The effect of planting density on the stem form of Pinus patula trees

Abstract

In this study the effect of planting density on the stem form of Pinus patula trees was investigated. Four different spacing treatments of 403, 1 097, 1  808, and 2 981 stems per hectare (spha), and four stem form properties viz. stem deviation, taper, sinuosity and ovality, were assessed on the lower nine metres of the tree stem. The results showed that spacing treatment had a significant effect on all four stem form characteristics. Over the lower nine metres of the stem, the lower spacing treatments (403 and 1 097 spha) had mean stem deviations of 132.1 mm and 109.3 mm respectively, while the higher planting densities (1 808 and 2 981 spha) had mean stem deviations of 76.4 mm and 82.1 mm respectively. Sinuosity and taper also had a decreasing trend from 403 spha to 2 981 spha. Ovality, on the other hand, increased with increasing planting density and also increased with increasing height along the tree stem.

Keywords: ovality, Pinus patula, planting density, sinuosity, stem deviation, stem form, taper