TAPER AND VOLUME FUNCTIONS FOR EUCALYPTUS GRANDIS IN ZIMBABWE

Abstract

A polynomial taper curve and a logarithmic volume function for plantation Eucalyptus grandis in Zimbabwe were developed from data collected from 589 sample trees at four different sites. The sites covered the whole range of sites where the species is currently grown on a commercial basis. The parameters measured were diameters underbark at stump height and at every 1.5 m
along the stem, dbh overbark and underbark, stump height and top section length. Volume predictions by the taper curve and the new volume function were compared with predictions by the old volume function. The polynomial taper curve provided the best volume predictions followed by the new volume function. The new volume function provided better estimates than the old volume function for trees<30 cm dbh. The old volume function underestimated volumes over all diameter ranges but provided more reliable estimates than the new volume function for trees > 30 cm dbh. The new volume function was recommended for use in pole production while the taper curve was recommended for use in both pole and sawlog production.