Forest-savanna bistability via moisture recycling feedback
The Amazon generates ~50% of its own rainfall via moisture recycling. This creates a positive
feedback: more forest → more evapotranspiration → more rainfall → more forest.
The model dF/dt = F(r(F) − D) − γF(1−F) exhibits bistability.
Rainfall r(F) = r₀ + α·F. At a critical deforestation rate D_c, the forest state disappears
(saddle-node bifurcation). Hysteresis: recovery requires much lower D than the tipping point.