Science for productive forests: Improving reforestation
As agency crews replant millions of acres and billions of trees following increasingly severe wildfires and other disturbances, reforestation science ensures seedlings thrive. This means the agency can spend tree planting resources wisely and ensure timber-producing trees survive to harvest.
Plants growing at the Coeur d'Alene Nursery.
The agency’s target plant concept ensures that we plant the right trees, in the right place, at the right time. By considering connections among seed sources, nursery practices, seedling characteristics, and post-planting growth, the concept helps managers ensure the survival and economic feasibility of the next generation of trees. And since conditions differ across the nation, agency researchers offer geographically relevant reforestation techniques. Researchers in California have shown how using the right tools in the right places can enhance productivity and growth for ponderosa pine during reforestation.
With REGEN MAPPER, forest managers can assess and prioritize planting sites following wildfire and other disturbances. This science-based, agency-developed tool helps users determine the probability of natural seedling regeneration, the distance between roads and planting sites, and the costs and benefits of planting in different places.
Improving the success of nursery-grown seedlings enables managers to use resources wisely. That is why agency scientists are finding ways to condition ponderosa pine seedlings—which survive only a quarter of the time when planted on disturbed sites in the Southwest—to increase their tolerance to drought. Our scientists also found that seedlings survive nearly twice as often when planted on north aspects. They developed recommendations for managers, such as planting seedlings in depressions or in the shade of other objects, based on this research.
Pre-planting site conditions at the Burnt Creek site.
When severe fires defoliate large areas, bare patches may convert to grasslands or shrublands if trees do not naturally regenerate. The Southern Rockies Reforestation Tool helps managers find suitable sites for ponderosa pine and Douglas-fir seedlings after wildfire and prevent conversion of forestland.
Agency research is showing ways to improve mixed-species reforestation in productive California timberlands. Distributing single-species patchworks over broad landscapes may be more efficient, according to the research, compared to planting tree species mixtures within stands.
Agency researchers have partnered with Pacific Northwest national forests to test the best post-fire restoration techniques. Some techniques involve logging to remove dead trees and detritus from forests, ensuring they don’t become fuel for the next fire.
Forest Service scientists developed a genetic database for coastal Douglas-fir that identifies genes conferring disease tolerance and climate adaptation. The database aids managers and breeders as they inventory and track trees in orchards and reforestation plots. And because climate conditions can shift, our scientists established the Experimental Network for Assisted Migration and Establishment Silviculture across sites in California, Oregon, and Washington. At these sites, scientists evaluate assisted population migration and novel silvicultural practices managers might use to reforest in changing conditions.
Reforesters across the eastern United States rely on agency science that identifies which trees to plant where and how to ensure trees survive and thrive. Researchers have also developed the Desired Regeneration through Assisted Migration project, which helps managers evaluate reforestation strategies, from seed sourcing to field testing, that anticipate future conditions.
