Bigtooth aspen trees are very susceptible to fire, although bigtooth aspen roots are very fire resistant. Since most fires in aspen are of low severity, mature trees do not always succumb to fire. Roots must have a high cytokinin to auxin ratio to initiate sucker growth. If a low-intensity fire girdles aspen such that the downward movement of auxin in the phloem is interrupted but the upward movement of cytokinin continues in the xylem, the tree may survive for several years. The density and growth of suckers is dependent in part on fire severity.
Fire also prepares a favorable seedbed for bigtooth aspen.
A mature aspen stand that is clearcut will generally have enough slash for fire to kill any residual standing trees. Three years after treatment, the preflush cut had the greatest stem density, average height, and basal diameter. Both cut treatments had greater stem densities than the burn treatments. The preflush cut treatment probably had more stems than the postflush cut treatment because carbohydrate root reserves were not depleted. One reason for low rates of suckering after prescribed burning was that the fires did not completely kill the overstory.