Third Edition 2015

Editors Simon Ackerman Duncan Fryer Roger Jackson Sally Upfold

Design and Layout Johan Pretorius, Beatrice Bosch and Sally Upfold

Photographic credits Unless otherwise stated, all illustrations and photographs used in this publication are with permission of Andreas Stihl (Pty) Ltd and Husqvarna South Africa (Pty) Ltd. © Forest Engineering Southern Africa and Institute for Commercial Forestry Research, 2015

ISBN 978-0-620-49065-8 All correspondence should be addressed to: The Director Institute for Commercial Forestry Research PO Box 100281, Scottsville, 3209, South Africa Telephone: +27 (33) 386 2314 Fax: +27 (33) 386 8905 Email: [email protected] World wide web: www.icfr.ukzn.ac.za

Indemnity The prescribed recommendations contained in the South African Chainsaw Safety and Operating Handbook are based on the current understanding of best operating procedures, and safety recommendations. FESA and the ICFR reserve the right to subsequently modify recommendations and no guarantees are provided, either explicitly or by implication. FESA and the ICFR must be acknowledged whenever information contained in this document is reproduced or used in any form.

A special thanks to our sponsors

ii South African Chainsaw Safety and Operating Handbook Table of Contents iii Table of Contents

Acknowledgements viii

Counterfeit chainsaws ix

Purpose of the handbook x

Chapter 1: Statutory requirements 1 1.1 General duties of employers 1 1.2 General duties of employees 2 1.3 Training institutions 2

Chapter 2: External components 3

Chapter 3: Health hazards 7 3.1 Exhaust fumes 7 3.2 The use of non-purpose ‘black oils’ 7 3.3 Vibration induced white finger disease (VWF) 7 3.4 Hearing loss 8 3.5 Musculo-skeletal injuries 8 3.6 Chainsaw inflicted injuries 8

Chapter 4: Personal protective equipment, other equipment and tools 11 4.1 Personal protective equipment 11 4.1.1 Safety helmets 11 4.1.2 Eye protection 12 4.1.3 Hearing protection 12 4.1.4 Gloves/mitts 14 4.1.5 Leg protection 14 4.1.6 Footwear 14 4.2 Other equipment and tools 14

Chapter 5: General safety requirements 17

Chapter 6: Transportation 19 6.1 Transporting a chainsaw by vehicle 19 6.2 Carrying a chainsaw 19

Chapter 7: Starting the chainsaw 21 7.1 Starting on the ground 21 7.2 Standing start 22

South African Chainsaw Safety and Operating Handbook iii Chapter 8: Reactive forces 23 8.1 Kickback 23 8.2 Pull-in 24 8.3 Pushback 25

Chapter 9: Cutting with the chainsaw 27 9.1 Holding the chainsaw and proper stance 27 9.2 Cutting actions 28 9.2.1 Down cut 28 9.2.2 Upcut 28 9.2.3 Bore/plunge cut 29

Chapter 10: Felling 31 10.1 Factors influencing felling productivity 31 10.2 Felling direction 31 10.3 Entering felling zones 32 10.4 Safety requirements during felling 32 10.5 Felling aids 33 10.5.1 Felling levers 33 10.5.2 Felling wedges 34 10.5.3 When to use wedges and felling levers 34 10.6 Felling and timber losses 34 10.6.1 Stump heights 34 10.6.2 Stem breakage 35 10.6.3 Tearing at the stump and splitting 35 10.7 Felling quality 35 10.8 Preparing for felling 36 10.8.1 General work area 36 10.8.2 Individual tree to be felled 36 10.8.3 Preparing the felling site 37 10.9 Felling position 38 10.9.1 Position when making the directional notch 38 10.9.2 Position when making the felling cut 40 10.10 Felling techniques 40 10.10.1 Standard felling technique 41 10.10.2 Specialised felling techniques 44 10.10.2.1 Large trees with a diameter more than the guide bar length 44 10.10.2.2 Large trees with a diameter double the guide bar length or more 44 10.10.2.3 Small trees that lean the opposite way to the felling direction 45 10.10.2.4 Trees that lean at a sharp angle towards the felling direction 45

iv South African Chainsaw Safety and Operating Handbook 10.10.2.5 Trees that lean away from the felling direction 46 10.10.2.6 Technique to reduce butt wastage 47 10.10.2.7 Trees that split 47 10.10.2.8 Stump cutting 48 10.10.3 Felling techniques using wedges 49 10.10.4 Consequences if cuts are not properly lined up 53 10.11 Hang-ups 54 10.11.1 Safety requirements for hang-ups 54 10.11.2 Methods of bringing down a hang-up 55 10.12 Machine assisted tree felling 57 10.12.1 Safety requirements 57 10.12.2 Methods for different situations 58 10.13 Sit back trees 61

Chapter 11: Debranching 63 11.1 Factors influencing productivity 63 11.2 Safety requirements 64 11.3 Working position 64 11.3.1 Working height 64 11.3.2 Working stance 65 11.4 Debranching quality 65 11.5 Debranching techniques 65 11.5.1 Lever/pendulum method 65 11.5.2 Debranching thick branches 67

Chapter 12: Cross-cutting 69 12.1 Factors influencing productivity 69 12.2 Safety requirements 69 12.3 Cross-cutting quality 70 12.4 Cross-cutting techniques 70 12.4.1 Tension on the upper side 70 12.4.2 Tension on the lower side 71 12.4.3 Lateral tension 71 12.4.4 Butting of aoot r plate 72

Chapter 13: Salvaging storm-damaged trees 75 13.1 Trees requiring special techniques 75 13.1.1 Uprooted trees 75 13.1.2 Stems or crowns broken but still attached 75 13.1.3 Leaning trees 76 13.1.4 Hang-ups 76 13.1.5 Trees without tops/crowns 76

South African Chainsaw Safety and Operating Handbook v Chapter 14: Cutting attachment 77 14.1 Saw chain 77 14.1.1 Component parts of saw chain 77 14.1.2 Chain dimensions 78 14.1.3 Cutters 79 14.1.4 Chip removal 81 14.1.5 Fitting of the saw chain on the saw 81 14.1.6 Chain tension 82 14.1.7 Running-in the saw chain 83 14.1.8 Chain lubrication 83 14.1.9 Sharpening 84 14.1.9.1 When to sharpen 84 14.1.9.2 Preparing saw chain for sharpening 85 14.1.9.3 Cutter sharpening terminology 85 14.1.9.4 Filing the chain 86 14.1.9.5 Sharpening errors 90 14.1.9.6 Replacing chain links 90 14.2 Guide bars 91 14.2.1 Guide bar design 91 14.2.2 Types of guide bars 92 14.2.3 Guide bar care 94 14.2.4 Guide bar maintenance 94 14.2.4.1 Dressing guide bar rails to remove burrs 94 14.2.4.2 Opening the groove 94 14.2.4.3 Replacing the sprocket 95 14.2.4.4 Replacing the replaceable nose 95 14.3 Chain drive sprocket 96 14.3.1 Construction and mechanical function 96 14.3.2 Types of chain drive sprockets 97 14.3.2.1 Spur sprocket 97 14.3.2.2 Rim sprocket 97 14.3.3 Sprocket wear 98

vi South African Chainsaw Safety and Operating Handbook Chapter 15: Chainsaw maintenance 99 15.1 Safety requirements 99 15.2 Refuelling 99 15.3 Maintenance 100 15.3.1 Pre-operational checks 100 15.3.2 Ongoing maintenance 101 15.3.3 Daily maintenance 101 15.3.4 Operation in burnt timber 102

Chapter 16: References and further reading 105

South African Chainsaw Safety and Operating Handbook vii Acknowledgements

The South African Chainsaw Safety and Operating Handbook is the result of a project initiated by Forest Engineering Southern Africa’s (FESA’s) Chainsaw Working Group. The project was made possible by the active involvement of various representatives of the forestry industry, chainsaw manufacturers and chainsaw users.

The following people contributed to the original Handbook (January 2000): Derek Howe (Co-author) DH Logging (Ex Nordfor) Guy Havemann Ex Nordfor Hilton Lane (Project leader) Husqvarna Koos Kotze SAFCOL Ian Conradie (Co-author) FESA Dave Hutton Stihl Dennis Ogram Nordfor Africa Roy Engelbrecht Mondi Jean-Pierre Poupard Sappi Nigel Fuller Husqvarna Deon van der Merwe Stihl Dylan Lane Husqvarna Rod Baker FG Licence

The following people contributed to the 3rd edition: Roger Jackson Husqvarna Duncan Fryer Stihl Dirk Längin Mondi John Eggers Mondi Andie Immelman Sappi Simon Ackerman FESA/ICFR

viii South African Chainsaw Safety and Operating Handbook Counterfeit chainsaws

The import of counterfeit chainsaws has increased recently. These products not only compromise the original products in terms of their trade mark, but fail to meet the standards of recognised industry safety and structural design qualities present in the original machines. It is important to note that: • Counterfeit is not just a copy; • Counterfeiting include ‘un-branded’ products intended for re-branding; • Counterfeits can at times include an element of fraud even if buyers are aware the product is fake; • Counterfeits lead to poor quality and a potentially hazardous product; • Counterfeits can lead to consumer distrust in a recognised brand; • An estimate of 3-7% of the value of world trade is counterfeit and is increasing; • Counterfeits damages legitimate businesses on all levels – in terms of brand owners, manufacturers, distributors and dealers in terms of loss of sales and loss of value in the brand.

