Interactions Between Weather-Related Disturbance and Forest Insects and Diseases in the Southern United States

Abstract

Forests in the Southern United States experience a wide variety of weather-related disturbances, from small-scale events which have management implications for one or a few landowners to major hurricanes impacting 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 such as 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. In this review, we synthesize the major weather perturbations affecting the forests of the Southern United States and current state of the knowledge surrounding interactions between these events, forest pests, and forest diseases. We present a compilation of non-quantitative observations between 1955 and 2018 from annual U.S. Department of Agriculture Forest Service “Major Forest Insect and Disease Conditions in the United States” reports describing where insects or diseases were found on trees that were stressed by weather disturbances. Two conceptual models are presented, one describing changes in forest structure and composition, and a generalized model of herbivorous pest population fluctuations following different severity levels of disturbance. Finally, we propose 11 questions that require additional research to better inform sustainable forest management decisions in preparation for and in response to catastrophic weather events.