Silviculture and Reforestation
Returning the American chestnut to the forest is TACF’s ultimate restoration goal. While we continue to work to develop trees with enough blight resistance to make that goal a reality, we can start to prepare by experimenting with silvicultural practices and reforestation methods to better understand the best ways to approach species reintroduction. As a first step, forest progeny testing began on a wide range of sites in 2011 in IN, TN and WV with the US Forest Service and private industry. These test plantings help us refine our breeding selections by allowing us to observe the performance of their offspring under forested conditions. In addition, those forest progeny tests with trees robust enough to survive blight and compete with the surrounding native vegetation may act as reintroduction cells, from which the species can start to spread back into the forest unassisted.
Silvicultural and reintroduction trials provide an opportunity to experiment with planting chestnuts on forested sites. Silvicultural trials allow us to learn how chestnut grows under different forest management scenarios. Such trials have examined planting in gaps of various sizes, clearcuts, closed canopy, shelterwoods, and multi-step management prescriptions. For example, a Green Mountain National Forest planting, managed in partnership with the US Forest Service and University of Vermont, looks at chestnut growth, cold tolerance, and winter injury under three canopy treatments – open, partial, and closed canopy. Reintroduction trials differ slightly in that these plantings look at techniques for establishment such as planting stock type (seed vs. bare root vs. containerized seedlings), planting density (spacing between trees) and time of planting (fall vs. spring). They also include site preparation, methods of protection from wildlife, and fertilization. Often reintroduction and silvicultural trials go hand-in-hand, for instance a North Carolina State University study examined growth and survival differences between chestnuts planted in an open canopy vs. a shelterwood, with and without fertilization at the time of establishment.
Mined land reforestation plantings represent another avenue to help TACF achieve its research and restoration goals. By working with the Appalachian Regional Reforestation Initiative, Green Forests Work, and other partners, TACF has assisted in the planting of more than 1.8 million seedlings and the reforestation of nearly 3,000 acres on both publicly and privately-owned mined lands in eight states since 2009. By restoring degraded lands to native forest types, mined land plantings meet multiple objectives. These plantings not only improve wildlife habitat and decrease forest fragmentation, but also result in improved air and water quality, increased carbon sequestration, invasive exotic species suppression, and economic benefits. Reintroduction trials on mined lands include progeny tests of TACF’s potentially blight resistant chestnuts, as well as experiments to examine how chestnuts grow and survive when compared to other commonly planted native species in a mixed hardwood reforestation setting. As with forest progeny tests, it is hoped that chestnuts with the highest levels of blight resistance and vigorous growth will contribute to chestnut regeneration in surrounding areas.