With increasing site quality asymmetric competition and mortality reduces Scots pine (Pinus sylvestris L.) stand structuring across Europe

Heterogeneity of structure can increase mechanical stability, stress resistance and resilience, biodiversity many other functions services forest stands. That is why silvicultural measures aim at enhancing structural diversity. However, the effectiveness potential structuring may depend on site conditions. Here, we revealed how stand determined by quality results from site-dependent partitioning growth mortality among trees. We based our study 90 mature, even-aged, fully stocked monocultures Scots pine (Pinus sylvestris L.) sampled in 21 countries along a productivity gradient across Europe. A mini-simulation further analyzed site-dependency interplay between resulting structure. The overarching hypothesis was that changes with asymmetry competition mortality. First, show stands Europe become more homogeneous increasing quality. coefficient variation Gini stem diameter tree height continuously decreased, whereas Stand Density Index basal area increased index. Second, reveal distribution trees With index, both suggested, first glance, an heterogeneity. eliminates mainly small instead all-sized trees, cancels size reduces Third, modelled By scenario runs for different conditions, level emerges asymmetric Our most interesting finding became quality, but eliminated predominantly reduced their thus reversed impact Finally, reverse effects mode resulted highest poor sites decreased heterogeneity Since indicate where heterogeneous structures need silviculture interventions they emerge naturally, conclude these findings improve system understanding modelling guide management aiming structurally rich forests.