Restoring Forest Habitat Using Assisted Migration as a Climate Change Adaption

Rapid climate change alters the conditions for which tree species can migrate successfully. Restoration efforts are vital for our future forests to ensure healthy and sustainable forests. Assisted migration is a restoration practice that can speed up trees' slow migration process, promoting resilient forests. This study assessed how genotypes from California, Oregon, and Washington nursery stock plants would succeed in a Western Washington-assisted population migration project. Additionally, we want to evaluate how transfer to new soil microbiomes will affect ectomycorrhizal (ECM), a fungus that forms symbiotic relationships with certain plant root tips. To achieve this, in January 2022, 900 plants (75 per species or 25 per genotype) of Douglas-fir (P. menziesii ssp.menziesii), Shore pine (Pinus contorta var. contorta), and Garry oak (Quercus garryana) were divided into four 0.2 hectare plots, three with irrigation and one without irrigation. ECM presence was assessed via root tip collection before planting. Upon planting, height and basal diameter were taken. In May 2023, height, basal diameter, and survival were recorded. In November 2022, ECM presence was assessed by collecting root tips from 10 trees per genotype, followed by DNA sequencing of the fungal internal transcribed spacer (ITS) region. The results of this study provide baseline data for a project that will be followed over the next decade. Initial findings suggest that some tree genotypes performed better than others. This study also confirmed that most ECM could maintain functional mycorrhizas in Washington restoration soils for an assisted population migration project when migrated from California and Oregon.