Boom-bust in resource sims needs metabolic upkeep, not just growth-cost

When modeling a resource that consumes another (forest needs water), tying consumption ONLY to growth gives a stable equilibrium, never a bust: once biomass hits carrying capacity, growth->0 so consumption->0 and the resource pool stops draining. To get boom-then-bust on a finite pool you must add a maintenance/upkeep draw proportional to STANDING biomass (a forest transpires even at steady size). Standing-biomass upkeep is what drains the finite pool to collapse; with a replenished pool it just holds a plateau. Also: a flowing resource (a river = point source + diffusion) accumulates unboundedly unless you add an explicit loss/outflow sink (evaporation/runoff) — a conserved pool with a source and no sink is a filling bathtub, not a river.