Solar Radiation and Water Stress Are Major Environmental Drivers of the Latitudinal Pattern of Leaf Si Concentration in Woody Plants

ABSTRACT Aim Silicon (Si) enhances plants' resistance to environmental stress. Forests absorb much more Si than other vegetation types, making it crucial to comprehend the factors influencing Si concentration in woody plants for studying global terrestrial Si cycling, especially under significant environmental changes. Here, we analyze the latitudinal pattern of leaf Si concentration in woody plants and identify its main environmental drivers. Location Worldwide; covering six continents except Antarctica. Time Period 1945–2023. Major Taxa Studied Terrestrial woody plants. Methods We compiled a dataset of leaf Si concentration for wild terrestrial woody plants and analysed the latitudinal patterns of leaf Si concentration and their environmental drivers. Results We revealed a significant unimodal latitudinal pattern of leaf Si concentration in woody plants, peaking in subtropical high‐pressure regions. Solar radiation and water stress are the main environmental drivers of this pattern. Additionally, different plant functional groups with distinct concentrations but similar latitudinal trends of leaf Si, together with their latitudinal distribution shifts, intensify this pattern. Main Conclusions High leaf Si concentration is an important adaptive strategy for woody plants to mitigate the adverse effects of intense solar radiation and water stress in subtropical high‐pressure regions. The biogeography of leaf Si in woody plants revealed here provides insight into the macro‐evolution of Si in plant stress resistance and highlights its important role in sustaining forest productivity under global climate change.