Thin forest stands

Stand thinning is one of the oldest tools in the forester's kit. By removing a fraction of the trees in a dense stand, the remaining trees face less competition for soil water, light, and nutrients. During moderate droughts, thinned stands have measurably lower mortality and recover faster than unthinned ones — a result confirmed across decades of European and North American forestry research. The limit of the technique is severity. When drought is mild to moderate, thinning helps. When drought is extreme — multi-year, with high temperatures and depleted soil moisture — even widely spaced trees run out of water and die. Thinning cannot save a forest from collapse; it can only extend the runway and reduce the rate of damage. In the Grand Est, ONF foresters apply thinning as a standard response in communal and state forests, including in stands that have already started to decline. The results are visible: thinned spruce and beech stands fare better through dry summers than dense ones. But foresters also acknowledge openly that thinning alone is insufficient — they have described feeling powerless against droughts that exceed any historical precedent.