In Situ Gene Conservation of Six Conifers in Western Washington and Oregon

A gap analysis was conducted to evaluate the extent to which genetic resources are conserved in situ in protected areas for six conifer species in the Pacific Northwest (Sitka spruce, sugar pine, western white pine, ponderosa pine, western redcedar, and western hemlock). The gap analysis involved producing a GIS database detailing the location of protected areas and the distribution and abundance of tree species as inferred from data on potential plant association groups, actual plant associations, and actual land cover type. We used two schemes for stratifying the distribution of each species into genetic populations for gap analysis: seed zones and ecoregions. The results show that most seed zones and ecoregions contain at least 5,000 mature individuals in protected areas, indicating strong in situ gene conservation. Protection is less complete, however, for western white pine in the Puget lowlands, where urbanization and disease have reduced populations below safe levels. These populations represent the highest priority for additional gene conservation. Other species and areas warranting further evaluation include Sitka spruce in some parts of the Puget lowlands, remnant western white pine stands in the Oregon Coast Range, and sugar pine within the white pine blister rust zone.