Forest Observation for Drought Legacy Effects, Natural Resource Management, and Stewardship (Forest-LENS)

Climate projections for Central Europe indicate a continued rise in the frequency and severity of extreme drought events. This will place increasing pressure on the productivity and biodiversity of temperate forests. Thinning, which promotes growing space for trees, is a primary drought mitigation strategy for forest stands, but its long-term effectiveness is dependent on site- and stand-specific conditions that have yet to be fully characterized.

The Forest-LENS project aims to expand satellite remote sensing approaches to detect both management related thinning and drought legacy effects, evidence of long-term tree decline like crown dieback or mortality resulting from drought. This detection will allow us to examine the multi-annual trajectory of drought damage under a range of forest conditions and the effectiveness of thinning in mitigating drought impacts. The project builds on the DRAINS project (2023 to 2026) which used high-resolution Sentinel-2 imagery to distinguish early leaf discoloration from legacy effects of drought in European beech (Fagus sylvatica). Early leaf discoloration is a seasonal signal of drought stress and a precursor to legacy effects.

In collaboration with forest managers, Forest-LENS will 1) aggregate and supplement forest management records for beech dominated forests; 2) train machine learning models on drought legacy effects and forest management using remote sensing time series; 3) apply and validate these models to classify drought legacy effects and forest management; and 4) evaluate the effectiveness of thinning in enhancing or hindering drought resilience under a range of site conditions.