Within BC’s forests, Douglas-fir trees are iconic, reaching the largest size of any trees other than redwoods, providing habitat for biodiversity and generating high-quality forest products.

There are two main lineages of Douglas-fir recognised in BC, Pseudotsuga menziesii var. menziesii (coastal Douglas-fir), found in the West of BC, and Pseudotsuga menziesii var. glauca (interior Douglas-fir), found in the southern interior of BC. The lineages are phenotypically and ecologically distinct, so much so that they are subject to distinct management policies and maintained in separate breeding programs by the Ministry of Forests. Combined lumber harvest across the two lineages makes up as much as 22% of BC’s yearly timber harvest; the majority of that comes from the interior of BC.

With climate change and the adoption of Climate-Based Seed Transfer policy in BC, planting of interior Douglas-fir is increasing as suitable habitat expands. Despite the importance of these trees to the province’s economy and culture, little is known about the genomic differences that may distinguish the two lineages. Furthermore, given the size and repetitive nature of the species’ genome, applying genomic technologies is still very expensive and challenging.

With this project, the research team aims to develop genomic resources for interior Douglas-fir and compare its genome with the coastal variety. They will then explore methods to multiplex DNA samples (meaning to combine many separate DNA samples into a single batch to be processed by a sequencing machine all at once) from thousands of trees to reduce the sequencing costs for individual trees. These approaches will be tested on needle tissue from a recently completed drought tolerance experiment on both lineages of Douglas-fir as well as samples from the Ministry of Forests’ breeding population of interior Douglas-fir. The results from this study will help identify genomic regions involved in drought tolerance and the methods used in this study can be readily extended to other species of conservation or management concern in BC and around the world.