Growth Dynamics of Young Mixed Norway Spruce and Birch Stands in Finland

Mixed-species forests in Fennoscandia are of increasing interest because they may improve resilience, biodiversity, and productivity. Currently there is scarce knowledge available the early growth dynamics mixed spruce–birch stands even-aged managed production with artificial regeneration spruce. The main objective our study was to examine present state past current single-storied, young (Picea abies (L.) Karst., Betula pendula Roth, pubescens Ehrh.) (age 17–29 years), where spruce planted birch naturally regenerated, juvenile management practices (early cleaning precommercial thinning) were carried out. We inventoried ten such Southern Finland, for a total twenty plots. For 160 spruces trees, we reconstructed diameter height through stem analysis. analyzed mean stand characteristics by tree species, modelled individual using effects Chapman–Richards model. Spruces had slower initial growth, but age about 20 years their rate eventually approached exceeded that birches regenerated at time planting. even sooner (at 10 years). Thus, not suppressed birches, coexist same canopy layer stands. Contrary earlier guidelines, due fast spruces, mixture needs be maintained already first (i.e., cleaning). young, spruce, allow establishment mixtures also maintenance future until end rotation, thus improving biodiversity boreal, forests.