The most warming-prone regions of the United States have experienced the heaviest forest pest damage over the past two decades, with maximum summer temperature emerging as the single most consistent climate signal across damage data for 30 high-impact insect species. That is according to lead author Hannah L. Clipp, a researcher with the USDA Forest Service Northern Research Station, whose findings were published earlier this month in Nature Ecology & Evolution.
Wood Central understands that the study, co-authored with USDA Forest Service Southern Research Station researcher Kevin M. Potter and Northern Research Station scientists Matthew P. Peters, Anantha M. Prasad, Stephen N. Matthews, and corresponding author Andrew V. Gougherty, drew on 20 years of US Department of Agriculture Insect and Disease Survey records spanning the conterminous United States from 2000 to 2019.
The Clipp-Gougherty team analysed forest damage caused by 30 focal pest species, including emerald ash borer, mountain pine beetle, southern pine beetle, hemlock woolly adelgid, and spruce budworm, against five bioclimatic variables, finding that maximum temperature in the warmest month and the rate of warming relative to a historical baseline both produced consistent damage signals across the dataset.
The mean damage from the focal species was higher in regions with moderate maximum temperatures and in regions where warming had accelerated, with the direction and magnitude of those relationships shifting between pest guilds and across native and non-native species, the authors found.
The paper differentiated between bark-beetle and defoliator species and found that climate-damage relationships also varied between western and eastern regions of the conterminous United States across the 30-species dataset.
Within the methodology, the Clipp-Gougherty team distinguished between current climate conditions and the climate anomaly, or the deviation from a historical baseline, finding that, for several focal species, the rate of warming, rather than absolute temperature, carried the stronger damage signal.
Wood Central understands the emerald ash borer, first detected in Michigan in the 1990s and 2000s and now established across the eastern United States, was among the species for which warming winters in the Great Lakes region, its presumed point of introduction, appear to have lifted overwinter survival and accelerated spread.
The Insect and Disease Survey data on which the analysis was built are USDA Forest Service aerial-detection records covering insect and disease activity across the conterminous United States, with damage polygons coded by pest species and surveyed each year over the 2000-to-2019 window. The team tested against temperature, precipitation, and historical-anomaly variables.
Two related climate-disturbance studies published in the past four months extend the reach of the Clipp paper, including a January 2026 Nature Plants paper documenting a pervasive increase in tree mortality across the Australian continent, and a September 2025 Nature Climate Change study documenting the rising cost of climate-driven disturbance for European forestry.
Clipp and Gougherty wrote that their findings provided “empirical support for expectations of climate-induced stress to host trees and temperature-boosted pest performance,” with future damage projected to increase as the warmest-month maximum temperatures continue to rise.
Damage from the 30 focal species ran heaviest in the fastest-warming regions of the conterminous United States — with the Clipp-Gougherty paper concluding that climate change had already exacerbated pest performance across two decades of USDA forest-survey records, before the next 20 years of warming the team’s models project will compound the pattern further.
