Spatial patterns of natural Pinus strobus L. regeneration in a Pinus resinosa Ait. stand

Understanding the regeneration niche of white pine (Pinus strobus L.) is necessary to promote the restoration of this formerly widespread species. We tested several hypotheses drawn from the literature relating to four features of the regeneration niche for P. strobus: distance to seed source, overstory influence, segregation into spatial neighborhoods, and deer browsing. All hypotheses were tested in a 0.36-ha stem-mapped Pinus resinosa Ait. stand with abundant naturally regenerating P. strobus. Few regenerating P. strobus were found in the immediate vicinity of the seed source tree or other overstory trees and the distribution of distances away from the seed tree differed for very young (<5 yr) and older regeneration. The spatial arrangement of older regeneration was less associated with the overstory than that of young regeneration, although growth rates were lower in areas of higher overstory influence. Evidence was found for the segregation of regeneration on the basis of size and age classes into spatially distinct neighborhoods, which varied in spatial extent. Spatial segregation was also observed for regeneration that had been browsed, although this was not related to size. Our results supported some hypotheses gleaned from the literature and refuted others, indicating that our understanding of the germination and establishment niches of P. strobus is as yet too immature to predict the factors shaping the regeneration niche.