mgc in motion > papua new guinea > procedures


Procedure for Felling and Role of Trainer
Tree felling co-ordinator
- Reports to the Construction Manager
- Shall be an expert in the techniques used for felling trees of a similar type to those encountered in PNG and will be able to train all personel needed in all aspects of fellng Tropical Rainforest Trees

All activities related to this procedure
- Implementation of this procedure.
- Advising on techniques and safety precautions.
- Assisting with training of chainsaw operators.
- Ensuring that the safety officer are competent to mark out the work areas.
- Monitoring and assessing workers competency, including assigning grades to operators.
- Implementation of HSE rules and regulations applicable to the operations described in this procedure
- Shall ensure that the environmental pre-construction survey has been carried out and area in question has been approved for Tree felling.

The procedure was to be working with a 360 30 ton machine that had forestry specifications. This machine was to push over the smallest trees in the forest and to make the area safe. The felling crew were in front felling all medium and large trees and crosscutting them into 12 to 14 metres lengths for bridging materials. Then the machine followed pushing the small trees over and after them the cross cutters followed cross cutting any trees that the excavator had pushed over.

Excavator crossing a bridge. The bridge has been made out of trunks of 14 metres in length (See photo 30 tons of excavator crossing a water course, there was no bottom to this water very deep indeed) When the large trees were being felled only the trainer and the chainsaw operator were to be in close proximity to the tree. Often large Aluminium wedges were used on conventional felling cuts or leaning tree cuts were used on leaning trees. More often than not the medium sized trees needed the wedges and the large trees had a bias on them so leaning tree cuts were carried out.

See below left
This particular tree was hollow inside and leaning. A cut was made into the left buttress about 12 inches and the saw jammed solid. It was difficult to get out due to the compression but another saw and some wedges and eventually the bar came out. The little buttress to the side of the tree was also cut off. As soon as the little buttress was cut off noises were heard and escape was made very rapildly, where upon the tree fell over of its own accord. So no more than 14 inches of lateral wood had been cut off and the tree fell on its own. The tree had a minimum of 14 ft from buttress to buttress diameter. A certain percentage of the bigger trees were totally hollow which made them very dangerous to fell as they were so unpredictable. We would often carry out a test to see if they were hollow before we felled them.

Escape routes were paid particular attention to and cleared very carefully due to the numerous trip hazards that were found around the trees and the inherent behaviour of some of the trees. Most of the trees had large sometimes very large vines growing up them known as Lianas in S America these lianas are very dangerous as they can be connected to the next door tree or a number of trees sometimes numbering up to 7 or 8 when the tree is felled these lianas can pull whole trees over or the tops out of neighbouring trees causing much material to be falling over a very large area.

This can make the operation very dangerous. Escape routes sometimes have to be at least 10 metres plus sometimes due to the surrounding. area being covered in falling debris. Inevitably some trees are interconnected so felling cuts have to be put into the connected trees before the main tree is felled otherwise the main tree falling will cause the connected tree to snap and explode causing more danger to the faller so it’s safer to put in a half cut so when the large trees goes over it takes the smaller one with it safely. This practise in Europe is strictly prohibited and regarded as highly dangerous. Over in the rainforest it is necessary and needs to be done by highly skilled operators. If you cut to much then the smaller tree may fall onto you when you are felling the main tree. This will still kill you easily or seriously injure you.

There are a lot of different techniques that are necessary to make the felling operation safer. Holding the saws left handed sometimes is the only way to use them due to the height sometimes you have to cut at when you are felling the tree. We had no access to wrap around handles which are used in North America which make this practise safer and easier to use the saw.

Unfortunately accidents did happen to the equipment, this was the result of too much cutting into rotten hinge wood with a leaning tree The hinge wood collapsed onto the saw crushing it. The tree was rotten so very unstable and difficult to fell. (Nobody hurt in the process)surprisingly the saw looked badly damaged but was repaired and we used it the next day without a problem. Good old stihl saws they build them tough.

The whole area was limestone so sometimes very difficult to work in and due to the good drainage of the area you would sometimes come across sink holes well concealed under the foliage. These you could fall into which could again cause very serious injury. These could vary in size from a couple of metres deep to 5 km deep which a colleague told me he had worked in being lowered in by helicopter. I must say I would like to have seen that one.