Problems

The following section details some of the problems that can occur when felling trees, and is included here as a warning not to attempt anything for which you have not received the correct training, or for which you are not sufficiently experienced. Felling is rarely straightforward, and the problems listed below will regularly be encountered when felling trees.

Broadleaved trees

• The weighting and lean of the tree must be assessed carefully. In comparison to conifers, most broadleaved trees have large crowns, which are often unevenly balanced, and in felling they are likely to get caught or deflected by neighbouring trees. When the tree hits the ground the butt end is likely to kick back more than conifers due to the large crown.
• Ash, elm, sweet chestnut and willow are particularly likely to twist or break off the stump, or to break up and shed limbs when being felled. Ash and sycamore may split during felling, causing a slab of trunk to spring back towards the feller. A chain or strong rope should be fixed around the trunk about 1.2m (4’) from the ground prior to felling.
• Extra equipment, and the training to use it, is needed when felling broadleaved trees. In addition to the saw, an axe, a sledge hammer and wedge, a breaking bar, rope, hand winch and cable may be required. Saws are more likely to jam in broadleaved trees and especially in coppiced trees, due to the uneven weight distribution and twisted grain.
• Broadleaved trees tend to have buttresses at the base, which should be removed before felling. This requires skilled use of the axe or chain saw.
• Directional felling may be difficult due to the size of the tree and its crown. The sink should be one third of the stem diameter to aid control.
• If directional felling is required, you may have to lop unbalanced or awkward limbs. This should only be done by properly trained and equipped personnel.

Leaning and weighted trees

Few trees are in perfect balance. Most have at least a slight lean or imbalance in the weight of the crown, all too often in a different direction from the one in which you want the tree to fall.

Ropes or winches will be needed to control the fall. These may also be necessary for easier trees if it is essential to fell them with great accuracy or where, because of the terrain or obstacles, you cannot make the sink and felling cuts in line with the required direction of fall.

1. Where the tree is leaning or heavily weighted in the direction of felling, a chain or rope will need to be fixed around it to limit splitting. Despite the chain, the tree is likely to split suddenly and fall.
2. Where the tree is leaning or heavily weighted against the direction of felling, progs, ropes or winches will be needed to counteract the lean and keep the tree from pinching the saw. Such work should only be undertaken by trained and competent persons.
3. Where felling is at an angle to the lean, the sink is cut as usual, but the felling cut is made so as to leave an uneven hinge. As the tree falls, it pivots on the thicker part of the hinge and swings around at an angle to the lean. It takes considerable skill and judgement to make the felling cut in this situation. A winch or rope may be needed to give added control.

Trees on slopes

Trees on slopes require extra care.

• Finding a safe stance for felling is more difficult, because of the slope and slippery ground.
• Felling downhill has increased risks because of the momentum gained by the falling tree.
• Where there is no appreciable lean or weighting, or where the tree leans into the slope, felling uphill is less risky. Although this leaves quite a high stump, and the tree may get hung up, this method is safer. The butt end of the tree may have to be shifted downhill to free it.
• The tree may ‘jump’ badly or break downslope when it hits the ground.
• Where it is not possible to fell uphill, felling across the slope is safer than felling downhill.

Dead or diseased trees

Dead trees are dangerous to fell because they may give way unexpectedly or shed limbs while you are cutting. Dead trees of some species, such as elm and beech, can be hard work to fell because the standing deadwood may become much tougher, making it necessary to rest and sharpen tools more often. Ropes and winches may be necessary to guide the fall.

Diseased trees may look normal on the outside, yet may have rotted a considerable distance up the stem or down from rotten limbs. This weakens the tree and makes it hazardous to fell.

Hanging trees

Hung-up or lodged trees can occur where the tree gets caught up in other trees while it is being felled or due to windblow. Note the following:

• Hung-up trees are dangerous and need dealing with as soon as possible by a suitably qualified person. If this is not possible, an exclusion zone of radius at least twice the length of the tree should be clearly marked with warning tape to keep people away.
• Don’t work immediately under a hung-up tree.
• Don’t climb under a hung-up tree to try and shake it free, or to attach a rope.
• Don’t try to fell the tree which is supporting the hung-up tree. The stresses and imbalances make this highly dangerous.
• Don’t fell another tree across the hung-up tree in an attempt to dislodge it.
• Beware of dead wood in both the hung-up tree and in surrounding trees, which might be dislodged as the tree falls.

Windblown trees

Hand tools are awkward, slow and dangerous to use on windblown trees, especially where you have to cut upwards from the bottom side of the stem. A chainsaw in the hands of a qualified operator is the tool for the job. A few general points are given below.

• Windblown trees are very hazardous because they may be under considerable tension and are frequently in an unstable position. It is vital to assess the stresses on the tree before beginning to cut.
• Trees may be partially or completely uprooted, or the trunks may be broken but still hung up. The precise cutting sequence will depend on the situation.
• In general, one side of the stem will be under tension and the opposite side will be under compression. Wood under tension may, however, be present on more than one surface of the stem at different points along it. Wherever the surface of the stem is under tension, that is the dangerous side. Cutting sequences must be designed to reduce tension progressively and gradually.
• Workers must always prepare an escape route and be ready for the unexpected.
• Large branches add to the weight of the wood under stress. See information under ‘Snedding’(below).
• Cutting close to the butt is least risky, as this is the area of least stress. The root plate should never be stood on while the trunk is cut, as it may suddenly give way as the trunk is severed.
• The first severing cut should be made in the wood under compression. The final cut should be made in the wood under tension. The final cut should be staggered at least 25mm (1”) closer to the root plate to minimise splitting of the stem.
  
• If there is side tension, the final cut should be made on the safe (compression) side.