The effects of intensive eradication efforts for Asian longhorned beetle on understory plant communities, tree regeneration, and forest structure in southern New England hardwood forests

Abstract

The United States has been experiencing an influx of nonnative pests due to increased globalization, and these pests have the potential to permanently alter the composition, structure, and function of forests. Asian longhorned beetle (ALB) is an invasive pest detected in Worcester, MA in 2008, where it invaded both urban and natural forested areas. As a part of the eradication measures (full host removals, herbicide treatments, and stump grinding), all host tree species, primarily Acer spp. were removed to prevent the spread of ALB. While these eradication measures successfully eliminate ALB, little is known about their effects on forest structural and compositional conditions and recovery over time. To address this, we examined forest compositional and structural development following eradication treatments and in adjacent unimpacted forested areas. Overall, our results indicated forest recovery followed similar pathways documented after natural disturbances in southern New England forests. There was little difference among eradication treatments in terms of the resultant forest composition and structure. Overall, forest types shifted to primarily oak-hickory or pine dominance following the removal of all Acer spp. Notably, maple species were present in high numbers in the regeneration layer regardless of treatment, followed by other early colonizing species. Red maple (Acer rubrum) was the most abundant sapling and seedling species and stump sprouting occurred at 60% of sites but was absent in untreated areas. These results suggest that ALB management does not drastically alter forest compositional dynamics in these mixed species forests in the short term, despite significant reductions in the abundance of mature host species through eradication treatments.