Wednesday, 9 December 2009

Tree Felling the Safe Way

Basic Felling

This is a short guide to the felling of trees in areas where there is a clear space of at least two tree lengths clearance in all directions and therefore there is no need for pulling aids to ensure that the tree does not drop onto other trees nearby.


Before commencing this task a risk assessment should be carried out and any operator must be appropriately trained in the use of the chainsaw and how to carry out the basic tasks, for more detailed information on this subject please see the article Using a Rear Handled Chainsaw published on 11th November 2009 on the Granite Workwear web site.

Included in this risk assessment should be the prevailing weather conditions, particularly high winds.

Make sure that all the correct tools are available, these may include a breaking bar, a range of sizes of alloy or plastic wedges, a sledgehammer and a hand winch complete with a handle, strops and a cable. Wherever possible plan to minimise any manual handling by the use of the appropriate tools.

It is also important to remember that felling a tree is a one man operation and to ensure that no other operator or machine is within two tree lengths. Survey the site to ensure that there are no underground or overhead services nearby, including electricity, telephone, sewerage, water or gas.

The felling operation

Inspect the tree thoroughly to ensure that there is no dead wood, insecure branches or noticeable signs of decay. Decide on the direction you want the tree to fall and make sure you have a suitable escape route with no obstructions.

Remove any debris from around the base of the tree, and also any obstructing vegetation that may impact on the operation taking particular care that the dispersal of the exhaust fumes from the chainsaw are not restricted.

Remove any low branches ensuring that that you are protected from kickback by keeping the guide bar out of line with your body, also it is useful to use the stem for protection, never use the saw above the height of your shoulders.

Make a sink cut to make a hinge this helps control the rate and direction of fall. A sink cut is a triangular shaped cut with a horizontal base and a 45° angle placed in the direction that you want the tree to fall, it should be the depth of a quarter of the diameter of the tree and the top and bottom cuts must meet exactly with no overcut to damage the strength of the hinge.

Start the felling cut at or very slightly above the level of the bottom sink cut, as you make the cut be careful of the tree moving and trapping the blade. The felling cut must leave a hinge of at least 25 mm at right angles to the direction of fall. If the blade does jam switch the chainsaw off and then pull gently to try and disengage it, if it cannot be freed then use appropriate tools to open the cut slightly.

It is important to remember that once the felling cut has been started then the tree must not be left, the felling must be completed.

Once the felling cut has been completed then use a breaking bar to to lever the tree over, always remember to keep your back straight and use your legs to lift, also keep both hands on the lever.

When the tree starts to fall immediately step back and to the side into your pr-planned escape route always be aware that the butt of tree may rebound as the tree falls.

After the tree has been safely felled you can then commence the snedding operation to remove the limbs that were too high to reach when the tree was standing.

Crown Breakdown

Breaking down the crown of a large tree can be very dangerous, you should always be ready for the tree rolling or for the branches springing back when cut.

To ensure the tree does not roll the use of a properly anchored winch is required. Ensure that you have a clear escape route at all times and plan the work sequence so that this is possible. Ensure that there are no bystanders in close proximity. Never work underneath any part of the felled tree, if it moves you will be crushed.

While working continually assess the tension in the branches, especially those that are in contact with the ground and thereby supporting the main stem.

Cut away the smaller branches first retaining the main supporting branches, again never work above shoulder height. When tackling the larger branches ensure that any debris from your previous cuts has been cleared from the ground to ensure you have a secure footing. Always keep assessing any potential movement of the tree.

If the branches are large cut them down gradually rather than going straight to the stem. Once you have cleared the branches to shoulder height, use the winch to roll the tree in a controlled manner to bring the remaining branches to a safe cutting height. When you have cleared all the branches and the tree is in a stable sate you can de-limb flush to the trunk.

The Granite Workwear Site offers a large range of PPE specifically for forestry work including clothing, footwear, head, eye and ear protection, along with a number of articles similar to this one, if you have any questions please do not hesitate to ask us.

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