Partitioning of nitrogen, phosphorus, and potassium in redbud trees

Elemental absorption and allocation patterns of a tree species create insight for fertility management regimes. Allometric equations for young redbud (Cercis canadensis L.) trees were developed that accurately estimate weights of selected tree components. Absorption and allocation patterns of nitrogen (N), phosphorus (P), and potassium (K) were characterized for young redbud trees their second year following transplanting. Treatments were a factorial combination of urea rate and phenological growth stage. Urea application increased leaf N concentration when sampled at budbreak, but not at other sample times. Phosphorus and K concentrations were not affected by N treatment. Absorption and allocation patterns of N, P and K indicated that young redbud trees rely primarily on current year's absorption of these nutrients rather than conservation from leaves and storage pools of labile nutrients. Allocation patterns of N, P and K are consistent with an early succession species, and suggest that tree growth is strongly correlated with available nutrients if environmental conditions favor growth.

► Allometric equations were developed that accurately estimate component weights of young redbud trees. ► Little, if any, nitrogen, phosphorus and potassium are conserved from senescing redbud leaves. ► Redbuds depend on current season absorption rather than labile storage pools for nitrogen, phosphorus and potassium needs. ► Redbud patterns of nutrient allocation are consistent with an early succession species.