Abstract
Insects and diseases are significant disturbance agents in many forests. In some places, annual surveys by observers in aircraft are valuable resources but can have significant issues that result in gaps. Using remotely sensed data is therefore attractive. Here we provide a review of this topic that is novel in several ways. We describe tree, stand, and landscape responses to insects and diseases, then link these responses to remote sensing technologies and methods for detection and attribution. We focus on insects and diseases that cause substantial damage and mortality to conifers in the western United States (excluding Alaska and Hawaii) but present information in a general way that allows for extension to other regions. Tree responses (e.g., color change) can vary but can be generalized within groups of host tree/disturbance agent associations. At stand and landscape levels, spatial and temporal characteristics of tree damage or mortality can differ substantially within and among agents. A variety of remote sensing technologies and methods are available for exploiting the host tree responses to detect and attribute damage and mortality. Important knowledge gaps exist that limit detection and monitoring, but recent rapid developments in technologies and methods show significant promise. Our review provides scientists and managers with information for advancing remote sensing capabilities related to forest insects and diseases.