FACTORS CONTROLLING SPATIAL VARIATION OF TREE SPECIES ABUNDANCE IN A FORESTED LANDSCAPE

Abstract

Spatial patterns of tree species in forested landscapes are regulated by a variety of environmental and disturbance factors. Biological factors such as disturbance and competition that operate within a local neighborhood (neighborhood factors) might also influence these patterns. We sought empirical evidence for the role of neighborhood factors in determining spatial patterns of abundance of dominant tree species in the 3160-ha Hubbard Brook Experimental Forest (HBEF), a second growth, northern hardwood–conifer forest in New Hampshire, USA. We measured tree abundance patterns and a suite of environmental and disturbance factors expected to regulate these patterns in 0.05-ha plots distributed throughout the Hubbard Brook Valley. Environmental and disturbance effects were modeled using linear regression with spatially correlated errors described by semivariograms. These models explained 26–62% of the variation in abundance among the seven tree species that comprise 90% of the total basal area in the HBEF. S...