South African Chainsaw Safety and Operating Handbook ix Purpose of the handbook

The “South African Chainsaw Safety and Operating Handbook” covers safety aspects, techniques and principles relating to the safe operation of a chainsaw, ensuring that the user understands the reason for certain mechanical and dynamic principles and reactive forces that exist. The Handbook is based on South African conditions, with the emphasis being on the chainsaw operator. The primary purpose of the Handbook is to make chainsaw operations more efficient and safer. A running chainsaw is ranked as one of the most dangerous power tools or pieces of equipment used in forestry. Unlike other saw types or moving machinery, the cutting mechanism of the chainsaw cannot be fully covered or protected due to the function it has to perform; namely felling, debranching or cross-cutting timber. The chainsaw is a highly engineered machine with a high torque engine and a high power to weight ratio. The operating speed of the chainsaw is in the vicinity of 12 000 to 14 000 rpm and has a chain speed in excess of 20 metres per second. These factors, combined with certain reactive forces, make it absolutely necessary for all chainsaw operators to be properly trained. The Handbook has been designed to standardise chainsaw handling requirements. It is therefore a convenient reference and guide to effective and safe working procedures. All chainsaw operators, instructors, training centres, tertiary education institutions, forestry company management, forest owners, maintenance facilitators and distributors should be fully aware of and conversant with the Handbook. All standards contained in the Handbook are internationally accepted and comply with those set out by the International Labour Organisation and the South African Occupational Health and Safety Act (Act 85 of 1993). As the Handbook is generic by nature, it does not replace the chainsaw owner’s manual, which is specific to a particular make and model of chainsaw. The Handbook underwrites all facets of FESA’s Guidelines for Forest Engineering Practices in South Africa, 1999, updated in 2014. With the establishment of the National Qualifications Framework (NQF) in South Africa, the Handbook is extensively referred to in the unit standards generated for chainsaw operators. It is therefore a useful tool for designing training courses and assessment guides and to compliment work and safety procedures for companies and institutions. Material presented in this handbook complies with the relevant unit standards.

Throughout this handbook general warnings will appear in red boxes,

WARNINIG:

Don’t stand directly behind the tree

and important points in green boxes.

IMPORTANT:

Begin the felling cut on the side that the tree is leaning towards

x South African Chainsaw Safety and Operating Handbook Chapter 1: Statutory requirements

1.1 General duties of employers According to the Occupational Health and Safety Act (Act 85 of 1993) Section 8, the general duties of employers to their employees are as follows: 1. Every employer shall provide and maintain, as far as is reasonably practical, a working environment that is safe and without risk to the health of his employees. 2. Without derogating from the generality of an employer’s duties under subsection (1), the matters to which those duties refer include in particular: a. The provision and maintenance of systems of work, plant and machinery that, as far as is reasonably practicable, are safe and without risks to health; b. Taking such steps as may be reasonably practicable to eliminate or mitigate any hazard to the safety or health of employees, before resorting to personal protective equipment; c. Making arrangements for ensuring, as far as is reasonably practicable, the safety and absence of risks to health in connection with the production, processing, use, handling, storage or transport of articles or substances; d. Establishing, as far as is reasonably practicable, what hazards to the health or safety of persons are attached to any work which is performed, any article or substance which is produced, processed, used, handled, stored or transported and any plant or machinery which is used in his business, and he shall, as far as is reasonably practicable, further establish what precautionary measures should be taken with respect to such work, article, substance, plant or machinery in order to protect the health and safety of persons, and he shall provide the necessary means to apply such precautionary measures; e. Providing such information, instructions, training and supervision as may be necessary to ensure, as far as is reasonably practicable, the health and safety at work of his employees; f. As far as is reasonably practicable, not permitting any employee to do any work or to produce, process, use, handle, store or transport any article or substance or to operate any plant or machinery, unless the precautionary measures contemplated in paragraphs (b) and (d), or any other precautionary measures which may be prescribed, have been taken; g. Taking all necessary measures to ensure that the requirements of this Act are complied with by every person in his employment or on premises under his control where plant or machinery is used; h. Enforcing such measures as may be necessary in the interest of health and safety; i. Ensuring that work is performed and that plant or machinery is used under the general supervision of a person trained to understand the hazards associated with it and who has the authority to ensure that precautionary measures taken by the employer are implemented; and j. Causing all employees to be informed regarding the scope of their authority as contemplated in Section 37(1) (b).

South African Chainsaw Safety and Operating Handbook 1 1.2 General duties of employees According to the Occupational Health and Safety Act (Act 85 of 1993) Section 14, the general duties of employees at work are as follows: 1. Take reasonable care for the health and safety of himself and of other persons who may be affected by his acts or omissions; 2. As regards any duty or requirement imposed on his employer or any other person by this Act, co-operate with such employer or person to enable that duty or requirement to be performed or complied with; 3. Carry out any lawful order given to him, and obey the health and safety rules and procedures laid down by his employer or by anyone authorised thereto by his employer, in the interest of health or safety; 4. If any situation which is unsafe or unhealthy comes to his attention, as soon as practicable report such situation to his employer or to his health and safety representative for his workplace or section thereof, as the case may be, who shall report it to the employer; and 5. If he is involved in any incident which may affect his health or which has caused an injury to himself, report such incident to his employer or to anyone authorised thereto by the employer, or to his health and safety representative, as soon as practicable but not later than the end of the particular shift during which the incident occurred, unless the circumstances were such that the reporting of the incident was not possible, in which case he shall report the incident as soon as practicable thereafter.

1.3 Training institutions It is recommended using certified training institutions that comply with industry standards and specific training criteria. It is important to check that institutions comply with industry and company specific requirements.

2 South African Chainsaw Safety and Operating Handbook Chapter 2: External components

In this Chapter, the main externally visible chainsaw components are identified and their functions briefly described. Some of the main components may be unique features of certain chainsaw models and makes. Important safety features and devices are noted in red (Figure 1). The internal components, mechanics and characteristics of the two-cycle chainsaw engine are not dealt with in this Handbook. Please refer to the owner’s manual or service agent for further information.

Figure 1: External components of a chainsaw

1. Cylinder cover and air filter 16. Chain catcher 2. Front handle 17. Clutch cover 3. Chain brake and front hand guard 18. Rear handle with right hand guard 4. Starter 19. Throttle trigger 5. Chain oil tank 20. Throttle lockout 6. Starter handle 21. Decompression valve 7. Combined start and stop switch 22. Oil pump adjustment screw 8. Rear handle 23. Chain tensioner 9. Fuel tank 24. Information and warning decal 10. Air purge 25. Product and serial number plate 11. Muffler 26. Combination spanner 12. Guide bar nose/tip/sprocket 27. Transport guard, chain and guidebar cover 13. Saw chain 28. Operators manual 14. Guide bar 29. Anti-vibration Rubber (no illustration) 15. Spike bumper

South African Chainsaw Safety and Operating Handbook 3 1. Cylinder/top cover and/or air filter cover The cylinder/top cover protects the operator from engine heat and noise, and assists with the cooling of the engine as chainsaws are air-cooled. The air filter cover protects and secures the air filter in position as well as reducing air induction noise. It could be part of the top cover or a separate cover. 2. Front handle The front handle is situated at the front of the chainsaw for the operator’s left hand. It is normally slightly angled and of the correct diameter to ensure a comfortable grip. 3. Chain brake lever/front hand guard The chain brake is designed to stop a moving saw chain in a split second, normally in the case of kickback. Kickback is the violent up- or sideward motion of the guide bar towards the operator (see section 8.1 for further information). The chain brake may be activated: • Manually, with the operator’s left hand or wrist pushing the chain brake lever forward. Some modern saws are equipped with an additional chain brake lever which is activated by the operators right hand; • Automatically, by an inertia process; • Some manufactures have a system where the brake is continually engaged and it is released when the operator grips the right handle. All chainsaws should be fitted with inertia activated chain brakes for safer operation. This function is especially useful when making horizontal felling or bore cuts or when debranching as the chain brake may not be activated manually by the operators arm. The front hand guard also protects the operator’s hand from injury that could be caused by branches and accidental contact with the saw chain should the operator’s hand slip off the front handle. 4. Starter cover The starter cover contains the starter mechanism and covers the flywheel and ignition module. The cover also has slots for important cooling air induction. 5. Chain lubricant tank and filler cap 6. Starter handle/grip To start the chainsaw the starter grip is pulled. 7. Combined stop switch or ignition on/off switch and choke control The stop switch must be accessible to the operator’s right hand thumb for emergency switch off. The choke is activated for cold starting. It may incorporate a start throttle lock which automatically locks the throttle control trigger in the correct position once the choke has been activated. 8. Rear handle The rear handle supports the operator’s right hand. It houses the throttle trigger and throttle lockout/palm lock. 9. Fuel tank and filler cap 10. Air Purge Air purge will improve the start ability of the saw which also reduces wear and tear on the starter. 11. Silencer/muffler The silencer reduces engine noise, directs exhaust emissions away from the operator and is normally fitted with a spark arrestor to reduce the risk of starting a fire. 12. Guide bar nose/tip/sprocket Most commercial operators choose guide bars fitted with a friction reducing nose sprocket. Other bars may have a solid nose.

