Stand biomass, productivity and their stability
The biomass of each (sub)plot, from 400 to 2500 m2,
was calculated by summing the total biomass (stem + branches + foliage +
roots) for each tree, which was estimated using the allometric equations
that were separately developed for each forest type (Table S1). Annual
biomass increment was calculated as the difference in stand biomass
between two adjacent years (△B = Bt -
Bt-1, where Bt is the stand biomass of
the current year). Noted that △B does not include litterfall production
and thus is a part of net primary productivity, however, for simplicity
in narration we abbreviated it as productivity hereafter.
To analyze the relationship between diversity and ecosystem functions,
we calculated the multi-year mean
biomass (2004-2010) and productivity (2005-2010) for each plot
(subplot). To explore the effect of diversity on ecosystem stability, we
calculated the temporal stability index (Tilman et al. 2006; van
der Plas 2019) based on the annual biomass and productivity data for
each (sub)plot. Temporal stability is a measure of how community
productivity (biomass) fluctuates around its multi-year means: S = 1 /
CV = υ/б, where υ is the mean value for a time period andб is the standard deviation over the same interval, while CV is
the coefficient of variation (Tilman et al. 2006; van der Plas
2019). Hereafter, the stability of biomass and productivity are
abbreviated as S_B, S_P, respectively.