Safety first in tree felling

Ruapehu Bulletin, Volume 9, Issue 428, 17 March 1992, Page 12

Safety first in tree felling

by trevor Hayes, bush inspector with theoccupational Safety and Health (OSH) section of the dept of labour (wanganui)

With the thought of winter approaching many people will be deciding to get their winter supply of wood in. It's this time of the year that concerns me as there's a high number of inexperienced people now Teaching for their saws. I see bad work practices being adopted by the average firewood cutter as a matter of course more commonly than not. This can be attributed to ignorance in most occasions. On average there has been a person killed each month since 1968 from injuries received while using a chainsaw, a number of these being in the non-commercial area, eg. farmers, firewood cutters etc., and with every fatality there is a high number of other serious injuries, which result in the persons concerned being incapacitated for considerable lengths of time. In the past two years two people have been killed in the OhakuneT aihape area through not following the correct procedures. The chainsaw is a marvellous piece of equipment but it can be lethal if it's used incorrectly. Even experienced bush workers can tell of near misses while using chainsaws which makes it even more important that the inexperi-

enced/casual chainsaw operator has an informed awareness of the right safety procedures, personal protective equipment and chainsaw maintenance before attempting to operate a saw. Buying your saw from a professional trader will ensure you get the right advice. Chainsaw injuries are especially serious because they don't cut, but chew or mince through flesh or bone. Foot, knee and thigh injuries to the left leg are the most common

general accidents. Upper body injuries can occur to the face, throat or shoulders when the saw has "kicked back" after hitting an obstacle. The saw shouldn't be used over shoulder height as

this severely reduces the control an operator has over the saw. When it comes to tree felling two types of accident are prevalent and they often end up as a fatality. One is when a dead branch or "sailor" is hooked up in a tree and falls when the tree is felled, the other is when a heavily leaning tree which has developed an enormous amount of tension splits or "slabs up". Willow, beach, tawa or macrocarpa are prone to split this way. Advice given in the booklet, "A guide to

Tree Felling and Cross Cutting", reflects the need for awareness of the dangers involved. You must wear a safety helmet, grade 4 ear muffs, safety legwear, snug fitting clothing and steel capped footwear whenever using a saw. The booklet gives the following general advice on tree felling: Before starting to fell a tree decide on the best position to start the scarf. Generally it should be with the trees prevailing lean, if any,

other persons in the vicinity. Before any felling cuts are started the following procedures MUST ALWAYS be adopted: • clear undergrowth adjacent to the tree to allow the free and safe use of tools and a quick, unobstructed path to safety. • inspect the tree to determine; weight distribution of the head and limbs; loose limbs, sailors, or other overhead materials; logs, saplings, or branches on the ground that could become a hazard; other trees or snags involved by contact when the tree being cut falls; the best escape route in the case of a mishap. • A sufficient scarf should be made in each tree being felled. Make sure that: The scarf is complete and cleaned out. Properly sawn the scarf will allow the tree to fall freely in the chosen direction. A clean uniform scarf must be used on all trees. The following guide should be used (see fig 1): • The top cut of the scarf should be made first at approximately a 45 degree angle. • The depth of the scarf should be one quarter to one third of the tree diameter.

• The two cuts which form the scarf must not cross at the point where they meet. Sufficient holding wood must always remain to maintain control of the tree so that it does not break, slip, or twist off the stump, and fall in any direction other than the intended. No matter how heavy the lean there are two main rules: • The back cut must be level and sawn rrTone tenth of the diameter of the tree ( and never less than 50mm) above the horizontal plane of the scarf to form an antikick back step. (see fig 2) • Always leave at least one tenth of the tree diameter as holding (hinge) wood, never cut all the way through a tree as loss of control will be the consequence. Equally the actual cutting up trimming of a tree is also extremely hazardous with the correct procedures needing to be adopted to prevent injury, these procedures are also described in detail in our felling booklet. For further information please contact Trevor Hayes at Occupational Safety and Health, PO Box .4151 Wanganui or phone (06) 345-3778.