Establishing northern red oak on a degraded upland site in Northeastern Pennsylvania: influence of seedling pedigree and seedling quality


Cornelia Pinchot, Tom Hall, Scott Schlarbaum, Arnold Saxton, and James Bailey

(CP) Northern Research Station,, (TH) Pennsylvania Bureau of Forestry,, (SS) Tennessee Tree Improvement Program, The University of Tennessee, Knoxville,, (AS) Department of Animal Science, The University of Tennessee, Knoxville,, and (JB) PA Bureau of Forestry, retired

Abstract – Augmentation plantings using large oak seedlings of regional pedigreed sources may promote superior survival and growth as compared to direct seeding or standard nursery seedling material. This study evaluated the survival and growth of planted 1-0 northern red oak (Quercus rubra L.) seedlings among: 1) eleven pedigreed families and one bulked acorn seedlot and 2) three seedling size classes; premium, poor, and cull. Seedlings were planted in April, 2005 in a 2-hectare deer exclosure in a failed clearcut made in the mid-1970’s on the Delaware State Forest in Pike County, Pennsylvania. Factors that contributed to oak regeneration failure included intensive browsing by deer and invasive plant competition from hay-scented fern (Dennstaedia punctilobula) and sweetfern (Comptonia peregrine). The soils at the site are of the Manlius Series characterized as strongly acidic, rocky-silt loam with low soil moisture retention. After seven years all but two pedigreed families had better survival (84% on average) than the bulked seedlot (54% on average; P < 0.0001). Height and root collar diameter (RCD) of the pedigreed families were each 1.5 times larger on average than the bulked seedlot (P < 0.0001 for each). Height and RCD of premium seedlings were greater in four and seven of the families, respectively (P = 0.01; P < 0.0001) than either poor or cull seedlings. These results suggest that keeping seedlots separated by maternal source facilitates selection of superior families for planting and future breeding over a wider range of regional genetic sources.