Effects of stand density on ecosystem properties of subalpine forests in the southern Rocky Mountains, USA

• Mixed coniferous, subalpine forest communities in the Rocky Mountains are historically dense and have experienced infrequent, high-severity fire. However, many of these high-elevation stands are thinned for a number of perceived benefits. • We explored the effects of forest stand density on ecosystem properties in subalpine forests in Colorado, USA, 17–18 y after forests were managed for timber. • Forest structure significantly altered the composition and chemical signature of plant communities. Previously managed stands contained lower density of overstory trees and higher ground cover compared to paired reference stands. Foliar phenolic concentration of several species was negatively related to basal area of overstory trees. Furthermore, reductions in stand density increased total foliar phenolic:nitrogen ratios in some species, suggesting that gap formation may drive long-term changes in litter quality. Despite significant changes in forest structure, reductions in stand density did not leave a strong legacy in surface soil properties, likely due to the integrity of soil organic matter reserves. • Changes in forest structure associated with past management has left a long-term impact on plant communities but has only subtly altered soil nutrient cycling, possibly due to trade offs between litter decomposability and microclimate associated with reductions in canopy cover.