Remote Sensing of Vegetation Dynamics
Authors: Hill Michael J. 
Published: January 2025

Vegetation dynamics is the term applied to changes that occur in the spatial distribution, seasonality, horizontal extent, vertical structure and composition, and temporal trends and variations associated with growth, senescence, dormancy, death, and regeneration. For this article, it excludes land clearing detection and agricultural rotations. It operates across a wide range of spatial and temporal scales from instantaneous biochemical processes to biome-scale shifts that occur over decades to millennia. Satellite remote sensing has been an indispensable tool in the monitoring of these changes since the late twentieth century. Prior to the advent of satellites, airborne photography, and historical ground-based photographic comparisons were used to identify changes. However, these usually only provided snapshots in time with no record of the process of change observed in the comparison. The launch of polar orbiting satellites carrying the National Oceanic and Atmospheric Administration’s Advanced Very High-Resolution Radiometer (NOAA AVHRR) with daily repeat overpasses provided the means for capturing, for the first time, the behavior of global vegetation across the seasons and years. The spectral bands on AVHRR included a red visible band and a near-infrared (NIR) band. The normalized ratio of reflectance between these bands, the Normalized Difference Vegetation Index (NDVI), provided a robustly sensitive indicator of photosynthetic capacity—a measure of vegetation greenness. The seminal scientific studies using NDVI images from AVHRR over the Sahel and southern Africa published in the early 1980s ushered in the modern era of global monitoring of vegetation dynamics with satellite remote sensing. Since that time, remote sensing of vegetation dynamics and change has become the standard approach to monitoring from plot, paddock, and farm to landscape, region, country, and across the globe. The suite of remote sensing types, sensor configurations, and products has expanded greatly to include radar polarimetry and interferometry, LiDAR (light detection and ranging) detection of three-dimensional vegetation structure, imaging spectroscopy for detection of vegetation biochemistry (measuring absorption and reflectance within hundreds of narrow spectral bands), very high resolution imaging down to centimeter pixels from hundreds of small satellites, thermal remote sensing of vegetation, and highly sophisticated products measuring evapotranspiration, net primary productivity (NPP), leaf area index (LAI), fraction of absorbed photosynthetically active radiation (fAPAR) etc. at 500–1000 m resolution with more than twenty years of global daily imaging. The spatial and temporal fidelity at global scale has now been enhanced by having multiple multispectral sensors from NASA (National Aeronautics and Space Administration) and ESA (European Space Agency) with 10–30 m pixel resolution and compatible spectral characteristics in orbit at the same time. This topic has seen exponential growth in publications over the past decade with more than twenty-thousand entries found in searches with Scopus or Web of Science. This article provides an introduction to this vast array of publications addressing vegetation dynamics and dynamic change.