21 June, 2021
Factors influencing productivity and cost in the whole-tree harvesting system
mechanized harvesting systems are the most productive and
common harvesting systems in the United States.
size, stand density, species composition, silvicultural
prescriptions, slope/terrain, and operator skill affect
the productivity and cost of a harvesting system. Timber
harvest expectations of foresters, landowners, and loggers
are dependent on these factors. A new article describes
the factors affecting the productivity of specific
harvesting machines used in whole-tree harvesting and its
impact on harvesting cost. The article summarises the main
factors which affect system productivity.
Size: Stem size is a significant factor that
affects the productivity of the feller-buncher.
Relatively large trees allow the machine to cut greater
volumes of wood per machine hour.
Distance: The efficiency of a skidder is greatly
affected by skidding distance because it strongly
affects the skidding time.
Density: The lower the stand density, the larger
the distance between harvested trees. The time spent on
driving to every single tree that is being harvested
increases when tree spacing is increased. However, the
larger volume of trees typically associated with a low
stand density can compensate for this decrease in
production and result in greater net productivity.
Composition: Pull-through delimber productivity
depends on the characteristics of tree species and
varies mostly with the hardwood content of a stand and
the thickness of branches. The productivity of the
pull-through delimber is lower in hardwood stands than
in softwood stands.
prescription: Silvicultural prescription
determines the type, quality, and quantity of wood to be
harvested and significantly affects the productivity of
harvesting operations. Generally, harvesting
productivity increases with higher removal intensity.
Steep slopes and uneven terrain negatively impact
harvesting productivity. Slope is an important
determinant of machine stability, impacting travel
speed, and duration of the work. Steep slopes also pose
considerable safety concerns for equipment operators. As
slope increases, the productivity of harvesting
The skill of the operator plays an important role in
determining the productivity of the harvesting
equipment. The difference in productivity is due to
different cutting techniques, work experiences, work
planning, felling order, and operators' dexterity. The
operator has some control over the average skid distance
and the size of payload per cycle which can impact the
productivity of the skidder. Operator skill in
combination with the machine and site condition affects
the efficiency of the grapple skidder and feller-buncher
by up to thirty percent. An operator also plays a vital
role in controlling stand damage caused by harvesting
authors were Parajuli, Manisha; Hiesl, Patrick; Smidt,
Mathew; Mitchell, Dana. The article was produced in 2020
and is titled "Factors influencing productivity and cost
in the whole-tree harvesting system".