How planting method, weed abatement, and herbivory affect afforestation success.

摘要

The success of upland and riparian afforestation depends on landowners making informed decisions about key factors such as the quality of seedlings (species, size, and root stock), planting technique, site preparation, weed and herbivore control, and planting pattern for the plantation. We show here that the short-term (1 year) and longer-term (3 year) effects on seedling survivorship and growth due to planting technique (dibble-bar versus auger) did not differ significantly for the five test species, viz., red maple (Acer rubrum), eastern redbud (Cercis canadensis), green ash (Fraxinus pennsylvanica), sweetbay magnolia (Magnolia virginiana), and sweet gum (Liquidambar styraciflua). Weed treatment (tree mats, initial herbicide application, and annual herbicide application) also failed to significantly increase seedling survival or growth, a result hypothesized to be caused by high moisture and nutrient content of soils on the site. In contrast, tree shelters significantly increased seedling survival and growth after 1 and 3 years. For some species, 3-year survival was up to five-fold higher with shelters. Long-term weed control increased survivorship of sheltered seedlings but decreased survivorship for those without shelters because of increased exposure to deer. For this site, successful afforestation depends more on protecting seedlings from herbivory with tree shelters than on either the method of planting or the method of controlling weeds..