Monitoring Forest Drought and Vegetation Responses Using Remote Sensing: A Systematic Review of Open-Access Literature

Drought is an increasingly important driver of forest stress, decline, and mortality worldwide. Remote sensing has become an essential tool for monitoring these processes from local to global scales. This article presents a systematic review of open-access studies published between 2020 and 2026 that employed remote sensing techniques to monitor drought-related vegetation conditions and responses in forest ecosystems, with particular emphasis on studies employing vegetation indicators such as NDVI, EVI, and LAI. The review further examines the sensors, platforms, environmental variables, and complementary remote sensing approaches integrated with these indicators to characterize forest responses to drought. Attention is given to how these integrated approaches combine diverse environmental and ecological variables, advancing remote sensing from the detection of vegetation change to a more comprehensive assessment of forest vegetation responses to drought. Following PRISMA guidelines, 68 open-access studies were systematically identified and selected, and a qualitative content analysis using MAXQDA was conducted to identify and quantify the most frequently reported research trends, limitations, key findings, and future directions across the selected studies. By synthesizing recent developments in multiscale and multisource remote sensing, this review highlights emerging and existing approaches for characterizing drought-related forest vegetation responses, identifies persistent methodological and observational challenges, and outlines priorities for advancing more integrated and robust forest drought monitoring.