Evaluation of protective devices for the direct seeding of longleaf pine (Pinus palustris)

Abstract

Most tree species, including longleaf pine (Pinus palustris Mill.; LLP) are established by planting seedlings during reforestation. Direct seeding could be a viable alternative; however, seed predation by various animals might be an impediment. While LLP are typically planted using nursery-grown plugs with high survival rates, planting these in certain sites may be difficult, and the appropriate genotype for a given site may not always be available. We expect that LLP seed and early seedling survival might reach acceptable rates when directly planted seeds are protected by shelters. We thus evaluated the effectiveness of degradable shelters (Seed Crowns™) for use in direct seeding of LLP. This project was carried out at two sites in middle Georgia and four sites on the Berry College campus near Rome, Georgia. At the middle Georgia sites, seeds were planted within shelters (no unprotected controls) across five subplots with varying numbers of planting spots at each site as a general test of field implementation. At Berry College, from 65 to 80 shelters were installed at each site along with 15 to 20 control spots (unprotected seeds). At the two middle Georgia sites respectively, 35 % and 77 % of seeds planted were living seedlings after ∼5 months and 52 % and 90 % of spots had at least one survivor. Across the Berry College sites after 5 months, sheltered seeds had an 86 %, 14 %, and 24 % improvement over controls in seeds (or seed coats) present, seedlings alive, and spots with at least one survivor, respectively. Taken together, these results suggest that direct seedling using these shelters may be a viable option for restoring longleaf pines when other considerations prevent or disfavor the use of containerized seedlings.