Prescribed fire promotes regeneration in a mature eastern white pine forest

Abstract

Although evidence indicates that fire exclusion may result in substantial short- and long-term changes to forest stand structure and composition, the long-term effects on eastern white pine (Pinus strobus L.) stands remain largely unknown. We investigated the response of trees and understory vegetation after prescribed burning in a mature white pine stand in northern Ontario, Canada. Results indicate that a single prescribed burning treatment improved regeneration of white pine and other mid-shade tolerant species compared to controls whereas repeated burning favoured shade intolerant species such as trembling aspen (Populus tremuloides Michx.). Unburned control plots had a substantial understory component of shade tolerant balsam fir (Abies balsamea [L.] Mill.). We simulated stand compositions after 70 years post-treatment and found that prescribed burn plots had much higher volume of white pine compared to unburned plots. Overall, the results highlight fire severity as a driving influence on the successional trajectory of white pine stands. The findings support low to moderate prescribed burning of mature white pine-dominated forests as an effective means to retain a white pine component within areas of the Great Lakes-St. Lawrence forest region.