Leaf biomass and leaf area equations for three planted trees in Iran

Abstract

Leaf area (LA) and leaf biomass (LB) are important variables for most physiological, horticultural and agronomic studies involving plant growth, development rate, radiation use efficiency, and water or nutrient use. Measuring these variables need destructive and aggressive sampling. Fortunately, evolving allometric equations can help for low cost and non-destructive estimation of such variables. The aims of this study are Estimate, compare and develop allometric models of LA and LB per tree and per stand for Alnus subcordata (AS), Populus deltoides (PD) and Taxodium distichum (TD) plantations. We selected 12 sample trees in each stand. Leaf Fresh weight of randomly selected branches was weighted in the field. Branch-level LA was modeled as a function of branch diameter (R 2 > 0.8) and total fresh weight of LB has been calculated for each sampled tree. For each species, 100 leaves from all canopy directions of trees were randomly selected and transported to the laboratory. At the lab, leaf area has been measured using leaf area meter. Allometric equations were derived using regression analysis. For all species, derived equations showed high accuracy (R 2 ranged from 0.837 to 0.947). However, with respect to mean square error, power regression equations (individual leaf area = a(L×W)b and LA or LB = a DBH b ) are best models to estimate Individual Leaf Area, LA, and LB of AS, PD, and PD. The highest LAI was in the order of 16.9 > 5.5 > 4.5 for AS, PD, and TD, respectively.