Extent, distribution and causes of defects in soft wood plantation in Kenya

Abstract

This paper reports on the magnitude of defects in Cupressus lusitanica and their distribution. The study analysed data collected from all forest regions where defects were identified. Results indicated that defects in sawn timber were reported in most Cupressus lusitanica (Cypress) plantations, ranging between 23 and 37%.  On the average, over 91 % of all the defects observed were a combination of heart rot and oemida gahani, a common pest in Cypress wood. Peculiar cases (0.4%) involving termite attack on standing trees was observed in western region. The magnitude of the defects significantly differed among different regions. Much of the damage was attributed to monkeys, particularly in Mau and central Kenya, while in Mt. Kenya and Aberdare, damage to trees were associated with buffaloes and elephants. The age of the trees had a significant influence on the magnitude of defects even within the same region. The study recommended  need to develop strategies to reduce the primary causes of defects and increase the quality of raw materials available for the wood industry. Further, there is need to improve silvicultural treatment and harvest trees at optimum rotation age to avoid extended damage of the wood in case there is initial attack causing any of the defects. The study further recommends diversification of species and introduction of bamboo as an industrial material particularly in high altitude areas.