An Evaluation of the Main Factors Affecting Yield Differences between Single- and Mixed-species Stands

In British Columbia, many of our second-growth stands have regenerated as mixed-species stands and yet our understanding of how to manage these stands to achieve multiple goals is limited. There is considerable interest and need to identify management strategies that will optimize timber production and carbon storage while maintaining biodiversity in the province’s managed forests. Careful use of mixed-species management may contribute to meeting these goals. This discussion paper reviews the published literature that compares yield in single-and mixed-species stands. The review shows that drawing any definitive con- clusions on whether mixed-species stands had a higher yield than single-species stands is not possible because of the confounding influence of four key factors: 1) species composition; 2) site type; 3) density and pattern; and 4) assessment age. To plan mixed-species plantations with native species that may out-yield monocultures and have other potential benefits, silvi- culturists will need to extrapolate from past research and pay close attention to these factors.