Long-term drought sensitivity of trees in second-growth forests in a humid region

Abstract

Classical field methods of reconstructing drought using tree rings in humid, temperate regions typically target old trees from drought-prone sites. This approach limits investigators to a handful of species and excludes large amounts of data that might be useful, especially for coverage gaps in large-scale networks. By sampling in more “typical” forests, network density and species diversity would increase in ways that could potentially improve reconstructions. Ten nonclassical tree-ring chronologies derived from randomly selected trees, trees from logged forests, or both were compared to more classical chronologies and an independent regional drought reconstruction to determine their usefulness for dendrohydroclimatic research. We find that nonclassical chronologies are significantly correlated to classical chronologies and reconstructed drought over the last 2–3 centuries. While nonclassical chronologies have spectral properties similar to those from classical dendroclimatic collections, they do lack spectral power at lower frequencies that are present in the drought reconstruction. Importantly, our results show that tree growth is strongly dependent on moisture availability, even for small, randomly selected trees in cut forests. These results indicate that there could be more data available in areas with few current tree-ring collections for studying climate history and that drought plays an important role in humid forests.

The impacts of increasing drought on forest dynamics, structure, and biodiversity in the United States

“…Despite differences in collections and land‐use histories, they show a similar change in direction during specific PDSI conditions, positive growth during wet conditions ( PDSI ≥ 2) and vice versa (adapted from Pederson et al . (,b).…”

Land snail diversity can reflect degrees of anthropogenic disturbance

“…Both FSNP study forests were likely selectively logged at the beginning of the 1900s. However, age structure of the younger forest (Pederson et al 2012) and current physical structure indicates that it experienced great disturbance severity. Of the five trees cored in the younger forest, the average age was 146.8 years, while the average age in the older section among the 15 cored trees was 295.0 years (Pederson et al 2012).…”

“…However, age structure of the younger forest (Pederson et al 2012) and current physical structure indicates that it experienced great disturbance severity. Of the five trees cored in the younger forest, the average age was 146.8 years, while the average age in the older section among the 15 cored trees was 295.0 years (Pederson et al 2012). Our findings suggest that land snails may be extirpated from forests that are managed through intensive forestry (i.e., clear-cutting) at large scales.…”

“…Much of the preserve was logged around the beginning of the 1990s and later used for agriculture. Despite these disturbances, sampling was conducted in an area containing numerous trees 200-400 years old and a second area with trees that are ,125 years old (Pederson et al 2012). Within the Appalachian Plateau ecoregion we sampled in Big Everidge Hollow, an old-growth forest that contains trees 300þ year old trees, at Lilley Cornett Woods Appalachian Ecological Research Station (LCW) and at Pole Branch, a secondgrowth forest paralleling Big Everidge Hollow that was clear-cut in 1945 and then contourmined in 1970 (Muller 1982).…”

“…Within the Appalachian Plateau ecoregion we sampled in Big Everidge Hollow, an old-growth forest that contains trees 300þ year old trees, at Lilley Cornett Woods Appalachian Ecological Research Station (LCW) and at Pole Branch, a secondgrowth forest paralleling Big Everidge Hollow that was clear-cut in 1945 and then contourmined in 1970 (Muller 1982). On the Cumberland Mountain Thrust Block ecoregion we sampled at Blanton Forest State Nature Preserve (BFSNP), an old-growth forest containing three tree species 324-337 years old (Pederson et al 2012), and at Kentenia State Forest (KSF), a second-growth forest that has experienced both fire and logging events. Detailed accounts of disturbance histories for KSF are not available.…”