Data from: Biomass production of tropical trees across space and time: The shifting roles of diameter growth and wood density

Woody biomass in tropical trees contributes significantly to global carbon
stocks; however, these stocks are increasingly affected by climate and
land-use changes. Understanding the growth mechanisms driving woody
biomass production is essential for assessing the short- and long-term
contributions to carbon stocks and dynamics in tropical forests. Trees
accumulate biomass by increasing their size (wood volume) and/or tissue
density (wood density). However, estimates of tree biomass production are
often based solely on size increment through measurements of stem diameter
growth, overlooking the potential spatial and temporal variation in wood
density within trees. Tree-ring analysis can be applied to reconstruct
past tree volume growth and wood density variations, allowing the
quantification of their relative contributions when reconstructing past
woody biomass production. Here, we studied trees of the widespread
Neotropical genus Cedrela (C. fissilis, C. odorata, and C. montana) along
an environmental (climate and soil) gradient to address two key questions:
1) How does temporal variation in tree diameter growth and wood density
affect biomass production? 2) To what extent do these relationships vary
along the environmental gradient? We examined long-term (ontogenetic,
variation from pit to bark) and short-term (annual, interannual variation)
variations in diameter growth and wood density, covering eighteen sites in
the Amazon rainforest, Atlantic Forest, Cerrado savanna, and Caatinga dry
forest. We found that diameter growth and wood density drive short- and
long-term biomass production dynamics. Interestingly, diameter growth
patterns predominantly explained short-term variability in biomass
production at all sites, whereas wood density explained ontogenetic
biomass patterns mainly at humid sites. These results highlight the
importance of accounting for both short- and long-term variation,
including climatic and ontogenetic drivers, to increase the accuracy of
biomass estimations in tropical trees, particularly in humid forest
ecosystems such as the Amazon.  Diameter growth is an important
and good indicator of forest carbon production. However, size-related
changes in wood density, which are usually neglected, are critical for
accurate short- and long-term carbon assessments, especially in tropical
humid sites.