Clarkys Comment - October

Tree Felling Observers

It is well known in forestry internationally that breaking out (hooking up tree stems to cables or chains for in-haul) and tree felling are tasks where injuries and deaths are more likely to occur. In New Zealand Safe Operating Procedures (SOPs) have been developed for both tasks, along with certification regimes. In addition there is a strong NZ forest industry drive to use grapples rather than humans for breaking out, and specialised felling heads on excavator or specialised felling machine bases for tree felling.

Breaking out is a safe operation if the SOP is followed. Quite simply if the breaker-out is standing in the proper place at the time of in-haul he/she will be safe. But manual tree felling is not so simple to manage. There are lots of decisions to make, precise cuts to be made and apart from the tree itself, always the opportunity for loose or dislodged tree parts to fall from above, along with some very tricky trees to fell.

It is these ‘falling objects’ that have our attention. Many readers will know that New Zealand updated its safety law during 2015 – the Health and Safety at Work Act (HSWA 2015). Alongside, we have also been issued a number of regulations, for example the General Risk and Workplace Management Regulations (GRWM 2016).

These Regulations list six ‘particular’ (critical) risks, which must be managed according to the prescribed hierarchy of controls. These particular risks include ‘remote or isolated work’ and ‘raised or falling objects’ and both can apply in tree felling. We have absolutely no choice but to manage tree felling with the best management controls available.

Not to be underestimated is the fact that tree felling is also a physically demanding task requiring full concentration. Humans don’t have enough eyes to see everything going on around both the base and the tops of the trees all at once. Should we be surprised that occasionally things go wrong!

So what are we doing in response to those particular risks?

The response to this risk has been to make a ‘person available to assist the tree feller’ – called a tree felling observer in New Zealand.

Tree felling observers have been compulsory for many years to assist in the management of an unplanned tree drive – where two or more trees need to be driven to the ground (ACOP for Safety and Health in Forest Operations 11.7.4). More recently, observers are seen as a practical response for all difficult trees and when felling in hazardous areas.

In an effort to avoid serious felling accidents in the future, PF Olsen has re-thought its response to tree felling risks. The big issue for us was understanding if there was any part of manual tree felling that was any less risky than any other part? In all honesty, highly qualified tree fellers were being hurt even in relatively innocuous settings where the circumstances left us scratching our heads! Others in the forestry industry have had similar experiences according to reports reviewed by us.

In view of that, we elected to start trialling full-time felling observers for all manual tree felling in March 2014.

Following feedback from tree fellers, contractors and supervisory staff after an 18-month trial period in the Central North Island the Company extended the policy to all its manual clear felling operations nationwide. In summary we have found:


  • Adds to daily crew cost and therefore increased harvest rate/tonne.

  • Puts an extra person in the danger zone.

  • Requires an additional qualified feller or trainee feller in the crew; possibly two to cover any absence of one of the fellers.


  • Having an observer assisting the tree feller in the 5 step tree falling process is improving decision-making and is resulting in a higher standard of tree felling.

  • Having an observer present full time is reducing tree feller exposure to the ‘7 harms’ see: Safe Manual Tree Felling from page 11.

  • Reduced fatigue. Observers and tree fellers rotate their position “tank for tank” (using up a tank of gas before swapping) i.e. two persons using one chainsaw sharing the felling and observer roles.

  • Much needed opportunity for training new fellers at no additional cost.

  • Families like it – “Someone is looking after my loved one.”. 

On balance we have determined that the positives outweigh the negatives.

Feedback received from fellers nationwide since the observer policy was implemented has been positive with the vast majority of fellers fully supporting the initiative. Different companies have tackled tree felling risks in different ways. It is good to see some conversations commencing that over time will pick up the best ideas and practices of all and have them promulgated in a revised ACOP. In the meantime, at PF Olsen at least, observers are here to stay. Of course machine felling is even safer. On-going developments in tethered machines working on steep slopes will open up more opportunities to use them wherever the terrain and contractor circumstances permit.