Working Techniques for Thinning + tips

Trees intended for felling during thinning are not marked, because the decision is made by the operator during the work. It is he who, based on his experience in thinning, selects the trees that should be felled.

There are two thinning techniques – thinning with a harvester and thinning with a harvester and chain saw

Let’s start with the first one.

Tree limbing should be carried out over a previously prepared logging road. To protect the tree stand, branches should be dropped on the tree roots. If necessary, a harvester head can be used to spread the branches.

The next step is to choose a place to place the stack.

Trees should be cut over the road, and trunks should be placed on the opposite side. To limit boom maneuvers, trees should be felled once to the right side and once to the left side. The felling direction is chosen according to the wood classification, as the trunks are often too heavy to move. If possible, thinning should be started with pulpwood, as this will facilitate skidding. Felling smaller trees towards the trail at the limit of the boom’s reach is a good practice, except when branches are needed to cover the logging road. It is recommended to harvest the tree by species.

The second thinning technique, i.e. using a harvester and chainsaw, is carried out by the operator of the harvester and forwarder and the sawmill.

The advantage of this technique is the possibility of manual felling of large trees, and only then further processing with the use of a harvester. It is also a good solution when the terrain is sloping or when the logging roads are far apart. In addition, the team can exchange tasks, thanks to which each employee learns to work in a different position.

Thinning is started by the harvester operator, who prepares the logging road by cutting trees within the reach of the forest crane. The saw operator may not start working until the machine has moved to a safe distance. Trees should be felled at the right angle to the road, while avoiding felling trees in bunches, as this may contribute to increased damage, difficulties in lifting individual trees and breaking tops. After the felling with the chainsaw is completed, you can proceed to the processing of the felled trees and those not harvested with the harvester. When sawing trees into logs, turn the trunk with the head and make the initial cut in the right direction.

There is also a method of thinning between trail that can be used during the second felling. It allows the use of greater spacing between trails, because the harvester then moves around the stand.

Additional tips

1. An area covered with a large layer of undergrowth should be cleared to speed up felling and, above all, to reduce the risk of damage to the remaining trees.
2. When the logging area is located near another plot, it is the responsibility of the foreman to inform the operator whether there is a possibility to enter the neighboring plot. The foreman should check this at the planning stage when the timber storage location is being determined.
3. There are 3 aspects to consider when laying underlayments:

• distance from the forest
• space for a stack
• convenient access

1. To prevent damage to the ditch, fill it with pulpwood or other low-quality wood. However, after thinning, remember to clean it.
2. It is forbidden to fell trees into young stands or recently planted stands, on overhead power lines or telephone cables, etc.
3. Before starting thinning, it is worth marking a logging road, which may be helpful during evening/night work and when the ground turns out to be difficult and demanding. The trail should be about 4 m wide.