Tree species mixing can amplify microclimate offsets in young forest plantations

Macroclimate warming is affecting ecosystems world-wide. Tree canopies, however, can significantly buffer temperature fluctuations, giving rise to lower maximum temperatures, higher minimum temperatures and enhanced water availability at the forest floor. Forests, therefore, act as refugia for heat-sensitive species with important implications climate-change responses in understorey of forests. These microclimate offsets have been well-studied, but far less known about how are modulated by tree mixing. We installed air humidity loggers a multisite diversity experiment quantify role richness composition on below-canopy investigate mechanisms underlying these effects. Microclimate highly depended identity Not only monocultures larch Larix × eurolepis Douglas fir Pseudotsuga menziesii had high performance thermal buffering, also mixtures such birch Betula pendula pine Pinus sylvestris. Indirect effects brought mixing were found amplify offsets, mostly via increased canopy cover. Synthesis applications. Our findings show that offsetting depends diversity, buffered microclimates be achieved rapidly young plantations, depending being planted. Based our findings, we recommend planting instead monocultures. because was some investigated stands, likely increase resilience forests climate change. Hence, expect long-term might beneficial buffering. Forest managers policy makers use finding optimise design plantations minimise impacts biodiversity functioning.