Response of young black cherry stands to fertilization

Abstract

Twenty fertilizer treatments of different rates and combinations of N, P, and K were established in young black cherry (Prunusserotina Ehrh.) stands that originated after clear-cutting in northwestern Pennsylvania, U.S.A. Height, diameter, and basal area growth rates and foliar nutrient composition were evaluated annually for 5 years thereafter. Nitrogen alone and P in combination with N produced large increases in height, diameter, and basal area growth. The addition of K to N + P treatments produced no additional response. Growth responses were largest during the first 2 years after fertilization, with increases in height and diameter lasting for 4 to 5 years. In year 1, maximum growth rates were reached with 112 kg N/ha and 49 kg P/ha, but 224 kg N/ha and 49 kg P/ha were necessary to sustain responses in following years. Both seedling and sapling stands responded to fertilization with similar absolute annual increases in height and diameter, though absolute basal area response of saplings exceeded that of seedlings owing to large differences in pretreatment diameters. Nitrogen fertilization increased average foliar N from 2.51 to 3.94% in year 1, but this concentration declined sharply thereafter and was at the control level by year 4. Phosphorus fertilization increased average foliar P from 0.12 to 0.21% in year 1, with further increases through year 5. Potassium fertilization increased average foliar K from 1.01 to 1.21% over the 5-year period, though there was considerable year-to-year variation.