4 South African Chainsaw Safety and Operating Handbook 13. Saw chain The saw chain performs the actual cutting. It is made up of different components. Refer to Chapter 14.1 for further details. 14. Guide bar The guide bar supports and guides the saw chain. Refer to Chapter 14.2 for further details. 15. Bumper spike/felling dog The bumper spike/felling dog is a toothed or smoothed stop for holding the chainsaw steady against the timber to be cut, thus facilitating ease of cutting. It also protects the muffler and chain lubricant tank. 16. Chain catcher The chain catcher reduces the risk of injury to the operator when the saw chain breaks or comes off the guide bar. 17. Clutch/sprocket cover The clutch/sprocket cover protects the clutch and chain drive sprocket. It also clamps the guide bar securely in place. The chain brake mechanism may be incorporated into the clutch/ sprocket cover. 18. Rear hand guard and handle The rear hand guard protects the operator’s right hand if the saw chain breaks or comes off the guide bar. 19. Throttle control trigger The throttle trigger is used to control the engine speed. 20. Throttle lockout/palm lock To prevent accidental acceleration, the throttle lockout must be depressed before the throttle control trigger can be activated. 21. Decompression valve The decompression valve reduces engine compression making for easier starting. It is not fitted on all chainsaw makes and models. 22. Oil pump adjustment screw To allow for constant lubrication and to prevent over oiling the oil flow to the bar and chain must be regulated depending on the length of cutting attachment used. 23. Chain tensioner The chain tensioner permits precise adjustment of the chain tension. The chain tensioner could be fitted in a different position on the chainsaw depending on the make and model, either in the front next to the guide bar or on the guide bar cover. 24. Information warning decal 25. Product serial number plate 26. Combination spanner/scrench The combination spanner/scrench is an essential tool for basic maintenance. 27. Transport guard/Chain and guide bar cover The chain and guide bar cover protects the saw chain and guide bar when the chainsaw is not in use and during transportation. It also prevents possible injury to persons whom may come into contact with an unprotected saw chain. 28. Manuals The manufacturer, operator and user manuals contain valuable user and safety information that must be studied.

South African Chainsaw Safety and Operating Handbook 5 29. Anti-vibration/vibration dampening system Most modern-day chainsaws have some form of anti-vibration system to lessen the effect of engine and cutting vibration to the operator’s hands. Normally the engine and cutting parts of the chainsaw is isolated from the handle, through vibration dampening elements such as rubber or spring mounts. Refer to Chapter 3.3 on vibration disease.

6 South African Chainsaw Safety and Operating Handbook Chapter 3: Health hazards

This chapter describes the major health hazards associated with chainsaw use. The operator must be aware of the following hazards:

3.1 Exhaust fumes Exhaust fumes contain carbon monoxide which can cause drowsiness and lack of concentration, thereby increasing the risk of an accident. The muffler has been designed to direct exhaust fumes away from the operator, thus reducing the risk. To minimise this hazard adhere to the following: • Maintain the muffler in good condition; • Ensure the chainsaw is properly tuned and maintained; • Do not work in confined and enclosed spaces.

3.2 The use of non-purpose ‘black oils’ The term ‘black oil’ comes from the use of discarded used engine oil as a saw chain lubricant. Not only does this material increase the ware and tare of the machine and its moving parts but is environmentally hazardous and toxic to the operator. The negative impact of the use of ‘black oil’ includes: • Blackening of the operators clothing and the accelerated perishing of this material in particular the safety clothing. This poses a risk to the safety of the operator; • Servicing of the machine is unpleasant due to the soot from the oil. The quality of the servicing may be reduced; • Used engine oil does not have the same viscosity for lubricating the chain. The carbon particles in the oil are also abrasive on the moving parts of the saw; • ‘Black oil’ is very damaging to the environment due to the additional chemicals added to the oil for engine use. This oil is also atomised by the operation of the machine into the air around the operator. This can adversely affect the operators’ health.

3.3 Vibration induced white finger disease (VWF) High frequency vibration transmitted from the chainsaw to the hand of the operator can affect the tactile sense of the hand and fingers. This phenomenon is known as VWF. It is caused by a reduced flow of blood to the finger extremities which is similar to the symptoms of Raynaud’s disease (Pyykkö et al, 1978). Excessive vibration can increase the likelihood of this disease, especially in cold climates. To minimise the risk of VWF adhere to the following: • Ensure the chainsaw is properly tuned and maintained; • Regularly check the effectiveness of the anti-vibration system; • Keep the depth gauge settings and chain sharpening to manufacturer’s specifications; • Wear gloves/mitts.

South African Chainsaw Safety and Operating Handbook 7 3.4 Hearing loss Noise louder than 85dB (A) can cause permanent hearing loss. The noise generated by chainsaws used in forestry applications far exceeds 85dB (A) and can therefore start to damage hearing after just a few minutes of use (Table 1). The damage caused by noise depends on the loudness and the length of exposure. Refer to Table 1 for noise levels to which a person can be exposed to per day without the likelihood of hearing damage.

Table 1: Maximum daily exposure to noise levels. (Occupational Safety and Health Service, 1995 & FESA, 1998.)

Noise Level Maximum daily exposure Description 85dB(A) 8 hrs Acceptable noise level 88 dB(A) 4 hrs Noise levels found inside open cab forestry 91 dB(A) 2 hrs equipment. 94 dB(A) 1 hrs 97 dB(A) 30 min Noise levels generally found in the proximity 100 dB(A) 15 min of high revving logging machinery. 103 dB(A) 8 min 106 dB(A) 4 min

109 dB(A) 2 min Levels to which operators of petrol driven 112 dB(A) 1 min chainsaws are exposed to. 115 dB(A) 20 sec

Operators and other people in the proximity of the working chainsaw (e.g. log scalers and felling assistants) shall not exceed the exposure time stated in the above table without wearing hearing protection. To minimise the risk of hearing loss adhere to the following: • All chainsaw operators and workers in their proximity must wear adequate hearing protection; • Ensure that a serviceable muffler, complying with the manufacturer’s specifications, is fitted; • Ensure the chainsaw is properly tuned, maintained and that all its components are fitted.

3.5 Musculo-skeletal injuries Musculo-skeletal injuries concern primarily the lower back, but the neck, shoulders, upper arms, hips and knees could also be affected. To minimise the risk of musculo-skeletal injuries, ergonomically established working methods and postures must be adhered to.

3.6 Chainsaw inflicted injuries Chainsaw inflicted injury statistics are recorded in various regions of the world and these injury trends are common to each other. Table 2 details injury trends in professional forestry applications in New Zealand between 1985 and 1991 (Parker, 1992). The table shows the probability of an injury occurring to a chainsaw operator on various parts of the body.

8 South African Chainsaw Safety and Operating Handbook Table 2: Chainsaw inflicted injuries statistics based on New Zealand operations between 1985 and 1991 (Parker, 1992)

Area cut by chainsaw % Head and neck 12.5 Torso 3.2 Arms and hands 39.9 Legs 20.7 Feet 22.3 Other 1.4 Total 100

It is important to note that operators were equipped with personal protective equipment and all chainsaws were fitted with safety devices. Other studies have found that most accidents occurred between 09:00am and 10:00am and within the first hour of work after a weekend break (ILO, 1991) and that adequate training can reduce accidents (Gaskin and Parker, 1993). To minimise the risk these of chainsaw inflicted injuries adhere to the following: • Follow the procedures in Chapter 8 relating to reactive forces; • Ensure that the chainsaw is serviceable and suitable for the task; • Use only recognised working methods and postures; • Use personal protective equipment as described in Chapter 4.1; • Comply with all safety standards referred to in this Handbook.

