Tree Line Change Detection Using Historical Hexagon Mapping Camera Imagery and Google Earth Data

Abstract

Monitoring the response of tree lines to climatic change requires long time series. Therefore ground-based studies, initially designed for other purposes, are used, causing a bias in the sampling design. Using historical satellite data might overcome this bias. This study explores the usability of historical spy-satellite imagery from the United States Hexagon missions to detect changes in tree lines. We find that both vertical and horizontal errors are within acceptable boundaries (± 18.0 m in horizontal direction and 5.5 m in vertical direction) to detect change. This opens opportunities to explore tree line changes globally with a more robust sampling strategy.