Nursery plots sown with the Summit Precision Seeder and the Oyjord Seeder were compared with plots oversown and hand thinned to desired spacings. We studied 26 seedlots of nine conifer species at five Forest Service, U.S. Department of Agriculture, nurseries. Results varied with nursery, species, and seed characteristics. Thinned plots produced less clumping and fewer gaps between seedlings, but showed little or no difference in seedling size, nor in the number of acceptable seedlings.
United States Department of Agriculture, Forest Service, "Effects of Seeder Design and Seed Placement on Seedling Size and Cull Rates at Western Forest Nurseries" (1992). Forestry. Paper 57.