Calcium addition modulates water use strategy of tree species with contrasting Al-tolerance in South China secondary forest.

Calcium addition shifts water use strategies in Al-tolerant tree species, with Al-excluders becoming more acquisitive and Al-accumulators adopting conservative traits.

• Why it matters: Understanding how soil amendments influence plant water use is crucial for managing forests affected by acid deposition and aluminum toxicity, which threaten ecosystem health.
• What they did: The study involved a field experiment with simulated acid deposition and calcium addition in a South China secondary forest, measuring leaf traits, water use efficiency, and stomatal features across four tree species with contrasting Al tolerance.
• The result: Calcium availability primarily drives leaf functional adjustments, enabling Al-excluders to shift toward resource acquisition and Al-accumulators to enhance water use efficiency, informing forest management strategies under changing soil chemistry.