Pacific Northwest Research Station

One of the first forest genetics studies in the United States launched in 1912 in the Pacific Northwest. Researchers at that time gathered Douglas-fir seeds from various locations in Oregon and Washington, raised the seedlings in a nursery, then transplanted them to places other than where the seeds originated.

The results had wide-ranging impact, revealing a link between seed origin and where the resulting seedlings were likely to thrive. These results led to the delineation of “seed zones,” an essential set of guidelines used for decades in reforestation projects to ensure that newly planted seedlings are suited to local conditions. However, as climates change, these guidelines may no longer be as effective.

Brad St. Clair with the USDA Forest Service, Pacific Northwest Research Station, and colleagues revisited the 1912 study in search of clues to help guide tree planting into the future.

Applying new statistical tools to old data, the scientists found that temperature affected the survival of trees planted in the 1912 study. Douglas-fir planted in areas where the temperature was about 4 ⁰F (2 ⁰C) warmer or colder than where their seed originated did not survive as well as ones planted within that temperature range. Results lead researchers to project that warmer temperatures will have a negative effect on Douglas-fir, while planting seedlings in areas cooler than their native zone may help forests thrive into the next century.