Efficiency Of Sawmilling Technology And Lumber Recovery In Kericho County, Kenya

Abstract

Conservation of forests is slowly shifting into a more proactive approach such as efficient lumber conversion in Sawmills. Traditional lumber conversion of Kenyan wood species has heavily relied on chainsaws that have low lumber recovery. There’s need therefore to explore the use of modern Sawmilling machinery in lumber conversion that produces low residues and wastage and hence high recovery. The turnover of log supply in saw mills increases with poor conversion techniques due to high wastages resulting to harvesting trees above the specific annual allowable cuts. Utility efficiency can lead to relative conservation. It is against this background that this study looked into the production capacity, efficiency and recovery rates of Cupressus lusitanica and Pinus patula lumber from selected Wood-mizer (LT15, 20 and 40) Sawmilling machinery in Kericho County, Kenya. Logs delivered to each respective Sawmill yard were categorized into ten diameter classes from 10 to 59cm for both species. Volume of four logs from each class and species was evaluated using Huber’s formula and converted using through and through sawing technique into lumber. Volume of the lumber pieces and residues obtained were measured. The time taken during the conversion process was also recorded in order to determine the efficiency and lumber production capacity of each Sawmill machines. Data were systematically analyzed for relations using descriptive statistics and means through paired sample t-test in SPSS. The study identified a total of 54 registered and prequalified Sawmills (four large scale, 12 medium scale and 38 small scale) located within Kericho County. 30% of these Sawmills are located around Kericho town and 22% in Londiani, with 89.4% having been in operation for more than 10 years. 74.4% of the Sawmills had only one primary conversion machine in comparison with 25.6% who had 2-4 machines and on average five (5) employees. 42.6% of the Sawmills operate up to 8 hours daily while 6.4% operate between 5 and 12 hours daily. Sixty percent (60%) of the Sawmills are LT15, 26.7% (LT20) and 13.3% (LT40). Conversion efficiency of Wood-mizer LT15 was classified as low (48.3%), in comparison with LT20 which was classified as moderate (41.9%) and LT40 as high (60%). Recovery of C. lusitanica gave average empirical values of 43% for Wood-mizer LT15, 49% for Wood-mizer LT20 and 53% for Wood-mizer LT40. Recovery of P. patula gave average empirical values of 39% for Wood-mizer LT15, 34% for Wood-mizer LT20 and 60% for Wood-mizer LT40. LT40 gave the highest recovery rates (74% and 87%) for different top diameter classes of C. lusitanica and P. patula respectively. P. patula produced the most residues at 61% and 66% compared to C. lusitanica at 57% and 51% per log volume for LT15 and LT20 respectively but less from LT40 (47% for C. lusitanica and 40% for P. patula logs. Wood-mizer LT40 recorded the highest daily (8 hours) production capacity for both C. lusitanica and P. patula (15.9 m3 /day and 16.2 m3 /day) respectively. This was followed by Wood-mizer LT20 at 11.2 m3 / day and 9.6 m3 /day for C. lusitanica and P. patula respectively. Wood-mizer LT15 had the least production capacities of 8.8 m3 / day and 9.9 m3 / day for C. lusitanica and P. patula respectively. These results suggest adoption of the selected Wood mizer Sawmill machinery in Kenya for sustainable forest resource management.