Assessment of Off-Site Tree Plantations in the Northwest Interior of British Columbia

ABSTRACT The report addresses the impact of climate change on British Columbia's reforestation program. The assumption that the climate and environment are stable, ensuring the suitability of previously harvested tree species for reforestation, is now in doubt due to the rapidly changing climate. Plantation failures in B.C. have increased due to unusual climatic conditions and shifts in forest diseases and insect populations. To ensure sustainable forest resources and related industries, the study focuses on evaluating both the continued suitability of current tree species and the potential of non-local species to thrive.

Previous research has explored tree fitness under warming climates, but field-based information on long-term performance is limited. The report proposes examining established non-local tree plantations created over the last fifty years in northwest B.C. These plantations were not intended as assisted migration or genecology trials, but they offer a unique opportunity to study how these off-site species have coped with changing and non-native environments. Off-site species like Interior Douglas fir, Coastal Douglas fir, Western larch, and Ponderosa pine were planted outside their natural ranges.

The project aims to investigate the survival and growth of off-site tree species in northwest B.C. over the past five decades. Comparing this information with data from local species will establish baseline data for developing assisted migration guidelines. This research builds on earlier modeling efforts that sought to understand how tree species adapt to a changing climate.