Wood Production Efficiency and Growth Dominance in Multiaged and Even-Aged Ponderosa Pine Stands

Twenty-first century forests are managed for myriad benefits including esthetics, habitat, and other ecosystem services. Multiple management objectives can often be accommodated by multiaged stand structures. Consequently, multiaged silviculture is increasingly considered in place of even-aged methods. When multiaged methods are adopted in commercial forestry settings, it is important to consider potential impacts to wood production. Evaluating wood production efficiency (usually expressed as periodic annual increment per unit leaf area) of different sized trees in multiaged stands helps illuminate the effects of stand structure on productivity. Growth dominance analysis is an alternative method that compares proportion of stand biomass or volume carried by trees with the proportion they produce. We analyzed production efficiency patterns in multiaged ponderosa pine stands and compared results to trends in growth dominance. Small trees in multiaged stands were ~20% less efficient than large trees, yet we found no overall difference between multiaged and even-aged structures. Surprisingly, dominance analysis implied that small trees were more productive than medium or large trees in multiaged stands. However, when dominance analysis was repeated using leaf area instead of stem volume as a metric of resource acquisition, this trend disappeared. Results indicated that multiaged prescriptions for wood production should consider production efficiency differences between size classes of trees and that growth dominance curves created using leaf area illustrate tree size-productivity trends in multiaged stands. [PUBLICATION ABSTRACT]