South African Chainsaw Safety and Operating Handbook 9 10 South African Chainsaw Safety and Operating Handbook Chapter 4: Personal protective equipment, other equipment and tools

Personal protective equipment and appropriate tools are essential to safe operation of chainsaws. It is important to adhere to the following aspects:

4.1 Personal protective equipment

WARNINIG:

Personal protective equipment may not always prevent all injuries but will minimise the effect thereof on the operator

Personal protective equipment (PPE) must be worn at all times whilst working with the chainsaw. According to Section 38 of the OHS Act (85 of 1993), the law specifies that the employer shall provide “adequate” protection, free of charge. Clothing must be sturdy and snug-fitting, but allow complete freedom of movement. Avoid using loose fitting clothing. It is advisable that operators wear highly visible shirts as this will assist in locating them. For institutions where chainsaw assistants are used, they are required to wear safety helmets, eye protection, hearing protection, leg protection and footwear complying with the same requirements as applicable to the chainsaw operator. When in doubt please refer back to the manufacturers and industry / company specific standards for the appropriate PPE. Chainsaw operators are required to wear the following personal protective equipment:

4.1.1 Safety helmets Safety helmets are designed to provide protection against falling objects. Adhere to the following: • Use only SABS (SANS 1397 standard) (EN 397 standard) approved safety helmets; • Replace safety helmets as per manufacturer’s instructions. (5 years after date of manufacture or 3 years after purchase). Figure 2 is read with the number in the centre being the year (2010) and the arrow pointing to the month of manufacture (February); • Do not modify safety helmets from their original design as it will reduce their strength (i.e. no stickers, permanent markers, cutting etc.); • Check suspension systems frequently; • Use safety helmets of a highly visible colour.

South African Chainsaw Safety and Operating Handbook 11 Figure 2: Manufacture date indication on hard hats

4.1.2 Eye protection Visors are designed to deflect or stop small particles such as wood chips. However, the visor will not completely prevent fine particles from penetrating the eye. Adhere to the following: • Use only EN 1731 standard approved visors; • Replace when damaged or as per manufacturer’s instructions; • Maintain and clean when required.

4.1.3 Hearing protection Hearing damage caused by exposure to continuous loud noise can be reduced by using hearing protection. Earmuffs or earplugs can be used. Earmuffs are preferred due to the fact that superior hearing protection is offered as well as increased comfort and better hygiene. Adhere to the following: • Use only hearing protection that reduces noise levels to below 85dB (A). It is recommended that hearing protection complying with EN352-3:1995 standard is used; • Clean and maintain according to manufacturer’s instructions; • Replace when damaged or as per manufacturer’s instructions; • Operator not to wear anything on head that does not allow the helmet to fit properly (Figure 3).

12 South African Chainsaw Safety and Operating Handbook A

B

C

Figure 3: (a) Improper use of headwear under helmet, (b) correct use of chainsaw headwear and (c) damaged earmuffs (Source: Gen James, 2013)

South African Chainsaw Safety and Operating Handbook 13 4.1.4 Gloves/mitts Protect hands with gloves/mitts when operating the chainsaw and handling the saw chain to avoid injury. Adhere to the following: • Replace when damaged or as per manufacturer’s instructions; • Use only gloves/mitts that are tight fitting allowing the chainsaw operator “good feel and grip” on the handles; • Gloves/mitts should preferably have a wrist strap to prevent sawdust from entering the glove; • It is preferable to use gloves/mitts that offer cut protection with chainsaw operation in mind.

4.1.5 Leg protection Use either chainsaw trousers or chaps that are held securely in place either with a suitable belt or braces. Leg protection is of utmost importance as the legs of a chainsaw operator are most susceptible to injury. Adhere to the following requirements: • Use only leg protectors complying with SABS (SANS 50381-5 standard) EN381-5:1995 standard; • Follow the cleaning instructions as per the manufacturer; • Replace leg protectors as per manufacturer’s instructions.

4.1.6 Footwear It is recommended to use footwear complying with EN ISO 20345:2004 standard. Or as an alternative use safety boots with adequate steel toe protection to provide protection against the running saw chain and rolling logs. These boots should be sturdy with steel mid-sole and non-slip soles that provide firm ankle support and an adequate level of cut resistance. Lace-up types must be securely fastened to prevent tripping over laces.

4.2 Other equipment and tools Chainsaw operators should be equipped with the following: • Round file and file holder /gauge; • Flat file; • Combination spanner or scrench; • Depth gauge tool; • A suitable container for fuel and chain lubricant. (Refer to Chapter 15.2); • Cloth/brush for cleaning the chainsaw; • Whistle to be carried to warn when tree is falling or for emergencies; • First aid bandage (number 5 bomb bandage).

14 South African Chainsaw Safety and Operating Handbook The following equipment and tools should be available on site: • Felling aids (either felling lever or wedges including a suitable tool for driving wedges); • Canthooks; • Lifting equipment (e.g. hooks, tongs); • First aid kit in close proximity; • Radio or mobile phone for emergency contacts; • Hand winch; • Fire extinguisher.

South African Chainsaw Safety and Operating Handbook 15 16 South African Chainsaw Safety and Operating Handbook Chapter 5: General safety requirements

Regardless of the type of operation (felling, debranching or cross-cutting) the chainsaw operator must adhere to the following general safety requirements: • Do not operate a chainsaw if not properly trained; • Trainee chainsaw operators may only operate under direct supervision of a competent person; • Do not attempt tasks not trained for; • Use only safe working methods and techniques as stipulated in this Handbook; • Follow all safety requirements as stipulated in this Handbook; • Use a professional chainsaw suitable for the task at hand; • Do not modify the chainsaw from its original design without the manufacturer’s permission; • Use a serviceable, properly maintained chainsaw; • Use chainsaws that are fitted with serviceable safety devices; • Wear the required personal protective equipment; • Do not operate a chainsaw in unsafe conditions (e.g. high winds, snow, heavy rain or poor visibility); • Do not work alone when operating a chainsaw, maintain contact with other workers at a safe distance; • Do not operate a chainsaw when fatigued or under the influence of drugs or alcohol; • Do not operate a chainsaw with one hand; • Do not operate a chainsaw above shoulder height; • Do not operate a chainsaw in trees or off a ladder if not trained and qualified to do so; • Do not cut any material other than timber; • Be aware of other workers and equipment in the proximity of the work area; • Never stand directly in front of a running chainsaw; • Ensure that the chainsaw is properly held, footing is stable and the correct working position is used; • Be aware of reactive forces (Refer to Chapter 8); • Be aware of slips and falls; • Be aware of public access roads or paths as cycling or other sports are popular.

South African Chainsaw Safety and Operating Handbook 17 18 South African Chainsaw Safety and Operating Handbook Chapter 6: Transportation

Ensure that the following guidelines are adhered to when transporting a chainsaw by vehicle or by hand in the compartment or between trees and cuts.

6.1 Transporting a chainsaw by vehicle Ensure that a chain and guide bar cover is fitted. Secure all loose tools, chainsaws and fuel containers in the vehicle so that they are not damaged in transit or cause discomfort or injury to people. Transport chainsaws, fuel and equipment separately from personnel.

6.2 Carrying a chainsaw When the chainsaw is not running and needs to be carried over longer distances, use any of the following methods: • Carry the chainsaw on the hip with the guide bar facing downwards (Figure 4); • Carry the chainsaw in the left hand with the guide bar facing backwards (Figure 5); • Carry the chainsaw in the right hand with the guide bar facing forwards (Figure 6). Ensure that the chain and guide bar cover is fitted. When the chainsaw is running and needs to be carried over shorter distances (e.g. walking from tree to tree in felling, debranching and cross-cutting operations), use any of the following methods: • Carry the chainsaw in front of the body with both hands firmly gripping the handles. The fingers must be off the throttle control trigger and the chain brake engaged. • Carry the chainsaw with the guide bar facing backwards and the chain brake engaged (Figure 5); • Carry the chainsaw with the guide bar facing forwards and the chain brake engaged (Figure 6); • As a general rule, when the operator moves his feet the chain brake should be engaged, except when the saw is on the opposite side of the log being debranched from the operator; • Ensure that the saw chain does not rotate (creep).

South African Chainsaw Safety and Operating Handbook 19 Figure 4: Carrying a chainsaw on the hip Figure 5: Carry a chainsaw with the guide bar pointing to the rear

Figure 6: Carry a chainsaw with the guide bar pointing to the front

20 South African Chainsaw Safety and Operating Handbook Chapter 7: Starting the chainsaw

The chainsaw operator must wear all personal protective equipment and ensure the saw is refuelled before starting the chainsaw.

7.1 Starting on the ground The chainsaw can be started on the ground, either in a standing (Figure 7) or kneeling position (Figure 8), using the following procedure: • Ensure the manufacturer’s instructions for starting the chainsaw are adhered to; • Remove the chain and guide bar cover; • Place the chainsaw firmly on the ground ensuring that the saw chain is unobstructed; • Hold the left arm straight, with the front handle firmly cradled between the thumb and fingers; • Place the front of the right foot in the rear handle; • Position the other leg to provide stability; • Ensure that the on/off switch is in the correct position; • Pull the starter grip with the right hand, using a short sharp pull. Allow the starter rope to retract under control.

