%0 Articles
%T Comparison of productivity, cost and environmental impacts of two harvesting methods in Northern Iran: short-log vs. long-log
%A Mousavi Mirkala, Seyed Rostam
%D 2009
%J Dissertationes Forestales
%V 2009
%N 82
%R doi:10.14214/df.82
%U http://dissertationesforestales.fi/article/1864
%X An empirical time study was conducted, firstly, to evaluate the effect of log lengths on time consumption, productivity, and the cost of timber harvesting in Northern Iran and, secondly, to enable a search for better techniques and harvesting methods for the region. This study compared total harvested and damaged trees after logging operations that utilized two different methods: short-log and long-log. In the short-log method the maximum log length was 5.20 m and in the long-log method minimum log length was 7.80 m.
The performance of the Stihl chainsaw, Timber jack 450 C skidder, front-end loader Volvo 4500 BM, and truck Benz 2624 and 2628 was studied for both the short- and long-log methods. Post harvesting assessment of damage to the residual stand was compared along skid trail by conducting the transect method while random sample plots were chosen for the assessment of damage along winching strips.
The average productivity of felling was 11.6 trees/effective hour while the average unit cost of felling was US$ 1.2/tree. The average productivity of processing in both the short- and long-log method was 32.5 and 39.4 m3/effective hour, respectively. The average productivity of skidding was 10.8 and 11.11 m3/effective hour in the short- and long-log method, respectively. The average loading productivity was 29.9 and 38.0 m3/effective hour in the short- and long-log method, respectively. The average hauling productivity was 3.23 and 3.71 m3/effective hour, while the average hauling unit cost was 9.6 and US$ 8.3/m3 in the short- and long-log method, respectively. The average unloading productivity was 144.2 and 69.6 m3/effective hour in the short- and long-log method, respectively.
Overall, productivity of the long-log method was higher than that of the short-log method, and consequently unit cost of the long-log method was lower than short-log method by US$ 1.2/m3.
The results showed that along winching strips the percentage of damage to the residual stand was 32.2 and 37.7 %, while the damages along skid trails reached 25.7 and 34.9 % in the short- and long-log methods, respectively.
Based on the analysis made in this study of different work phases, the effect of log lengths on the time consumption and productivity in the skidding, loading, and long distance transportation were similar to the study performed in Iran. However, the effect of log lengths on the residual stand showed different results from the previous study done in Iran.
As a conclusion, the models and results provided in this study could, in general, help forest managers to better understand the influencing factors, especially log lengths, on the productivity and cost in different work phases. It can be used for reorganizing and planning of forest work in order to meet the economic and environmental concerns.