Soil Amendment Effects on Growth and Sprouting Success in a Pennsylvania Northern Red Oak Stand on Extremely Acidic Soils

Abstract

On the Laurel Hill, anecdotal accounts reported coppice regeneration of oaks to be limited. Possible causes of poor sprouting success were large stump size, deer browsing, season of cutting and poor tree vigor. Our study site had been partially cut three years before this study to salvage some northern red oak (Quercus rubra L.) which had died. We attempted to increase Q. rubra vigor, as measured by increasing basal area growth, with soil amendments of 6,600 kg/h dolo-mitic lime, 110 kg/h K2O equivalents and 220 kg/h P2O5 equivalents while accounting for other growth variables. The objective was to improve overall Q. rubra sprouting success by increasing vigor prior to harvest. The soil amendments increased soil available calcium (Ca), magnesium (Mg), potassium (K) and phosphorus (P) and reduced available aluminum (Al). Foliar concentrations of Ca, Mg and K were increased. Basal area increment of treated Q. rubra trees increased by 10 percent and terminal elongation increased by nearly 100 percent. Two years after treatment, the trees were cut during the dormant season and all stumps were protected from deer browsing. After two years, 80 percent of the stumps had sprouted. No effect of lime and fertilizer on the sprouts was found.