Figure 7: Starting on the ground – standing Figure 8: Starting on the ground – kneeling

South African Chainsaw Safety and Operating Handbook 21 7.2 Standing start This method (Figure 9) is not recommended for starting large capacity chainsaws or chainsaws with long guide bars. Use the following procedure: • Ensure the manufacturer’s instructions for starting the chainsaw are adhered to; • Remove the chain and guide bar cover; • Place the left hand securely on the bend of the front handle (with the thumb under the handle). Keep the left arm straight; • Hold the chainsaw securely between the inner thighs with the guide bar pointing to the left of the body. Ensure that the saw chain is unobstructed; • Ensure that the on/off switch is in the correct position; Pull the starter grip with the right hand, using a short sharp pull. Allow the starter rope to retract under control.

Figure 9: Standing start

WARNING:

• Never drop-start a chainsaw. The chainsaw can swing in an arc at the end of the starter rope causing serious injury.

• Never start a chainsaw near fuel or other personnel.

• Never start a chainsaw without the guide bar, saw chain and clutch/sprocket cover fitted.

22 South African Chainsaw Safety and Operating Handbook Chapter 8: Reactive forces

Chainsaw operators must understand the major reactive forces that exist when cutting with a chainsaw as they can be the cause of accidents. The three reactive forces are kickback, pull-in and pushback.

8.1 Kickback Kickback occurs when the moving saw chain in the upper quadrant of the bar nose (kickback zone) contacts a solid object or is pinched (Figure 10). A rotational force on the chainsaw, in a direction opposite to the chain movement, is caused. This may kick the guide bar up and back or sideways in a sudden, uncontrolled arc. It is most common during debranching.

Figure 10: Kickback zone

Kickback may occur when the guide bar nose (Figure 11): • Is pinched unexpectedly; • Contacts solid material in the wood unintentionally; • Is used incorrectly to start a bore cut. (Refer to Chapter 9.2.3); • Hits hidden branches or light material; • Makes contact with the end of logs or obscured material.

Figure 11: Kickback situations

South African Chainsaw Safety and Operating Handbook 23 The greater the force of the kickback reaction, the more difficult it is for the operator to control the chainsaw. Factors that influence the occurrence and force of the kickback reaction include: • Saw chain speed; • The speed at which the guide bar and saw chain contact the object; • The angle of contact; • The condition of the saw chain. The type of guide bars and saw chain used is an important factor in the occurrence and force of the kickback reaction. Some guide bar and saw chain types are designed to reduce kickback forces, see manufacturers’ guidelines. Kickback can be minimised and the severity reduced if the following are adhered to: • Avoid cutting with the upper quadrant of the bar nose (Figure 10); • Hold the chainsaw firmly with both hands and maintain a secure grip; • Ensure that the left thumb is around and under the handle; • Be aware of the location of the guide bar nose at all times; • Avoid the nose of the guide bar making contact with any object. • Do not cut branches with the nose of the guide bar. Be especially careful when cutting small, tough branches, small size brush and saplings which may easily catch the chain; • Do not over-reach; • Do not cut above shoulder height; • Start the cut at high engine speed and maintain the speed as the cut proceeds; • Cut only one log at a time; • Use extreme caution when re-entering a previous cut; • Do not attempt to bore cut if not trained and experienced with this cutting technique; • Be alert for shifting of the log or other forces that may cause the cut to close and pinch the saw chain; • Maintain the saw chain properly. Cut with a correctly sharpened, properly tensioned saw chain at all times. Improper lowering or shaping of the depth gauges or sharpening of the cutters may increase the likelihood of kickback occurring; • Stand to the side of the cutting path of the chainsaw; • Ensure that a chain brake is fitted and serviceable; • Never operate a chainsaw without a serviceable chain break lever; • Use suitable guide bars and kickback reducing chains.

8.2 Pull-in The reactive force when cutting with the bottom of the saw chain tends to pull the chainsaw forward. This reactive force is increased when the saw chain on the bottom of the guide bar is suddenly stopped when it is pinched, caught or encounters foreign objects in the wood. This may cause the operator to lose control. It is also possible that the guide bar tip is pulled through the wood, exposing the tip and hitting another object causing a kickback. Pull-in frequently occurs when the chainsaw is not held securely against the tree or branch and when the chain is not rotating at full speed before it makes contact with the wood. Use extreme caution when cutting small sized brush and saplings.

24 South African Chainsaw Safety and Operating Handbook Pull-in can be minimised or avoided if the following are adhered to: • Ensure a correct stance with feet apart and firmly grounded; • Maintain saw chain properly. Cut with a correctly sharpened, properly tensioned saw chain at all times; • Hold the chainsaw firmly with both hands and maintain a secure grip. Ensure the left thumb is around and under the handle; • Always start a cut with the chain rotating at full speed; • Prevent pull-in by using wedges to keep the cut open; • Cut only one log at a time; • Be alert to forces or situations that may cause a pull-in situation.

8.3 Pushback The reactive force when cutting with the top of the saw chain tends to push the chainsaw backwards. This reactive force is increased when the saw chain suddenly stops when it is pinched, caught or encounters foreign objects in the wood. The reaction of the saw chain drives the chainsaw straight back towards the operator and may cause loss of control. Pushback can be minimised or avoided if the following are adhered to: • Ensure a correct stance with feet apart and firmly grounded; • Maintain saw chain properly. Cut with a correctly sharpened, properly tensioned saw chain; • Hold the chainsaw firmly with both hands and maintain a secure grip. Ensure the left thumb is around and under the handle; • Be alert to forces or situations that may cause a pushback situation; • Cut only one log at a time; • Do not twist the chainsaw when withdrawing the guide bar from bore cuts or cross-cuts as the saw chain may be pinched.

South African Chainsaw Safety and Operating Handbook 25 26 South African Chainsaw Safety and Operating Handbook Chapter 9: Cutting with the chainsaw

To ensure the safe operation of a chainsaw, the correct stance and handling of the machine should be adhered to at all times for different cutting actions.

9.1 Holding the chainsaw and proper stance The following general principles must be adhered to when making cuts; • Place the left hand on the front handle and ensure the handle is gripped between the thumb and fingers, with the thumb under the handle. The right hand should grip the rear handle, with the index finger on the throttle trigger; • Maintain control of the chainsaw while the motor is running by keeping a firm grip with both hands; • Keep the feet slightly apart but firmly grounded in a balanced position. Do not over-reach. Move feet closer to the cutting position if required; • Hold the chainsaw close to the body with the chainsaw body close to the cut for better control (Figure 12); • Bend the arms slightly to improve control of the saw; • Stand to the side of the intended cut to lessen the chance of injury from kickback; • Bend the knees or even rest on a knee when using the chainsaw in a low position, thereby keeping the back straight. This will reduce strain on the back.

Figure 12: Holding the chainsaw

South African Chainsaw Safety and Operating Handbook 27 9.2 Cutting actions

IMPORTANT:

Always cut at full throttle.

9.2.1 Down cut The bottom part of the saw chain and guide bar (pulling chain) is used in this cutting action (Figure 13). It is the safest and easiest cut as the chain action draws the chainsaw towards the cut and away from the operator. Sawdust will shoot backwards towards the operator.

Figure 13: Down cut using a pulling chain

9.2.2 Upcut The upper part of the saw chain and guide bar (pushing chain) is used in this cutting action (Figure 14). The chain’s reactive force will push the chainsaw away from the cut and towards the operator. Sawdust will shoot forwards away from the operator.

Figure 14: Upcut using a pushing chain

28 South African Chainsaw Safety and Operating Handbook 9.2.3 Bore/plunge cut

WARNING:

Making a bore cut can be dangerous if performed incorrectly because of the possibility of kickback. Only operators trained in this method should attempt this cut.

Start the bore cut by using the bottom portion of the nose of the guide bar and then the upper portion as the cut proceeds (Figure 15). Proceed as follows: Step 1. Using the lower tip of the guide bar, cut until the guide bar tip is completely buried in the wood; Step 2. Align the chainsaw towards the horizontal with the chainsaw at full throttle; Step 3. Still ta full throttle, press the guide bar straight into the log.

Step 1 Step 2

Step 3

Figure 15: Bore cut process

South African Chainsaw Safety and Operating Handbook 29 30 South African Chainsaw Safety and Operating Handbook Chapter 10: Felling

Efficient felling involves bringing down a tree in a safe, controlled manner, in the desired direction according to the operational plan, and complementing the extraction method to be utilised. Tree felling with chainsaws is the most dangerous operation in forestry. Safety therefore depends on the skill, experience, common sense and judgement of the operator. Consequently, emphasis must be placed on training, clear instruction, planning and supervision.

10.1 Factors influencing felling productivity Factors that influence productivity and product quality during felling operations include: • Tree diameter, length and volume (tree size); • Tree spacing (walking distance between trees); • Terrain (slope, ground roughness and ground conditions); • Tree species; • Stem form; • Crown shape and size; • Lean of tree; • Felling direction (uphill, downhill or parallel to the contour); • Density of regeneration and weeds; • Serviceability and suitability of equipment; • Operator skills; • Safety considerations; • Environmental considerations (riparian zones and other special management zones).

