Application of Remote Sensing Technologies for Assessing Planted Forests Damaged by Insect Pests and Fungal Pathogens: a Review

Purpose of Review In this review, we highlight recent developments and applications in remote sensing that can improve the accuracy and timeliness of health assessments in plantations managed for timber and pulp production. The detection and mapping of damage extent and severity caused by insect pests and fungal pathogens is a common requirement of foresters managing plantations. The objectives of these surveys can range from early detection for targeted intervention to more strategic aims of predicting stand susceptibility or evaluating the performance of management strategies. Recent Findings Recent developments in remote sensing technologies and big data modelling techniques can now provide spatially explicit, quantitative solutions for these management objectives that are more accurate than manual field-based assessments of tree damage or airborne visual mapping. Past studies have identified a large number of spectral, textural and structural metrics that have been used in models to classify specific tree crown damage symptoms. This process requires a detailed understanding of the chronology of crown symptoms for specific damaging agents and the spectral responses to these symptoms. Continuing increases in the spatial and spectral resolution of remote sensors enables crown-level damage classification. Summary The development of data processing workflows that fuse spectral information with three-dimensional (3D) data acquired simultaneously from single or different remote platforms promote the opportunities to derive both structural and physiological crown-level attributes that relate to crown damage. The simultaneous acquisition of spectral and 3D point data will enable plantation foresters to derive several spatial products, including the assessment of tree health in a cost-effective manner.