Figure 4.3: An example
of net changes in ecosystem carbon stocks over time. Changes in individual ecosystem
components take place at different rates, but it is the net of the changes in
all interconnected pools that determines the net flow to or from the atmosphere.
In the example, the accumulation of biomass initially is at a lower rate than
the decomposition of the dead organic matter stock so the stock of ecosystem C
declines. Later in the cycle, dead organic matter stocks may increase, although
other components have reached a steady state. Maximum ecosystem stocks (highest
value of ecosystem C) occur at a later time than the maximum rate of net carbon
uptake (steepest slope of the ecosystem C line).