Tropical Development and Research Institute (TDRI)
Abstract
The results of the examination of a sample of Pinus oocarpa, approximately 10 years old, grown in plantations in Uganda are reported and compared with those obtained from a sample grown in its natural habitat, Belize. The sample from Uganda had a wood density of 382 kg m-3 which was much lower than that of the sample from Belize, 530 kg m-3. The Ugandan sample also had a lower resin content and the fibres were shorter, narrower, and thinner-walled. Using the sulphate pulping process, under different conditions the Ugandan sample yielded between 41.8% and 48.4% of pulp with a kappa number from 23.7 to 53.1. Samples of Pinus oocarpa from their natural habitats are reported to yield pulps with properties similar to those of Southern pines from the USA, with high tearing strength, and moderate bursting and tensile strengths. The Ugandan samples yielded pulps with similar bursting and tensile strengths, but low tearing strength. The effects are reported of bleaching the pulp by a four-stage sequence of successive applications of chlorine, sodium hydroxide, sodium hypochlorite and chlorine dioxide. Differences between the Ugandan and Belize samples are principally attributed to the lower age of the former
