Implications of the Steady-state Assumption for the Global Vegetation
Vegetation turnover time (τ) is a central ecosystem property to
quantify the global vegetation carbon dynamics. However, our
understanding of vegetation dynamics is hampered by the lack of
long-term observations of the changes in vegetation biomass. Here we
challenge the steady state assumption of τ by using annual changes
in vegetation biomass that derived from remote-sensing observations.
We evaluate the changes in magnitude, spatial patterns, and
uncertainties in vegetation carbon turnover times from 1992 to 2016. We
found that the forest ecosystem is close to a steady state at global
scale, contrasting with the larger differences between τ under steady
state and τ under non-steady state at the grid cell level. The
observation that terrestrial ecosystems are not in a steady state
locally is deemed crucial when studying vegetation dynamics and the
potential response of biomass to disturbance and climatic changes.