10.2 Felling direction Felling direction has a direct influence on extraction and other subsequent operations. Felling must be planned and controlled to facilitate extraction, reduce damage to remaining trees, keep harvesting activities away from special management zones and avoid loss of useful products (maximum value recovery). Felling direction will depend on: • Harvesting and transport system; • Extraction direction and method; • Assortments extracted (short length, long length, tree length or full tree); • Felling layout; • Slope; • Tree characteristics (lean, branchiness, crown type etc); • Obstacles in the felling path; • Weather conditions; • Safety considerations; • Environmental considerations (riparian zones and other special management zones); • Silvicultural requirements (slash management, re-establishment).

South African Chainsaw Safety and Operating Handbook 31 10.3 Entering felling zones The felling zone refers to the part of the stand where felling is taking place. All personnel must wear the required personal protective equipment before entering the felling zone. The following procedures must be adhered to: • Notify the supervisor or person in charge of the intention to enter the felling zone; • Exercise care while approaching any felling operation; • Draw the attention of the operator to your presence and intention of entering the felling zone; • Do not enter the felling zone until acknowledged or signalled to do so; • When exiting, exit via the route you entered. Do not cross over felling racks.

WARNING:

Remember to stay at least two tree lengths clear of trees being felled.

10.4 Safety requirements during felling All requirements in Chapter 5 apply. The following additional requirements must be adhered to by the chainsaw operator: • Fell according to the planned felling direction to facilitate subsequent activities; • Ensure that warning signs are posted; • Do not fell trees if any other persons, operators or equipment are within two tree lengths of the tree to be felled. This does not apply to chainsaw assistants/pushers who assist with felling; • In steep areas no other operation or person may be on the downhill side of the felling operation; • Where the danger exists that trees could fall onto public roads (e.g. felling on the upper slope) or when felling within two tree lengths from public roads, workers equipped with red flags must be placed on the road to facilitate safe traffic control; • Be aware of dead and dying trees as the directional felling of such trees is unpredictable; • Ensure sufficient fuel is in the chainsaw to complete all cuts on the tree being felled; • Complete the directional notch and felling cut, ensuring that the tree is on the ground before commencing to fell the next tree. Only single tree felling is permitted (no domino felling). Hang-ups and sit back trees must be dealt with as described in Chapters 10.12 and 10.13; • Do not complete the felling cut on the side towards which the tree is leaning; • Ensure the required felling aids are at hand and used if required; • Prepare for felling as described in Chapter 10.8. It is recommended that the chainsaw operator gives timely and adequate audible warning prior to completing the felling cut. Audible warning is not required if the operator has an un-obscured view of the entire area which could be affected by the tree being felled and is assured that there is no-one within the area.

32 South African Chainsaw Safety and Operating Handbook 10.5 Felling aids The primary purpose of felling aids is to: • Hold the tree upright; • Assist in directional felling; • Alter tree balance and weight distribution; • Keep saw cuts open and thus decrease the possibility of the guide bar being pinched. The main felling aids used in South Africa are felling levers and wedges. Felling wedges or levers provide lifting force to move a tree in a desired direction in proportion to its size and the lean of the tree. Graphically this relationship is described in Figure 16.

Figure 16: The lifting height of a wedge in relation to the DBH of the target tree in order to assist in felling a tree in a particular direction a maximum lean

10.5.1 Felling levers The felling lever (Figure 17) is commonly used when felling smaller trees in clearfelling but is vital in thinning operations. There are various models with varying handle lengths. When using felling levers: • Remove the bark where the felling lever will be inserted so as to ensure sufficient leverage; • Ensure that the felling lever is placed as deep as possible in the felling cut in order to achieve maximum leverage; • Lift with the legs, eepk the back straight. Refer to Chapter 10.10.3 for the technique using felling levers.

Figure 17: Felling levers and wedges

South African Chainsaw Safety and Operating Handbook 33 A felling lever with a hook can also be used as a canthook to roll trees or logs. It also has the added advantage that it can be used in taking down hang-ups. (Refer to Chapter 10.11).

10.5.2 Felling wedges Felling larger trees may require the use of wedges (Figure 17). Felling wedges can be made of different materials, e.g. wood, plastic, light metal or steel. Do not use steel wedges when felling small diameter trees as chain damage could occur. Steel wedges can be used on large trees as the probability of chain contact is less likely. Refer to Chapter 10.10.3 for techniques using wedges. Depending on the size of the tree to be felled, different sized wedges should be used. The wedge must be placed in the felling cut before it is completed.

10.5.3 When to use wedges and felling levers Felling wedges and levers are best used on tree sizes that they are designed for. Levers are best used on smaller trees while on larger trees wedges are more effective as they give more control to the chainsaw operator. Guidelines in the applications of wedges and levers are illustrated in Figure 18.

Figure 18: Guidelines for the use of felling wedges and levers used based on the tree size

10.6 Felling and timber losses Timber losses during harvesting can occur as a result of poor felling techniques.

10.6.1 Stump heights All trees must be felled as close to the ground as is practical without damaging the guide bar and saw chain. This is not always possible in the following instances: • When felling on steep slopes the angle of the ground will cause a higher than usual stump to occur; • When a tree is growing next to a rock or similar obstacle it may be difficult to fell such a tree without damaging the guide bar and saw chain; • Coppice stumps.

34 South African Chainsaw Safety and Operating Handbook 10.6.2 Stem breakage Stem breakage is a major cause of timber loss and occurs as a result of the tree falling in such a way that the stem breaks, splinters or develops cracks. Stem breakage will depend on the following: • Age of the tree – older trees are more brittle and more likely to break; • Species – some species are more prone to breakage than others; • Terrain – more breakage is expected on uneven terrain and terrain with many obstacles; • When felling over obstacles such as rocks, stumps, etc. the likelihood of breakage is high. Where trees are young and supple they can be felled on top of each other so as to provide more working height. This may not be possible as trees become older and more brittle; • When felling over depressions or humps, the weight distribution of the stem is placed unevenly on either the middle or ends, causing breakage in these areas; • When felling downhill on steep slopes the tree gathers momentum with every degree it travels through the felling arc. In the case of level ground it moves through 90° whereas on a downhill slope this is greater. The likelihood for breakage is thus greater on slopes and consideration should be given to felling parallel to the contour.

10.6.3 Tearing at the stump and splitting Tearing at the stump is normally caused by poor felling technique (Figure 19). Tearing at the stump and side splitting can be avoided by making side cuts on the stump. (Refer to Chapter 10.10.2.7).

Figure 19: Side split on stumps

10.7 Felling quality The following quality requirements must be adhered to: • Stump heights must be acceptable (Refer to Chapter 10.6.1); • Stem breakage must be minimised (Refer to Chapter 10.6.2); • Tearing at the stump and splitting must be minimised (Refer to Chapter 10.6.3); • Felling direction and layout must compliment subsequent operations; • Trim the butt end to log specification requirements; • Environmental and silvicultural requirements must be adhered to.

South African Chainsaw Safety and Operating Handbook 35 10.8 Preparing for felling The following should be considered when preparing for felling: • The general work area; • The individual tree to be felled. Before any felling commences the operator must ensure that all equipment is serviceable and suitable for the intended task and that all personal protective requirements are met.

10.8.1 General work area The general work area must be assessed for hazards as the OHS Act (Act 85 of 1993) places a responsibility on the operator to ensure his/her health and safety, and the safety of others. Felling also has an impact on subsequent operations. Therefore the operator must: • Determine the general felling direction, taking into consideration the tree characteristics, felling layout, terrain, extraction routes and landings according to the harvesting plan; • Ensure that there are no other persons or equipment within two tree lengths of the trees to be felled, unless these persons are acting as instructors or assistants; • Check for hazards such as electricity and telecommunication lines. Ensure that the necessary notification procedures are adhered to; • Check for hazards such as dead trees or trees that could affect felling; • If any road, railway or public access is within two tree lengths of the work area or could be at risk, ensure that the required notification and warning procedures are adhered to; • Check for other permanent structures within two tree lengths of the felling direction; • Check for special management zones that need special attention.

10.8.2 Individual tree to be felled Each tree to be felled must be assessed to ensure safety and to complement subsequent operations. Therefore the operator must: • Ensure that the felling direction is assessed (Refer to Chapter 10.2); • Plan to fell the tree so that it clears any obstructions and falls into a clear, open space, if practical; • Check for dead or broken branches/tops or debris that could fall into the work area when the tree is felled; • Check the lean of the tree; • Check for branches interlocking with other trees. These could break off as the tree falls and drop into the work area, pull the tree away from the desired felling direction, or cause other trees to uproot or fall; • Check for vines that could affect the felling direction; • Check for any rot where the felling cuts are to be made as this could affect the felling direction; • Have felling aids available, if required; • Ensure that the felling method is not affected by slope.

