Heavy thinning increased short-term growth while shrinking one dimension of functional diversity
WHAT THE EVIDENCE SAYS
Thirty plots were assigned to control, light thinning (10–15% basal-area removal) or heavy thinning (20–25%), with ten replicates each. After three years, heavy thinning increased species diversity, functional evenness and divergence and raised total-biomass relative growth rate by 66.7% versus controls, while functional richness fell 61.9%. The diversity–productivity relationship also shifted from negative under control/light treatments to positive under heavy thinning.
WHY IT MATTERS / OUR READ
For managers, ‘more diversity’ and ‘more growth’ are not single outcomes. Thinning intensity can move species diversity, trait-space occupancy, structure and productivity in different directions, so the prescription should follow the objective and be evaluated with more than basal-area growth alone.
CAVEATS / UNCERTAINTY
These are three-year responses in one regional forest type and may represent transient post-thinning dynamics rather than a stable endpoint. Higher short-term biomass growth does not establish long-term resilience or biodiversity benefit, and the loss of functional richness is a material tradeoff rather than noise.
SOURCE
BMC Plant Biology
View original evidence ↗
Three years after treatment in a Zhejiang secondary forest, heavy thinning raised species diversity and biomass growth but reduced functional richness—so the management response depends on which objective is being measured.
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