“…The resulting variation was richly displayed on the presettlement landscape, wherein annually burned prairies were bounded by a continuum of savannas, open woodlands, and closed-canopy forests with increasing distance (Nuzzo 1986, Anderson 1998, although abrupt prairie-forest transitions did exist along natural firebreaks (e.g., rivers). Similar structural and compositional gradients, from fire-dependent oak savanna to fire-intolerant mesophytic forests, often ringed Native villages or travel corridors from which broadcast burning emanated (Dorney and Dorney 1989). Even though presettlement trees tended to be large on average (quadratic mean diameter of 30 to 42 centimeters [cm]), stand basal areas were low to moderate, as a result of tree sparseness (9 to 22 square meters [m 2 ] per ha; Fralish et al 1991).…”