Data from: Understanding the recruitment response of juvenile Neotropical trees to logging intensity using functional traits

Selective-logging remains a widespread practice in tropical forests, yet
the long-term effects of timber-harvest on juvenile tree (i.e., sapling)
recruitment across the hundreds of species occurring in most tropical
forests, remain difficult to predict. This uncertainty could potentially
exacerbate threats to some of the thousands of timber-valuable tree
species in the Amazon. Our objective was to determine to what extent
long-term responses of tree species regeneration in logged forests can be
explained by their functional traits. We integrate functional trait data
for 13 leaf, stem, and seed traits from 25 canopy tree species with a
range of life histories, such as the pioneer Goupia glabra and the
shade-tolerant Iryanthera hostmannii, together with over 30-years of
sapling monitoring in permanent plots spanning a gradient of harvest
intensity at the Paracou Forest Disturbance Experiment (PFDE), French
Guiana. We anticipated that more-intensive logging would increase
recruitment of pioneer species with higher specific leaf area, lower wood
densities, and smaller seeds, due to the removal of canopy trees. We
define a recruitment response metric, to compare recruitment responses to
timber-harvest intensity across species. Although not statistically
significant, sapling recruitment decreased with logging intensity for
eight of 23 species, and these species tended to have large seeds and
dense wood. A generalized linear mixed model fit using specific leaf area,
seed mass, and twig density data explained about 45 percent of the
variability in sapling dynamics. Effects of specific leaf area outweighed
those of seed mass and wood density in explaining recruitment dynamics of
the sapling community in response to increasing logging intensity. The
most intense treatment at the PFDE, which includes stand-thinning of
non-timber-valuable adult trees and poison-girdling for competitive
release, showed evidence of shifting community composition in sapling
regeneration at the 30-year mark, toward species with less dense wood,
lighter seeds, and higher specific leaf area. Our results indicate that
high-intensity logging can have lasting effects on stand regeneration
dynamics and that functional traits can help simplify general trends of
sapling recruitment for highly-diverse logged tropical forests.