Compositional, cover, and diversity changes after prescribed fire in a mature eastern white pine forest

Document Type

Article

Publication Date

12-1-2008

Abstract

Eastern white pine (Pinus strobus L.) forests are considered fire dependent, but little is known about the role of low-intensity fires. We conducted four prescribed burns to examine understory effects. The vegetation was sampled one year before and two consecutive years after the burns. Understory metrics were calculated for the vernal (May-June) and aestival (mid-August) assemblages. The fires resulted in a cumulative mortality rate in the sapling layer of 64%. During the first year, the burns had a neutral or repressive effect on the understory. However, cover, richness, and species density increased significantly for both assemblages during the second year; however, the relative change was greater for the vernal assemblage. The fires also led to greater compositional turnover than in the controls. The large increases in late-season cover were primarily from reduced competition and enhanced regeneration. The fires created a brief window of invasion opportunity, which was minimally captured by annuals and exotics. Ordination indicated different short-term successional pathways for the vernal (diverging) and aestival (converging) assemblages. This difference by time period was consistent with similarity measures. The study suggests that low intensity fires play a vital role in understory diversity and structure in white pine forests. © 2008 NRC.

Publication Title

Botany

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