Productivity and cost analysis of skidding machines
Productivity and cost analysis of skidding machines in forest
plantations in north of Iran
Department of Forestry, Natural Resources Faculty, University of Guilan, Iran, e mail- [email protected]
Caspian forest of Iran covers an area with 1,925,125 ha
extends throughout the south coast of Caspian Sea and
northern part of the country. It has high production capacity
due to humid temperate climate and suitable soil. Caspian
forests extend for 800 km in length and 110 km width.
These forest comprise a little more than 1.9 million
Small area of plantations and limited financial capacity
Table 1. Regression model developed from the detailed time study of log
prevent the use of special machines for harvesting,
skidding with forest machines in the study area.
therefore, forest companies use the same ground-based
Skidder Timberjack 450C
machines and equipment for wood extraction in plantation
Skidder HSM 904
area. Rubber-tired skidders such as Timberjack450C,
Farm tractor ITMCO 285
= 1.12 + .022
= 3.161 + 1.722 + 1.22 + .017
= 8.75 + .36 + .07
HSM-904, and farm tractors are the most commonly used
where: y – skidding time (min),n – number of logs per turn, d – skidding distance
logging machines in this area (fig 3).
(m),v – volume per turn (m3).
hectares of almost 100 percent hardwoods, primarily
Table 2. Unit costs of Skidder Timberjack 450C, Farm tractor ITMCO 285, and
beech (Fagus orientalis), hornbeam Carpinus betulus) and
oak (Quercus castanefolia) (fig 1).The small percentage of
softwoods include cypress (Cupresuss sempervirens),
juniper (Juniperus polycarpos), and yew (Taxus bacata).
About less than one million cubic meters of wood-based
products were legally generated from Caspian forests
Production cost ($)
annually. This amount allocated the small share of wood
consumption in Iran. As a result of limited production of
wood and high domestic demand in natural forest, exports
are essential. Of course, small part of this demand will be
provided by forest plantation in plain land.
Fig 3. Timberjack 450C (top left), Farm tractor (top right) , and HSM 904 (down)
during skidding in plantation are in north of Iran.
The aims of this study:
(1) Analysis of a continuous time study of logging
(2) Calculation of production rates and unit costs of the
Fig1. Natural forest in the mountainous area in north of Iran
There are several small patches of plantations which are
established by forest wood companies and forestry
Study area: Haftdaghanan plain in the Shafaroud forest,
Guilan province (Fig. 4). The study area covered 2,000
hectares of a 23-years-old plantation of the aspen
Populus del-toides, a poplar native to North America (Fig.
5).The trees were planted at a spacing of 4 × 3 m. The
average number of trees per hectare was 625 trees.
Fig. 6 Distribution of time consumption in log skidding with forest machines in
Currently, tree harvesting is done mostly in natural forests
and forests in mountainous conditions. In the last
decades, the forest company reforested many plain areas
for harvesting. Aspen and other fast-growing species
including coniferous species were planted, and currently
organizations. Due to the new forest policy in Iran aimed at
many of these plantations are ready for harvesting. For
decreasing the wood removal from natural forests, these
the first time, farm tractor, skidder Timberjack 450C and
plantations are a good resource in order to respond to the
HSM-904 were introduced in this plantation for log
high wood demand in the country.
Limited access to
natural forest resources has promoted the use of short
Overall, the farm tractor proved to have a high potential in
rotation woody crops by wood and paper companies in
skidding plantation area. It has been found that skidding
Iran as they are an important source of fiber and wood.
Fig. 5. Map of study area
distance and number of log are the most influencing
Species such as Aspen (Populous deltoides), loblolly pine
demonstrates that in small forest areas with small tree
Japanese- cedar (Cyrptomeria japonica) were used in
Method of study.
plain area for plantation (fig 2).
Work study technique based on IUFRO guideline was
used to calculate system hourly production. Based on
guideline of Forest, Range and Watershed Organization
(FRWO) of Iran, system hourly cost was calculated. The
elements of skidding work phase were identified and 30,
61 and 58 cycles for farm tractor, Timberjack and HSM
904 were recorded respectively. A linear regression model
was applied for finding the relation of dependent variable
(total time consumption) with appropriate independent
Fig 2. forest plantation with Populous deltoids (left) and Pinus taeda (right) in plain
area in north of Iran
diameters in a suitable terrain condition, farm tractors
work efficiently. Models introduced in this study can be
used in planning, work optimization, production and cost
estimation under similar working conditions to those
characteristics of each machines helps in choosing the
• Mousavi, S. R., & Nikooy, M. (2014). Evaluation of Tree Forwarding by Farm Tractor in
Patch Cutting of Poplar Plantations in Northern Iran. Small-scale Forestry, 13(4), 527540.
• Mousavi, R., Nikooy, M., Esmailinezhad, A., & Ershadfar, M. (2012). Evaluation of full
tree skidding by HSM-904 skidder in patch cutting of aspen plantation in Northern
Iran. Journal of Forest Science, 58(2), 79-87.
• Nikooy, M., Esmailnezhad, A., & Naghdi, R. (2013). Productivity and cost analysis of
skidding with Timberjack 450C in forest plantations in Shafaroud watershed, Iran. J.
FOR. SCI, 59(7), 261-266.