Fig. 1

Illustration of how selective harvesting may influence two diversity-dependent (a, b) and a size-dependent (c) regulatory mechanisms of the temporal stability of aboveground biomass productivity in multi-layered mixed forests. The width of the top arrows in each graph reflects the magnitude of the effects. In part a, along the gradient of increasing harvesting intensity (decreasing stand density), the magnitude of species complementarity for biomass production may show a decreasing (dashed blue line). These changes of complementarity further alter the overyielding effect. Part (b) shows how species with different shade tolerances and growth strategies respond to harvesting treatment. The solid lines indicate increased abundance of a pioneer (yellow) and a subordinate light-demanding (blue) tree species, while the dashed line indicates a decrease in the abundance of subcanopy shade-tolerate species (orange). The canopy dominant trees (green) do not show strong reactions (dotted green line). Such changes in community composition may modify the overall asynchronous species dynamics at the community level. Red X indicates tree mortality. Part c shows that selective harvesting reduces the degree of size-asymmetric resource competitions, benefiting the growth of small-sized trees (solid line) over large trees (dashed line), as indicated by a decline in the growth dominance coefficient (GDC)