated from concentration gradients and
emissions was not related to the measured characteristics of either wood
or bark, raising the question of the diffusion pathway. We emphasized the
importance of sampling trunk CH4 flux at multiple locations on
the surface of a tree trunk to capture spatial variability, a prerequisite
for estimating tree-level CH4 emissions.