Forest Science Program

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Forest tree genetic conservation status report 2: genetic conservation status of operational tree species

Author(s) or contact(s): J. Krakowski, C. Chourmouzis, A.D. Yanchuk, D. Kolotelo, A. Hamann, and S.N. Aitken
Source: Forest Science Program
Subject: Forest Genetics
Series: Technical Report
Other details:  Published 2009. Hardcopy is available.


The native tree species of British Columbia provide a vast range of economic benefits and ecological services. Conserving genetic diversity in these species is critical for maintaining the ability of populations to adapt to new conditions, and for safeguarding genetic resources from which tree breeders can select to meet new challenges or objectives. Genetic conservation of forest trees is achieved in British Columbia for all indigenous species through the protection of populations in situ in parks and protected areas. The status of tree species in situ is documented in a companion report, Forest tree genetic conservation status report 1: In situ conservation status of all indigenous British Columbia species (Chourmouzis et al. 2009).

For species of economic importance that have genetic management and tree improvement programs, there are also extensive genetic resources archived ex situ, primarily in seed collections in long-term storage, and inter situ, in provenance and progeny trials. Historically, seed bank conservation samples have been obtained from the surplus remaining for each operational seedlot, after testing. Prior to December 2003, operational seedlots represented collections from over 50 individuals in an area. To support a more strategic acquisition approach subsequent collections focussed on obtaining at least three samples per target species within identified biogeoclimatic (BGC) zones. The strategy is to populate the full matrix of species-zone occurrences with at least three samples per cell for conservation collections. This represents a highly efficient, robust conservation approach: 100 grams of hybrid white spruce seed could contain up to 50,000 unique genotypes, and ex situ collections are not susceptible to climate change impacts, as genetic resources in situ and inter situ sites are; however, stocks must be periodically replenished because long-term storage may reduce seed viability.

This report summarizes the in situ, ex situ, and inter situ genetic conservation status of commercial forest tree species in British Columbia that have genetic management and tree improvement programs. These eight conifers have breeding programs supported by inter situ trials established for their respective seed planning zones (SPZs) and/or seed planning units (SPUs) (Snetsinger 2004).

This report expands on the assessments of Yanchuk and Lester (1996) and Hamann et al. (2004, 2005). These studies used comparable methodology (using the life history traits, forest inventory, protected areas, and utilization) to track in situ conservation status of conifers in British Columbia, and developed systems to prioritize species for conservation efforts. Changes between the previous assessment (Yanchuk and Lester 1996) and this assessment indicate where gaps still exist or where increased genetic conservation and habitat protection have been successful. This analysis has improved precision through the updated forest inventory database, Geographic Information System (GIS) platform, and quantification of effective population sizes (Ne) in reserves. Effective population size is the number of individuals contributing genes to the next generation of the population, based on an idealized set of population genetics assumptions.

Species were ranked in terms of conservation priority using criteria adapted from Yanchuk and Lester (1996), and revised based on international (FAO et al. 2004) and regional information. Ranking criteria used by other programs that assessed plant species were also reviewed to compile the most current and representative set of standards to prioritize these species (IUCN 2001; COSEWIC 2006; NatureServe 20081). Gaps in conservation can highlight areas to focus on for prioritization of in situ reserve establishment or management, ex situ seed collections, or inter situ representation. For the most part, population diversity of British Columbia's native tree species is well represented across the spectrum of conservation vehicles. Species at the margins of their ranges, and those with scattered distributions, require some verification (e.g., western white pine, western larch in the Nelson High and East Kootenay SPU's, Sitka spruce in the Nass-Skeena Transition) in situ. Only three species-SPU combinations had insufficient ex situ collections. Most commercially marginal SPUs have low or no inter situ representation.

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Updated January 29, 2010