APPLICATION OF THE PIPE MODEL-THEORY TO NONDESTRUCTIVE ESTIMATION OF LEAF BIOMASS AND LEAF-AREA OF PRUNED AGROFORESTRY TREES

The relationship of branch cross sectional area (CS) to leaf biomass ( LM) and leaf area (LA) was studied in three agroforestry tree species, Calliandra calothyrsus Maissn., Erythrina berteroana Urban and Erythr ina poeppigiana (Walpers) O.F. Cook, to develop a non-destructive meth od for the estimation of LM and LA for trees managed with periodic pru ning. Variation in these relationships was observed according to the b ifurcation level and, in the Erythrina spp., by clone. All the relatio nships were linear except the CS-LM relation in small branches of E. p oeppigiana, where it was initially exponential. At main branch level t he relationship of CS to LM and LA was linear in all cases but the reg ression parameter values varied between species and clones, with deter mination coefficient (R2) 0.88-0.99. It was concluded that the ratio o f main branch CS to LM and LA can be used for non-destructive estimati on of the latter variables. The method has the additional benefit that the regression parameter value reflects the allocation of dry matter within a tree and, consequently, may give indications about its possib le uses in different agroforestry systems.