Predicting Fertilizer Response in Established Loblolly Pine Plantations With Basal Area and Site Index
Abstract In a wide range of loblolly pine (Pinus taeda L.) plantations, very few of which were suffering from severe nutrient deficiencies, response to fertilization was related to stand conditions. Gross and net volume increment equations were developed using basal area, site index, and fertilizer treatment as predictor variables. Response to fertilization was calculated as the difference between growth estimates for control and fertilized stands at given levels of basal area and site index. Predicted 5-year volume response from fertilization with 100 lbs N/A + 50 lbs P/A is given for a range of basal area and site index levels for both the Coastal Plain and Piedmont regions. The information provided will enable the forest manager to choose stands with the greatest potential for response, and to determine the economic benefits of fertilization.