Data from: Fine root presence and increased phosphorus availability stimulate wood decay in a Central Amazonian rainforest

In the Amazon basin, approximately 60% of rainforest thrives on
geologically old and highly weathered soils, thus decomposition represents
an important mechanism for recycling nutrients from organic matter.
Although dead logs and branches constitute up to 14% of the carbon stored
in terrestrial ecosystems, woody debris decomposition and mainly the
effect of direct nutrient cycling by plant root interaction is poorly
studied and often overlooked in ecosystem carbon and nutrient budgets.
Here we monitored the decomposition of five different local woody species
covering a range of wood density by conducting a long-term wood
decomposition experiment over two years with factorial root presence and
phosphorous (P) addition treatments in a Central Amazonian rainforest. We
hypothesized that woody debris decomposition is accelerated by colonizing
fine roots mining for nutrients, possibly strongly affecting wood debris
with lower density and higher nutrient concentration (P). We found that
root colonization and P addition separately increased wood decay rates,
and although fine root colonization increased when P was added, this did
not result in a change in wood decay. Nutrient loss from wood was
accelerated by P addition, whereas a root presence effect on nutrient
mobilization was only detectable at the end of the experiment. Our results
highlight the role of fine roots in priming wood decay, although direct
nutrient acquisition by plants seems to only occur in more advanced stages
of decomposition. On the other hand, the positive effect of P addition may
indicate that microbial nutrient mobilization in woody material is driven
mainly by wood stoichiometry rather than priming by root activity.