Successful hard pine regeneration and survival through repeated burning: An applied historical ecology approach

摘要

Forest inventories commonly report fire-adapted pine populations severely reduced from pre-EuroAmerican times due to the combined effects of past land uses and altered fire regimes. Relatively little information exists about the fire ecology and management of hard pine ecosystems in the northeastern U.S. The objective of this study was to determine what burning frequencies best promote regeneration and recruitment of three hard pine species native to the northeastern U.S. We used data from dendrochronological fire history studies to derive historical fire years, pine regeneration years, and individual tree survival information. For all tree species, pith calendar years ranged from 1530 to 1932 with the majority of regeneration occurring prior to 1754 (the earliest dates of EuroAmerican settlement). The number of years from fire occurrence at a site to regeneration (pith year) ranged from 0 (i.e., regeneration occurred in year of fire, n = 9) to 130 with a median of 8 years. Frequency distributions of regeneration following fire were similarly shaped across species, all being strongly negatively skewed (i.e., most regeneration occurred soon after fires) and increasing abruptly (> 100% increase) from 0 to 1 year since fire and then declining following a negative exponential curve. The number of years from regeneration to the next fire ranged from 0 to 172 years with a median of 14 years. Frequency distributions of hard pine survival were negatively skewed, with the exception of red pine. Overall, these data suggest that these species exhibit relatively high regeneration in the years immediately following fire events and a subsequent decrease with time since fire. Although other factors may affect the regeneration of pine following fire, it appears that significant statistical relationships can be established and used to develop effective fire frequency guidelines for successful hard pine regeneration.