Data from: Soil moisture mediates the effect of plant belowground carbon allocation on the decomposition of root litter in a subtropical forest

Trees allocate carbon belowground to fuel the functioning of roots and
mycorrhizal fungi, which affect litter decomposition, but the direction
and magnitude of this effect are variable. While tree mycorrhizal type is
often suggested to mediate this aboveground-belowground linkage, previous
studies yield mixed results. In this study we investigated how absorptive
root traits, soil conditions and litter type influence the response of
litter decomposition to altered belowground carbon allocation, both within
and across mycorrhizal types. We girdled transport roots of seven
subtropical tree species to eliminate carbon allocation to distal
absorptive roots. We monitored leaf and root litter decomposition
surrounding girdled and un-girdled root branches. We found that girdling
generally slowed leaf litter decomposition. However, the effect of
girdling on root litter decomposition depended on soil moisture,
stimulating decomposition in dry soil but suppressing it in moist soil.
Absorptive root traits did not influence the girdling effect on either
leaf or root litter decomposition. These findings suggest that disturbance
in carbon allocation can impact litter decomposition, with the outcome
largely contingent on litter type and soil moisture. Synthesis. Our
findings highlight the importance of accounting for local soil variability
in understanding the relationship between aboveground and belowground
carbon dynamics. This study underscores a critical need for comprehensive
assessment of belowground ecosystem responses to aboveground disturbances,
as it is essential for accurately predicting future forest carbon and
nutrient cycles.