From canopy complementarity to asymmetric competition: the negative relationship between structural diversity and productivity during succession

1. Positive relationships between structural diversity and forest productivity have been documented in controlled experiments and early secondary forests, however, negative relationships have also been observed in late successional forests. The mechanisms causing observed relationships between structural diversity and productivity are not well established, but complementarity among crowns and asymmetric competition have been suggested.

2. We used LiDAR and repeated census data to examine relationship between canopy structural diversity and productivity in nine 1-ha subtropical forest plots along a disturbance gradient in southeastern China. We quantified the relative importance of community composition, species diversity, canopy structural diversity, leaf area index (LAI), and disturbance regime on productivity using piecewise structural equation modelling. We also tested how vertical leaf area distribution effected productivity.

3. Contrary to many prior observations, we found a ...