Silicon Cycling in Forest Ecosystems: A Review Focusing on the Role of Soil Biogeochemistry

Silicon (Si) affects soil formation, carbon (C) cycling, nutrient dynamics, vegetation growth and plant stress resilience, all of which are critical to the general health and sustainability of forest ecosystems. Despite its abundance and diverse functions, the pivotal role of Si in forest ecology is frequently overlooked. This review aims to clarify the intricate role of Si in forest ecosystems by focusing on soil genesis and properties, vegetation requirements, and biogeochemical cycles. Podzolization and laterization, two distinct pedogenic processes with differing Si chemistries, are strongly influenced by forest vegetation type. Si is the basic building block of sand, silt, and clay, and influences soil properties such as soil erodibility, long-term nutrient availability, and water retention, which are fundamental for sustainable forest management. In addition to providing mechanical support, Si protects several plant species from both biotic and abiotic stresses, thereby enhancing forest longevity and health. Soil-plant Si dynamics influence C sinks by stabilizing phytoliths, accelerating silicate weathering, and prolonging biomass lifespan. The stability of phytoliths and silicate minerals in the soil is governed by interactions among Si pools, fluxes and biogeochemical cycles. Forest vegetation composition, stand maturity, and Si absorption capacity also play significant roles. Therefore, research on Si in forest ecosystems is crucial for ecological science and sustainable forest resource management. This is particularly important in addressing current global environmental challenges, where Si’s influence on soil stability, nutrient cycling, and C sequestration has far-reaching implications.