Use seeds, germplasm, and other genetic material from across a greater geographic range

EASTERN: Planted seedlings typically have greater survival when they originate from local seed sources, but local seed sources may no longer produce the best adapted seedlings if the governing environmental factors change. Using seed zones that change over time and are based on regional analyses of climate change data may provide better seed sources than static seed zones. This may entail importing genetic stock from locations ranging from nearby to substantially distant in order to introduce plants that are expected to be better adapted to current or future climatological conditions. At the same time, ecoregional and political boundaries may continue to restrict the distance from which new species or genotypes may be imported. This strategy may require communicating with policy-makers to reevaluate seed zone sizes and rules governing the movement of seed stocks. It is important to note that although many environmental factors may match seedlings to geographic areas, limitations such as cold tolerance may remain. It is also important to take the necessary precautions to avoid introducing a new invasive species.

WESTERN: Planted seedlings typically have greater survival when they originate from local seed sources, but local seed sources may no longer produce the best adapted seedlings if the governing environmental factors change. Using seed zones that change over time and are based on regional analyses of climate change data may provide better seed sources than static seed zones. This may entail importing genetic stock from locations ranging from nearby to substantially distant in order to introduce plants that are expected to be better adapted to current or future climatological conditions. Though there are many uncertainties, research on potential risks, benefits, and trade-offs of “assisted gene flow” are rapidly increasing for forest tree species. At the same time, ecoregional and political boundaries may continue to restrict the distance from which genotypes (or species) may be imported. This strategy may require communicating with policymakers to reevaluate seed zone sizes and rules governing the movement of seed stocks. It is important to note that although many environmental factors may match seedlings to geographic areas, limitations such as cold tolerance may remain. It is also important to take the necessary precautions to avoid introducing a new invasive species.

Greater genetic diversity may help species adjust to new conditions or sites by increasing the likelihood that some individuals within a species will be able to withstand climate-induced stressors. Current guidelines for management of tree genes generally promote the conservation of local gene pools, restrict transfer of germplasm, and define small seed zones to minimize contamination between pools. A changing climate may require new guidelines that accommodate shifting seed zones and promote more options for increasing genetic diversity. Actions to enhance genetic diversity could be timed to occur after large-scale disturbances to take advantage of regeneration and establishment phases. Approaches under this strategy are best implemented with great caution, considering the uncertainties inherent in climate change, the sparse record of previous examples, the ecological and social suitability of particular locations, and continued uncertainties of forest response.