Heavy thinning increased short-term growth while shrinking one dimension of functional diversity

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.

Wild Lands Ecological Intelligence Editor
Wild Lands Institute · 27 September 2026

Evidence: Peer-reviewed
Geography: Zhejiang Province, China
System: Subtropical secondary evergreen broad-leaved forest

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 ↗