Goal: Apply Knowledge Globally How do insects, diseases, and weather disturbances interact? An assessment of current knowledge for the South

Forests in the southern U.S. experience a wide variety of weather-related disturbances, from fine-scale events with management implications for one or a few landowners to major hurricanes that impact many ownerships across multiple states. The immediate impacts of catastrophic weather disturbance are obvious—trees are killed, stressed, or damaged due to wind, flooding, ice, hail, or some combination of events. How forests respond to disturbance depends on several factors, including forest types and attributes, ecoregion, local pressure from invasive plants, preexisting infestations of pests and pathogens, prior disturbance events, and other variables which interact in complex ways, influencing successional dynamics and management decisions.

Researchers synthesized the major weather perturbations affecting the forests of the southern U.S. and current state of the knowledge surrounding interactions between these events, forest pests, and forest diseases in a new publication. The research compiles non-quantitative observations between 1955 and 2018 from annual USDA Forest Service “Major Forest Insect and Disease Conditions in the United States” reports that describe where insects or diseases were found on trees that were stressed by weather disturbances.

The research presents two conceptual models, one describing changes in forest structure and composition and another that outlines herbivorous pest population fluctuations following different severity levels of disturbance. Finally, the study proposes eleven questions that require additional research to better inform sustainable forest management decisions in preparation for and in response to catastrophic weather events.