Beyond greening and browning in northern peatlands: the roles of warming, precipitation, lake drainage, and tree cover

We conducted, to our knowledge, the first multi-decadal, peatland-specific assessment of canopy greening and browning trends across northern peatlands using a gap-filled, sensor-independent climate data record of leaf area index (LAI) for 2001–2023.  We hypothesise that northern peatlands exhibit spatially coherent greening or browning trends in LAI and that these trends can be explained by (i) climate-related changes, including warming, precipitation and recent lake drainage in the northern permafrost zone; (ii) differences in protection status; and (iii) variation in tree cover type and density. We found that although greening was widespread (77% of peatlands; greening-to-browning ratio 3.5:1), there was no statistical evidence for an area-weighted LAI trend at the map scale. Overall, peatland canopy change was not a uniform increase in greenness; rather, LAI responses were moisture-sensitive and dependent on tree-cover context and were further modulated by decadal climate variability.