Thermal differences between juveniles and adults increased over time in European forest trees

Woody species’ requirements and environmental sensitivity change from seedlings to adults, a process referred to as ontogenetic shift. Such shifts can be increased by climate change. To assess the changes in the difference of temperature experienced by seedlings and adults in the context of climate change, it is essential to have reliable climatic data over long periods that capture the thermal conditions experienced by the individuals throughout their life cycle. Here we used a unique cross-European database of 2195 pairs of resurveyed forest plots with a mean intercensus time interval of 37 years. We inferred macroclimatic temperature (free-air conditions above tree canopies – representative of the conditions experienced by adult trees) and microclimatic temperature (representative of the juvenile stage at the forest floor, inferred from the relationship between canopy cover, distance to the coast, and below-canopy temperature) at both surveys. We then address the long-term, large...