By assuming a forest growing logistically and a local population that harvests wood illegally in a manner similar to predation, a bio-economic model gives the following results: 1) when local population is very low, optimal deterring effort is zero; 2) as long as the population is sufficiently low, no deterring effort is required to avoid complete deforestation; 3) when population is above minimum threshold, optimal deterring effort is determined by the cost of deterrence relative to the value of wood; 4) when human population grows above a higher threshold, deterring effort must be greater than zero to avoid complete deforestation; 5) the larger the population grows, minimum deterring effort to avoid exhaustion approaches maximum effort; 6) when human population is very large, the relative cost of deterrence must be low, or the price of wood very high, to make deterrence worth wile.