Assessing the effects of resin tapping on selected strength properties of pine in Busoga forestry company.

Abstract

Resin tapping is a lucrative practice in Uganda, boosting company profits. It involves incising pine trees to extract resin from their ducts, primarily in Pinus plantations. However, the longer the tapping period (up to five years), the deeper the tree wounds, leading to weaknesses and vulnerability to fires and strong winds. Weakened trees result in low-quality timber products, posing a significant challenge to the strength and durability of the harvested wood. Therefore, this study was carried to investigate the effects of resin tapping on selected strength properties of pine which include basic density, flexural properties (MOR and MOE) and compressive strength parallel to the grain. In this study, trees that had been tapped for four years were purposively selected because the effects would be seen clearly and studied well. The logs were obtained and dimensioned into (20 × 20 × 280) mm for the flexural properties, (20 × 20 × 60) mm for compressive strength parallel to the grain and (20 × 20 × 15) mm for basic density then 45 samples from each objective test were used to carry out the tests. The flexural properties of untapped trees were higher than that of the tapped trees showing no significance (p=0.287) with a mean of 5016Mpa for the tapped wood and 5429Mpa for the untapped wood for the case of MOE. Under MOR, the mean of the tapped wood was 43.4Mpa and 46.2Mpa for the untapped with a p value of 0.596 The compressive strength parallel to the grain was higher in the tapped trees than the untapped tress showing significance (p= 0.000) with a mean of 33.47Mpa for the tapped wood and 28.42Mpa for the untapped wood. The basic density of tapped trees was higher in the tapped tress showing no significance (p=0.975) between the tapped tress and untapped trees with a mean of 86 kg/m3 for the tapped wood and 38kg/m3 for the untapped wood. I finally recommend the timber users to carry out more tests so that the timber can be confirmed for further use like construction and also the grading systems should be advanced to classify the timber well for timber use.