In fiscal year 2020-2021, our Forest Program helped 24 residents with projects incorporating weed removal, tree thinning, and native plant establishment to improve the health of 102 acres of forest land. We helped an additional 11 residents with planning and technical assistance such as developing a forest stewardship plan for their land.
Our most exciting projects involved creating ¼- to 2-acre clearings in younger deciduous forests to allow newly planted conifers to grow. Standing in the middle of one of these forest gaps on a warm spring day, the air can be positively humming with all the pollinators visiting the many native shrubs blooming in response to the greater light. The young conifers planted also shoot up vigorously through the brush thanks to the bright, yet protected, conditions created by the forest gap.
Another very exciting multi-year project of the Forestry Program aims to convert about 12 acres of feral English holly farm back into a diverse forest ecosystem. Removing this extent of mature English holly trees was an enormous feat accomplished two years ago, and we are now gearing up to plant the site back to native trees and shrubs.
In September of 2020, we completed the Forest Understory Vegetation Enhancement Project study. In this project, we tested the effectiveness of various methods of establishing native herbaceous forest floor plants from seed. Seeding followed removal of invasive weeds such as English ivy, vinca, and Armenian blackberry, and in some cases thinning of forest overstory to allow more light to reach the forest floor.
We found that as long as the forest received the proper site preparation before sowing seed, including weed removal, thinning where needed, and raking away duff and fallen leaves, the native seed mix germinated and grew successfully. In areas where a diverse native understory was successfully established, introduced plants were more effectively prevented from colonizing and dominating the area.
Soil health also played an important role in supporting the growth of native herbaceous seedlings. Sites with greater tree diversity including both deciduous and coniferous trees tended to have better soil health, and thus a more vigorous forest understory, than the forests comprised of even-aged Douglas-fir monoculture. This project was generously supported by a Conservation Innovation Grant provided by the U.S. Department of Agriculture Natural Resources Conservation Service. To learn more about this study and the recommendations it helped inform, visit our webpage: https://wmswcd.org/projects/forest-understory-vegetation-enhancement-project/