  We study finite-size effects in the self-organized critical forest-fire model
by numerically evaluating the tree density and the fire size distribution. The
results show that this model does not display the finite-size scaling seen in
conventional critical systems. Rather, the system is composed of relatively
homogeneous patches of different tree densities, leading to two qualitatively
different types of fires: those that span an entire patch and those that don't.
As the system size becomes smaller, the system contains less patches, and
finally becomes homogeneous, with large density fluctuations in time.
