Gaps Remain in Protecting BC's Trees

More rare ecosystems in British Columbia's Bunchgrass, Ponderosa Pine and Interior Douglas-fir biogeoclimatic zones gained protected status during the 1990s. Elsewhere in BC, however, rare and species-rich ecosystems tend to remain insufficiently protected, particularly for species restricted to small areas such as Garry oak and arbutus.

Amid the 226 combinations of tree species and ecosystems examined using species distribution maps, several conservation gaps stand out. Notable among commercial species is Douglas-fir in the Sub-boreal Pine-Spruce biogeoclimatic zone, where only 39 ha is protected in reserves. Only one reserve exceeds the 10 ha minimum considered adequate to maintain a population.

Even worse off are western white pine in the Mountain Spruce zone and limber pine in the Interior Douglas-fir zone where no reserves larger than 2.5 ha exist for these species. Overall, though, 80 percent of tree populations are sufficiently protected in at least three reserves.

Big beneficiaries of protected area expansion during the 1990s are trees confined to northeastern BC: jack pine, tamarack and Alaska paper birch. In south-coastal BC, more vine maple, bigleaf maple, grand fir and Pacific dogwood, acquired protection.

Researchers analyzed how well 830 protected areas span the ecological and genetic variation of BC's tree species. The results help establish priorities for field-checking possible gaps.