The use of shoot dimensions to estimate the leaf mass or shoot area of certain indigenous trees in Rhodesia.

Abstract

Various shoot dimensions such as height, stem diameter, canopy spread, and number of stems were measured on a sample comprising various sizes of trees of Colophospermum mopane, and samples comprising various sizes of coppice clumps of Brachystegia spiciformis and B. boehmii. Concurrently, the leaf mass of each of the C. mopane trees, both above and below a height of 2 m from ground level, and the leaf area of each of the B. spiciformis and B. boehmii clumps was measured.The data were used to derive regression equations relating dimensions to leaf mass and leaf area. The relationships were best expressed by means of logarithmic transformation of both dependent and independent variables. In practice there are disadvantages in the use of logarithmic transformations and the use of untransformed variables or non-logarithmic transformation is recommended. However, for estimating leaf mass below 2 m in C. mopane it was found desirable to use a semi-logarithmic equation with the logarithm of the mass ratio (leaf mass below 2 m per total leaf mass) as the dependent variable.It is necessary to devise fresh regression equations for each set of circumstances. A method involving stratified sampling is suggested.

Keywords: botany; brachystegia boehmii; brachystegia spiciformis; canopy spread; colophospermum mopane; dimensions; height; indigenous trees; leaf area; leaf mass; leaves; mass; mopane; nuanetsi experiment station; rhodesia; shoot area; trees; zimbabwe