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Decreasing water availability reduces productivity in Swiss forests along an altitudinal gradient

A 30-year study of 18 Swiss forest sites revealed a decline in forest productivity, especially since 2015, across all altitudes, age classes, and tree species. This decrease cannot be explained solely by forest ageing or stand density, but is also linked to reduced soil water availability and nitrogen deposition. Tree growth and regeneration rates were […]

A 30-year study of 18 Swiss forest sites revealed a decline in forest productivity, especially since 2015, across all altitudes, age classes, and tree species. This decrease cannot be explained solely by forest ageing or stand density, but is also linked to reduced soil water availability and nitrogen deposition. Tree growth and regeneration rates were identified as the main drivers of productivity decline. Even at similar stand densities, forests in recent years showed lower productivity than in previous decades. The findings suggest a reduced long-term growth capacity of forests and highlight the crucial role of water availability under increasing drought and heat conditions caused by climate change.

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