36 South African Chainsaw Safety and Operating Handbook 10.8.3 Preparing the felling site Once the general work area and the individual tree to be felled have been assessed, the operator must: • Remove all low branches that could hinder making the felling cuts. Work in a counter clockwise direction and cut using a pulling chain. Cut from the top to the bottom ensuring that the stem is kept between the operator and the chainsaw. Hold the chainsaw close to the body with the left foot in front of the right foot. Never work above shoulder height. The sequence of the operation is shown in Figure 20;

Figure 20: Removing lower branches

• Clear an adequate work area around the base of the tree and provide an escape route diagonally to the rear at approximately 135° from the felling direction. When clearing natural regenerated saplings, ensure that they are cut as low as possible sweeping the saw from left to right within the limitations of the operator’s stance and control. Be aware of kickback; • Always keep the escape route clear (Figure 21); • Identify any hazards such as stumps, logs or ground undulations that could cause the fallen tree to kick backwards or sideways on contact with the ground.

Figure 21: Escape route and clearing of obstructions

South African Chainsaw Safety and Operating Handbook 37 10.9 Felling position The position of the feller will depend on the size of the tree to be felled and the felling technique used. Refer to Chapter 10.10 for the terminology used in the following section.

10.9.1 Position when making the directional notch Stand behind the tree with the left shoulder resting firmly against the right-hand side of the tree. Place the left foot firmly behind you and the right foot forward in a balanced stance (Figure 22). See Chapter 10.10.1.

Figure 22: Lining up for the top cut of directional notch

Rest the chainsaw in front of the tree with the sight line on the chainsaw lined-up with the intended felling direction (Figure 23). Ensure that the chainsaw is securely lined up by using the sights on the chainsaw before proceeding with the top cut of the directional notch.

Figure 23: Lining up the chainsaw with the sight

38 South African Chainsaw Safety and Operating Handbook With larger trees it may be necessary to stand to the side of the tree when making the top cut. Lift the chainsaw into the exact position and proceed with the top cut of the directional notch at an angle of approximately 45° – 60°, cut to the required depth (Figure 24).

Figure 24: Felling position for top cut of directional notch

Remove the guide bar from the top cut and grip the front handle on the side, so that the guide bar is in the horizontal position. The trigger finger will revert from the index finger to the thumb. Keep the guide bar in the horizontal position and make the bottom cut. Keep looking down the top cut to gauge when the two cuts will meet (Figure 25).

Figure 25: Felling position for bottom cut of directional notch

South African Chainsaw Safety and Operating Handbook 39 With larger trees it might be necessary to stand to the side of the tree when making the bottom cut. The operator must bend sufficiently that the individual can see down the first cut (approximately 45° – 60°) so that it enables accuracy when removing the wedge without overshot. Remove the resultant wedge-shaped piece of wood once the bottom cut is completed. Note that, in this technique, the bottom cut always remains straight and does not slope to any one side.

10.9.2 Position when making the felling cut The felling cut for smaller trees is normally made whilst in the same position as for the top and bottom cuts of the directional notch. Beware of your legs when the chainsaw is brought around to the back of the tree to start with the felling cut, engage the chain brake between moves (Figure 26). Normally, with larger trees, it is necessary to stand to the side of the tree when making the felling cut, especially if the guide bar length is less than the tree diameter and specialised techniques are required (Refer to Chapter 10.10.2).

Figure 26: Felling position for felling cut

10.10 Felling techniques Once the preparation for felling has been completed, the operator is ready to make the first cut to fell the tree. Only felling techniques that have been assessed as being safe may be used. Techniques used will depend on the characteristics of the trees to be felled and the felling direction required.

40 South African Chainsaw Safety and Operating Handbook Modify the standard technique if the tree: • Have a one-sided crown or a significant lean; • Are leaning in a direction opposite to the desired felling direction; • Are leaning at a sharp angle towards the desired felling direction; • Have a diameter that is more than the effective length of the guide bar; • Are dead or have symptoms of rot; • Are prone to splitting. Use the appropriate specialised felling technique in these instances by adapting the depth of the notch, the shape of the hinge and by using felling aids.

10.10.1 Standard felling technique The standard felling technique (Figure 27) is used when the tree diameter is not more than the guide bar length and the tree has no significant lean.

Figure 27: Standard felling technique

Before commencing with the directional notch (this is applicable for other techniques and will not be stated again), reduce buttresses as required to achieve a more or less cylindrical tree-base to facilitate directional felling. If the tree has large buttresses (Figure 28), cut into the largest buttress vertically first, then horizontally and remove the resultant piece of wood.

South African Chainsaw Safety and Operating Handbook 41 Figure 28: Reducing a buttress

Directional notch The directional notch is important as it: • Controls the felling direction; • Allows the tree to fall freely in the desired direction; • Minimises splitting. The top cut is made first at approximately a 45° - 60° angle and for between ⅓ and ¼ of the tree’s diameter. The notch must accurately face the desired felling direction. The bottom cut must be made level to meet the top cut to form a clear, uniform “V” right across the diameter of the tree once the cut section is removed.

Hinge As the felling cut is brought towards the directional notch leave a sufficient hinge uncut 1 (approximately ∕10 of the tree’s diameter). The hinge (Figure 29): • Acts as a hinge and controls the felling direction; • Prevents the tree from twisting or bending sideways when falling; • Prevents the tree from falling backwards; • Controls the speed of the fall.

42 South African Chainsaw Safety and Operating Handbook Figure 29: The hinge

The felling cut The felling cut removes the wood from the back of the tree to leave the hinge and allows the tree to fall. The felling cut is made parallel to the bottom cut of the directional notch at either the same level or slightly above it (never below). If there is doubt as to the lean of a tree, insert a wedge in the cut as soon as practical and hit deeper as the cut proceeds.

1 The felling cut is taken up until there is an even amount of hingewood (about ∕10 of the tree’s diameter) left. The cut must never be taken up to or beyond the directional notch as the hinge will be eliminated and there will be no control over the direction of fall. Once the felling cut has been taken up and the tree begins to fall: • Remove the chainsaw from the cut; • Move into the planned escape route while watching the tree. Never stand directly behind the tree; • Keep watching the tree as it falls (never turn your back on a falling tree); • Watch for falling material; • Watch for the tree kicking back or bouncing as it hits the ground.

Once the tree is on the ground: • Ensure that it is stable; • Square the butt end, if required; • Reduce the stump height, if required.

South African Chainsaw Safety and Operating Handbook 43 10.10.2 Specialised felling techniques 10.10.2.1 Large trees with a diameter more than the guide bar length This technique is suitable where the tree diameter is up to double the guide bar length (Figure 30). Use the following procedure: Step 1. Make the directional notch as for the standard technique; Step 2. First insert the chainsaw, leading with the bottom edge of the guide bar to avoid kickback; Step 3. Continue the cut until the right hinge width is reached. Before making the swing part of the felling cut, saw back about the width of the guide bar. That way the hinge will not be severed; Step 4. Make the swing cut, being careful not to saw the hinge on the other side. If required, use felling aids before the felling cut is completed (Refer to Chapter 10.10.3).

Step 3 Step 2

Step

Step

Figure 30: Diameter up to double the guide bar length

10.10.2.2 Large trees with a diameter double the guide bar length or more This technique is suitable where the tree diameter is double the guide bar length or more (Figure 31). Use the following procedure: Step 1. Make the directional notch as for the standard technique; Step 2. Insert the chainsaw in the centre of the directional notch, leading with the bottom edge of the guide bar to avoid kickback; Step 3. Continue with the insert and swing cut as in 10.10.2.1 steps 2 to 4, ensuring that the hinge is thicker than normal to compensate for the insert cut. Use felling aids as required.

Step 3

Step 2

Step

Figure 31: Diameter double the guide bar length or more

44 South African Chainsaw Safety and Operating Handbook 10.10.2.3 Small trees that lean the opposite way to the felling direction Sometimes it is difficult to insert a felling lever when a small tree that leans opposite to the felling direction needs to be felled (Figure 32). This can be avoided using the following procedure: Step 1. Make the directional notch as for the standard technique; Step 2. Make one side of the felling cut in the normal manner and set the felling lever in the cut. The felling lever must be in line with the desired felling direction; Step 3. Make the final part of the felling cut tilting it down to avoid the felling lever. Ensure both felling cuts are slightly overlapped but still slightly above the joined directional notch.

Figure 32: Tree leaning opposite to the felling direction

10.10.2.4 Trees that lean at a sharp angle towards the felling direction If trees are felled which lean strongly with the felling direction, the danger exists that they will start to fall before the felling cut has been completed (Figure 33). This could result in the tree kicking back or the wood splitting. This can be avoided using the following procedure: Step 1. Make the directional notch as for the standard technique; Step 2. Cut a tunnel behind the hinge by boring the chainsaw straight through the tree. First saw up to the hinge. Then saw backwards, leaving a small heel in the felling cut. This heel will keep the tree from falling. Pull the chainsaw out of the tree; Step 3. Saw off the heel from the rear. Be ready to move out of the way of the tree quickly when it beings to fall.

South African Chainsaw Safety and Operating Handbook 45 WARNING:

Don’t stand directly behind the tree.

