Chainsaw Safety Seminar Part Two

Advanced Techniques for Experienced People

Contents of Part Two. 
Wire Ropes Winching
Methods for different situations Tree Driving
Working in a Windthrow Bottom of Page

Barber ChairTrees with a heavy lean develop enormous tension on the upper side away from the lean.
Using conventional felling with a scarf and backcut can result in the tree splitting just after you start the backcut or as the backcut advances. The tree's splitting will form a "barber chair". You lose control and there's a risk of the tree sliding back into the work area.

 

  

Tawa and willow are two species that are notoriously liable to splitting. To overcome splitting, you can follow these steps:

  • Place the scarf in the normal manner.
  • Method overcome splitting
  • Make a bore cut, leaving a holding strap.
  • Make the back final cut as low as possible.
  • The amount of forward lean dictates the distance between the backcuts. The greater the lean, the greater the distance.

 

 

 

 

Certain standards must be maintained if trees are going to be back pulled by winches and wire ropes. Make sure' your equipment is checked on a regular basis and is adequate for the job in hand. here are some guidelines and advice:

Wire Ropes

  • Ropes must be of sufficient safe working load (SWL) to handle the job in hand.
  • Do not use knots in any wire rope.
  • Wire rope that is corroded, has signs of kinking or stranded wires or has been burnt should not be used.
  • Eye-to eye splices should not be used in any pulling rope. Joining with splices considerably reduces the rope's safe working load.

Equipment

  • Check that the blocks, shackles clamps, winches or any other equipment to be used is in first- class order -- your life could depend on it.
  • Only use 'D" shackles with secure pins. 'Do not use open- sided 'C' hooks. equipment used should have been tested and marked with the safe working load (SWL).
  • As a guide, any equipment used should be 1.5 times the SWL of the pulling rope.

Winching

Before any work begins, discuss fully with your colleagues what you intend to do. Winch and machinery operators must know what is required in relation to line tension and pulling speeds.

  • Work out your visual and vocal communication before you start the work.
  • Use sound stumps of sufficient size for the job in hand.
  • Strops used on stumps should be l.5 times the SWL of the pulling rope and should be notched in so they do not come off.
  • Machines used must have sufficient weight and winching power to control the tree to be felled. They should be equipped with a canopy that will protect the operator from roll over or falling objects.

In the Bight of an operating RopeBack Pulling- is the term used when pulling trees away from their natural lean. It is done to avoid trees damaging property or falling into an area in which they will be difficult to process, such as into a gully or over a bank.

  • Make sure all the equipment you need is on site.
  • Secure the rope as high as practicable on the tree. The higher the rope, the easier it will be to control the direction of the tree's fall.
  • Do not allow inexperienced people to do the felling. or to operate machines or winches.
  • Carefully read and follow the advice in the preceding "Winches and Wire Ropes" section.
  • Follow the felling techniques outlined in Section One. Do not take shortcuts or deviate from established felling methods.
  • Never allow people to work or stand ("in the bight" of an operating rope. ")In the bight of an operating rope.
  • Never allow machinery or people within two lengths of the trees being felled in case there's a mishap and the trees fall in other than the planned direction.

 


METHODS FOR DIFFERENT SITUATIONS

Let's look at methods suitable for different situations. The most common is a direct pull with the winch or machine further away than two tree lengths.
Pulling with winch

  • Scarf the tree in the normal manner but opposite the lean.
  • Tension the rope to hold the tree in position.
  • Backcut the tree in the normal manner, ensuring adequate hingewood is retained. Use wedges to hold the cut open if necessary.
  • Retire to a safe position and signal the pull to commence.
  • Pull slowly at first, then increase speed until the felling cuts take control.

 

If you cannot get two tree lengths clearance to the winch, there are two safe methods which you can use in more confined spaces.

The first method relies on the use of suitably located stumps. This method positions the winching equipment and operator in a safe position and allows good vocal and visual contact.

The layout required is shown below:

Suitably located stumpsFelling Procedure

The felling procedure is:

  • Scarf and start the backcut to the direction of pull in the normal manner, holding more wood away from the lean.
  • Begin the pull and continue the tension as the backcut continues and until the felling cuts take control.

