Climate-Sensitive Growth and Yield Models and Their Application to Assisted Migration

Abstract

Abstract Growth and yield (G&Y) of forest plantations can be significantly impacted by maladaptation resulting from climate change, and assisted migration has been proposed to mitigate these impacts by restoring populations to their historic climates. However, currently used genecology models for guiding assisted migration lack accounting for impacts of climate change on cumulative growth and requires assumption that responses of forest population to climate do not change with age. Using provenance trial data for interior lodgepole pine (Pinus contorta subsp. latifolia Douglas) and white spruce (Picea glauca (Moench) Voss) in western Canada, we integrated Universal Response Functions (URFs), representing the relationship of population performance with their provenance and site climates, into a G&Y model (Growth and Yield Projection System, GYPSY), to develop a climate-sensitive G&Y model for both species, and therefore to estimate climate change’s impacts on G&Y of local and moving populations and guiding assisted migration. Our findings reveal that climate change is expected to have varying effects on forest productivity across the landscape, with partial areas projected to experience a slight increase in productivity by the 2050s, while rest areas projected to face a significant decline in productivity for both species. Adoption of assisted migration with optimal populations selected was projected to maintain and even improve its productivity at the provincial scale. The findings of this study highlight the importance of accounting for climate change in forest management practices and underscores the relevance and benefits of incorporating assisted migration approaches to mitigate the negative impacts of climate change.