Assessing genetic variation of forest tree species at risk
PARTNERS: North Carolina State University Department of Forestry and Environmental Resources; USDA Forest Service National Forests Genetics Laboratory, Forest Health Monitoring Program, Forest Health Protection, and Southern Institute of Forest Genetics; United States Department of Interior Bureau of Land Management
SUMMARY: Many forest tree species and populations face serious threats to their long-term viability, most seriously from insect and disease infestation and from the effects of climate change. To conserve the genetic foundation tree species need to survive and adapt in the face of these threats, forest management decisions must consider how genetic diversity is distributed across species’ ranges. A cooperating scientist from North Carolina State University (NCSU) is the lead analyst for two range-wide genetic variation studies of species with large distributions: eastern hemlock, which is being decimated by an exotic insect, and ponderosa pine, a species with isolated populations of special concern given their susceptibility to climate change, development, and bark beetles.
Results from both studies are already influencing management decisions. Characterization of the genetic diversity and structure of the eastern hemlock species is guiding NSCU-based Camcore conservation cooperative’s seed collections from genetically significant eastern hemlock populations. As the ponderosa pine study uncovers evolutionary relationships among species varieties and assesses genetic variation of several small and isolated populations, the Bureau of Land Management is utilizing results for management activities in the western United States. The Forest Service’s National Forest System will also use study results to help guide gene conservation and seed transfer strategies.
Above left: Eastern hemlock is an important species in riparian areas; this stand is along a creek at South Mountains State Park in North Carolina. Eastern hemlock is experiencing severe mortality from the exotic hemlock woolly adelgid across much of its distribution. Photo by Kevin Potter.
Above right: Ponderosa pine is an ecologically and economically important tree species across much of the western United States. It faces threats from an epidemic of native bark beetles and from climate change. This ponderosa pine in northern Colorado is infested by mountain pine beetle. Photo by Kevin Potter.
EFETAC'S ROLE: The project is supported by Eastern Threat Center funding.
PROGRESS: The range-wide genetic variation study of eastern hemlock, using polymorphic microsatellite markers, was published in 2012. Researchers are using the results of this study, along with climate change projections developed by the ForeCASTS project and with hemlock woolly adelgid presence data, to assess long-term genetic risk to eastern hemlock populations.
Mitochondrial DNA haplotypes were identified from more than 100 ponderosa pine populations, allowing researchers to detect long-term genetic divergence among groups of populations. A journal article describing these results was published in 2013. Additional microsatellite marker and isozyme protein marker work is under way to assess genetic variation among ponderosa pine populations.
Previously published work focused on other at-risk forest tree species, including two Southern Appalachian endemic species, Carolina hemlock and Fraser fir, and pine species from Mexico and central America.
This research has been described in a number of papers and presentations.
CONTACT: Kevin Potter, NCSU Department of Forestry and Environmental Resources, firstname.lastname@example.org or (919) 549-4071
Updated January 2014