The second method allows you to back pull the tree in the confined space without stumps being present. The layout is illustrated below:

Back pulling without stumpsDrive the machine out at about 80" opposite to the lean.

  • Tension the rope to hold tree in position of fall.
  • Scarf and backcut in the direction of the planned fall, holding more wood opposite the lean.
  • The tree will free fall, swinging on the rope with no danger to the operator or equipment.

 

 

Felling Procedure

 


TREE DRIVING

The term "driving" means pushing a tree over by felling another tree into it. Tree driving can be used in the following situations:
-- To take down a tree that has only partially fallen and is either lodged against or caught in the branches of another tree.
-- To drive a standing tree that has a slight back lean away from the desired direction of fall.
-- To drive a tree that has sat back on the cut.
-- To drive a tree into a more favourable position for processing.

Follow these steps for successful and trouble-free driving:

PREPARATION

  • Ensure people are well clear of the area. Remember the two-tree length clearance applies to both the driving tree and the tree to be driven.
  • The driving tree must be of sufficient size and weight to make the drive successful.
  • Don't make any cuts in the driving tree at this stage.
  • Choose a drive tree that has a good angle -- no more than 20' off the proposed direction of fall of the tree being driven.

TREES TO BE DRIVEN

  • Clear the escape route and your work area.
  • Scarf the tree to be driven in the normal manner. Take up the backcut, and at the earliest opportunity insert a wedge and drive it home as the cut proceeds. Stop the backcut so that sufficient wood is held to hold control of the tree.
  • If the tree to be driven is leaning and lodged in another tree, do not go under it or forward of it to see why it didn't fall to the ground.
  • Be aware of any debris, dead branches or material in either the driving tree and tree to be driven. This material may be thrown back into the work area at impact.

DRIVING TREE

  • Never use a dead tree as a drive tree or drive onto dead trees. On impact, pieces can fly in all directions.
  • Take extra care with the scarf and backcut of the driving tree as an indirect hit may result in the tree to be driven swaying back and falling into your work area, or pieces or branches breaking off and being thrown around.
  • As the driving tree falls, remove and shut off the saw, take the escape route and watch for any dislodged or flying material.
  • If you are driving a leaning or loaded tree, watch for the driving tree sliding down the leaning tree and kicking across into the work area.
  • If the drive is unsuccessful and trees are hung-up, mark off the area and get a machine to finish the work.

HAZARD WARNING
( Tree Sitting Back on Stump)

If you intend driving a tree that has sat back on the cut, or a tree that is "cut- up" (scarfed and backcut) and held by wedges, take extreme care. A small gust of wind can cause the tree to fall into the work area. Never turn your back on a cut-up tree.
Face the cut-up tree while making your scarf and backcut in the driving tree.

 


WORKING IN A WINDTHROW

Section one described how to deal with single windthrown trees. This part covers working in areas of windthrow.
In windthrow areas, normal hazards are multiplied by the presence of broken or shattered trees and varying degrees of tension due to the trees being interlocked, bent and partially fallen.
Approach each tree with caution. Examine the tree to see which way the tension lies
-- whether up, down or sideways
-- and determine the correct method of work.

 

  • Extreme care is necessary in dealing with bent or leaning trees. If there's a machine present, it can be used to uproot the tree and reduce the hazard. Otherwise, follow the guidelines given in this booklet for dealing with this situation.
  • Random lays with interlocking stems create special hazards because of bending and tensions caused by the interlocking. Carefully examine these and work out the sequence of cuts required to release the tension in a logical and safe manner.

Butting off a TreeWatch for rootplates springing back once the counterbalance of the tree is cut off. Use the cut illustrated below. Note the shift of cutting positions.

  • Always be aware of broken material that may move or be thrown around as you butt off trees or make cuts to logs under tension.
  • Many branches are under tension in windblown areas. Stand on the correct side, release the tension and then complete the cut.
  • When felling trees without tops, increase the scarf distance and insert a wedge as soon as possible to help guide the felling direction.