Abstract
Abstract
Wild berries are economically and socially important non-timber forest products in northern and eastern Europe, yet effects of silvicultural treatment intensity on their production remain understudied outside the Nordic countries. Using a replicated Before-After-Control-Impact design in 20 Scots pine (Pinus sylvestris L.) stands in Latvia, hemiboreal zone, we compared soil chemistry and bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.) cover, height and yield across two thinning intensities (residual relative density 0.68 and 0.38) and an unthinned control over four years post-thinning. Thinning intensity was not associated with post-thinning soil chemistry. Lingonberry showed clear, statistically robust responses to thinning in cover, yield, and the yield-cover relationship, with cover diverging among density classes from the third study year onward, whereas bilberry showed no significant response in any trait, despite point estimates trending in the same direction. Redundancy analysis showed that stand structure and soil chemistry jointly explained a similar proportion of variance in both species, but this association held under a nested plot-within-site design only for lingonberry. Moderate thinning can therefore enhance lingonberry production within a few years without measurably altering soil chemistry. Where both species matter for non-timber forest product provision, they require distinct silvicultural consideration.