Browsing by Author "Mauya, E.W"

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Lumber recovery and production rates of small-scale mobile sawmilling industries in northern Tanzania
(Tanzania Journal of Forestry and Nature Conservation, 2021) Lolila, N.J; Mchelu, H.A; Mauya, E.W; Madundo, S.D
This study was carried out to quantify technical efficiency of mobile sawmills by determining the lumber recovery rates and production rates of two mobile sawmills namely as Wood-Mizer (band saw machine) and Ding-dong (circular saw machine). The study was conducted in Lushoto district, located in the Northern part of Tanzania. The results indicated that Wood-Mizer had lumber recovery of 51.3% and production rate of 0.64m 3 /hr., while Ding-dong had lumber recovery rate of 35.2%, and production rate 0.86m3/hr. Generally, results have shown that both sawmills have reasonable lumber recovery rates and production rates irrespective of the differences between the two, however Wood-Mizer had great conversion efficiency compared to the Ding-dong machine. Considering the reduced supply of saw logs for sustainable forest management, a machine with high conversion efficiency is highly encouraged than machine with high speed of production, thus Wood-Mizer stands to have more chances of applications as compared to Ding-dong machine which had relatively higher production rates. However, we encourage further studies to be conducted with diverse sets of factors associated with economic aspects as well as tree species to have more baseline information on the performance of these two mobile sawmilling machineries.
Modeling productivity and costs of mechanized tree length skidding operations
(2021) Temba, G.P; Mauya, E.W; Shemwetta, D.T.K
Skidding operation constitute the entire process of moving felled trees from the stump site to the roadside landing. This operation normally bears substantial amount of the mill delivery costs. Thus, detailed information on productivity and cost is important for planning of cost-effective skidding operation. This study was conducted at Sao hill Forest plantation to quantify productivity and costs of tree length skidding operations. Continuous time study technique using snap-back method was used for time recording. Costs data were obtained from Mufindi Paper Mill logging department. Productivity and costs modeling, were performed using Microsoft excel. The analysis, showed that; the average productivity of the grapple skidder using tree length (TL) ranges between 398.423 m 3 /hr at a distance of 10 m and 49.862 m 3 /hr at a distance of 80 m. On the costs analysis, the unit skidding costs tends to increase with an increase of skidding distance (m) from 512.197 TZS/m 3 at a distance of 10 m to 4,092.675 TZS/m 3 at a distance of 80 m. Based on these findings it is recommended that variables distance and volume are the core factors to consider during planning to enhance efficient and costs effective skidding operation.
Optimal rotation age of pinus patula in government forest plantations in Tanzania
(Tanzania Journal of Forestry and Nature Conservation, 2021) Mugasha, W.A; Laswai, F.F; Malimbwi, R.E; Chamshama, S.A.O.; Abdallah, J.M; Mauya, E.W
A study to determine the optimal rotation age of Pinus patula was conducted in five forest plantations in Tanzania, i.e., Kawetire, Kiwira, North Kilimanjaro, West Kilimanjaro and Meru. Growth and yield, and mechanical properties data were collected from compartments representing age from 5 to 25 years. In addition, revenues and management costs data were collected for the purpose of determining the economic rotation age. For the purpose of determining the optimal rotation age based on growth and yield, the following basic models were developed: 1) site index curves model, 2) height-D model, 3) Single tree volume model, 4) Basal area growth model 5) stand volume model, 6) mortality model, and 7) simulation of thinning. Analysis of Variance (ANOVA) was carried out to ascertain whether the wood properties vary across age classes. Economic analysis of rotation age data involved computation of Net Present Value (NPV). Growth and yield data revealed irrespective of site class, P. patula can be harvested at age of 18 years while mechanical wood properties show that harvesting ages range between 16 and 21 years. Based on NPV, the optimal age was 16 years. Therefore, it is recommended P. patula be harvested at age of 18 years irrespective of site class.