Effect of Plant Densities and Root Pruning on Seedling Quality of Three Hardwood Species

Nursery seed bed density (3, 6 and 9 seedlings/ft2) with or without root pruning affected the seedling morphology bud did not affect the root growth potential (RGP) in a consistent fashion in white oak, red oak and black walnut seedlings. Treatment response varied with nursery and species. Seedlings had greater root collar diameter (RCD) at lower plant density (3 seedlings/ft2) with or without root pruning in oaks but treatments did not affect the RCD of black walnut. Root pruning was found beneficial for oaks but harmful for black walnut seedling growth. Oaks had better RGP when grown at lower plant density (3 seedlings/ft2) with or without root pruning but it was not affected in black walnut seedlings. Correlation studies showed a positive and significant correlation among various morphological and root growth traits. A strong correlation was observed between new shoot dry weight and RGP and between lateral root dry weight and RGP in all three species. Tap root dry weight was significantly correlated to RGP in black walnut but not in oaks.