Mixing effects on Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) productivity along a climatic gradient across Europe

Mixed-species stands have been found to be more productive than would expected from the performance of their component species in monocultures due facilitation and complementarity between species, although these interactions depend on combination present. Our study focuses monospecific mixed-species Scots pine Norway spruce using 20 triplets established nine countries along a climatic gradient across Europe. Differences mean tree stand characteristics, productivity structure were assessed. Basal area increment mixed was 8% higher while volume only 2% greater. trees growing showed 11% larger quadratic diameter, 7% dominant 17% basal 25% stands. non-significant tendency lower values diameters, heights, area, as well standing mixtures monocultures. Stand indices differed showing greater stratification Furthermore, studied morphological traits little variability for stands, except diameter at breast height, crown length ratio. For all identified different. Some associated with relative productivity. Nevertheless, not related site conditions.