Step 2

Step

Step Step 3

Figure 33: Tree leaning at a sharp angle towards the felling direction

10.10.2.5 Trees that lean away from the felling direction This technique can be used to fell trees that lean obliquely away from the desired felling direction (Figure 34). Cutting an oversized directional notch on the side the tree is required to fall to causes the falling tree to be drawn that way. This method has its limitations and cannot compensate for major differences between the angle of lean and the desired felling direction.

IMPORTANT:

Begin the felling cut on the side that the tree is leaning towards.

Figure 34: Tree leaning away from the felling direction

46 South African Chainsaw Safety and Operating Handbook 10.10.2.6 Technique to reduce butt wastage To reduce butt wastage, a reverse directional notch can be made which results in the butt end of the log being cut square across (Figure 35). Ensure that the two cuts used to create the directional notch meet exactly.

Figure 35: Technique to reduce butt wastage (Humbolt technique)

10.10.2.7 Trees that split Under normal circumstances splitting can be minimised by making the directional notch as for the standard technique. Then cut “ears” (Figure 36) at each side of the stem at an angle of not less than 45°. These cuts must not exceed the guide bar width.

Figure 36: Technique to minimise splitting “Ears”

South African Chainsaw Safety and Operating Handbook 47 In veneer logs side splitting can be minimised by making the directional notch as for the standard technique. Then make side cuts (Figure 37) on the stump parallel to, and at the same level as the bottom cut of the directional notch, and no deeper than the guide bar width.

Figure 37: Side cuts to minimise veneer log splitting

10.10.2.8 Stump cutting Stump cutting has become a very important part of harvesting operations as the removal of stumps allows access to the compartment for extraction and silviculture machinery. This operation requires special care to be taken by the machine operator to reduce strain on the individuals back, and wear and tear on the chainsaw. When performing a stump cutting operations, it is important to: • Avoid operating alone, either have two operators or a supervisor present; • Ensure that the correct chainsaw and bar length for the size of the stumps are being used; • Prepare the stump and area around the stump correctly to ensure operator safety and to increase the lifespan of the equipment. Remove as much debris and sand on and around the stump as possible; • Be aware of sawdust and debris around the saw muffler as the heat generated by the muffler may be a fire danger; ▪▪ Make sure a spark arrestor is fitted and serviceable; ▪▪ Saw chain is sharp • Cutting with a wlo stance is: ▪▪ Ergonomically acceptable and with reduced risk of back strain and operator fatigue (Figure 38); ▪▪ Allows the operator has better control over his chainsaw. • When cutting large diameter stumps it is advisable to cut with one knee on the ground. ▪▪ This provide’s secure “anchor points” and therefore be a more stable stance as a reduction of injury risk;

48 South African Chainsaw Safety and Operating Handbook • Select the appropriate cutting action. A pushing chain or pulling chain can be used (Chapter 9.2) and the operator should be aware of the saw reactions when using either of these methods; • Choose the guide bar (solid or sprocket) that will suit the application and the economics of the operation (Chapter 14.2); • Make sure the chain is tensioned correctly for the bar; • Heavy duty filters should be fitted to the saw to prevent dust from entering saw; • Chain life can be increased by using a semi-chisel chain.

Figure 38: Stump cutting stances using low stance

10.10.3 Felling techniques using wedges

IMPORTANT:

It is recommended to use machine assistance for trees with a profound lean as wedges are limited in changing the felling direction (Refer to Chapter 10.12).

South African Chainsaw Safety and Operating Handbook 49 Wedges should be used in the following situations:

Felling large trees with no or slight lean This technique can be used where the diameter of the tree exceeds the guide bar length (Figure 39). The wedge will ensure that the desired felling direction is achieved. Use the following method: Step 1. Make the directional notch as for the standard technique; Step 2. Select the side of the tree from which the first part of the felling cut will be made. If the tree has a slight lean, or if there is rot or something in the crown that could dislodge as the tree falls, make the first part of the felling cut from that side by inserting the chainsaw, leading with the bottom edge of the guide bar to avoid kickback; Step 3. Continue the cut until the right hinge width is reached. Saw back about the width of the guide bar; Step 4. Continue with the first part of the felling cut. Place a wedge in the cut; Step 5. Saw the second part of the felling cut up to the hinge. Tap the wedge in as the cut proceeds. Always finish the second part of the felling cut on the safe side of the tree; Step 6. Drive the wedge deeper when the cut has been completed.

Figure 39: Felling large trees with no or slight lean

50 South African Chainsaw Safety and Operating Handbook Felling against the natural side lean of the tree To fell trees against the natural side lean opposite to the desired felling direction, the following method can be used (Figure 40): Step 1. Make the directional notch as for the standard technique; Step 2. Make the first part of the felling cut on the side of the tree it is leaning towards by inserting the chainsaw, leading with the bottom edge of the guide bar to avoid kickback; Step 3. Continue the cut until the right hinge width is reached. Leave a slightly narrower hinge than normal. Saw back about the width of the guide bar; Step 4. Continue with the first part of the felling cut. Place a wedge in the cut; Step 5. Saw the second part of the felling cut allowing for a wider hinge. Tap the wedge in as the cut proceeds. Always finish the second part of the felling cut on the safe side of the tree; Step 6. Drive the wedge deeper when the cut has been completed.

Figure 40: Felling against the natural side lean of the tree

South African Chainsaw Safety and Operating Handbook 51 Trees that lean back To fell trees that lean back from the desired felling direction (Figure 41 use the following procedure (remember that wedges are limited in changing the felling direction): Step 1. Make the directional notch as for the standard technique; Step 2. Make the felling cut as for the standard technique; Step 3. As soon as there is sufficient solid wood, insert the wedge or wedges in the cut and drive in as the cut progresses;

Figure 41: Felling trees that lean back

The split level felling cut method can also be used (Figure 42). This method is particularly effective on smaller trees as it allows the wedge to set when there is still a large amount of holding wood present. Use the following procedure: Step 1. Make the directional notch slightly shallower than normal; Step 2. Make one side of the felling cut in the normal manner and set the wedge in the cut. The wedge must be in line with the desired felling direction; Step 3. Make the final part of the felling cut tilting it down to avoid the wedge. Ensure both felling cuts are slightly overlapped but still slightly above the joined directional notch; Step 4. Keep the wedge driven up as the final cut is made. Use another wedge if necessary.

52 South African Chainsaw Safety and Operating Handbook Figure 42: Split level felling cuts

10.10.4 Consequences if cuts are not properly lined up Details are highlighted as follows (Figure 43 a - e): a. The bottom cut of the directional notch has been made too deep, leaving no hinge. The tree will fall without control and may cause butt tear from the centre of the butt log; b. The top and bottom cuts of the directional notch have been made to deep, leaving no hinge. The tree will fall without control; c. A felling cut overcut may result in the wrong felling direction and guide bar damage; d. A felling cut too far below the bottom cut of the directional notch reduces accuracy and control; e. A felling cut made too far above the bottom cut of the directional notch reduces accuracy and control.

South African Chainsaw Safety and Operating Handbook 53 Figure 43: Cuts not properly lined up (a) Bottom cut too deep; (b) Bottom and top cut too deep; (c) Felling cut over cut; (d) Felling cut too far below bottom cut; (e) Felling cut too far above bottom cut

10.11 Hang-ups A hang-up is a felled tree that is prevented from falling to the ground by lodging in another tree. Hang-ups are a potential fatal hazard and should be taken down immediately using an authorised method. If a machine is present it can be used to pull the tree to the ground. Otherwise, use a canthook, winch or levering device to dislodge the tree.

10.11.1 Safety requirements for hang-ups All requirements in Chapter 5 and Chapter 10.4 apply. The following additional requirements must be strictly adhered to: • Take hang-ups down immediately or, if that is not possible and someone is not present to warn others of the hazard; ▪▪ The risk zone under and around the hang-up must be clearly marked and all personnel must be kept out from the risk zone until the tree has been brought down safely. • Never move forward within two tree lengths of the intended direction of fall of a hang-up; • The following is prohibited: ▪▪ Work under the hung-up; ▪▪ Fell the holding tree; ▪▪ Climb the hang-up; ▪▪ Cutting lengths from the butt of the hang-up; ▪▪ Fell another tree onto the hang-up.

54 South African Chainsaw Safety and Operating Handbook 10.11.2 Methods of bringing down a hang-up Only recognised methods must be used to bring down a hang-up.

Rolling the hang-up Firstly, it must be decided which direction the tree can best be rolled free. Thereafter finish the felling cut and cut the hinge but always leave a small part on the side the hang-up will be rolled to. This in itself can sometimes cause the tree to roll free and become dislodged. The hang-up must be rolled away from the person performing the task, using a canthook or turning strap (Figure 44). Keep the back straight. If the tree is large or jammed hard against the other tree, a longer handle on the canthook or a turning strap can be used.

Figure 44: Rolling the hang-up

Levering or pulling the hang-up The hang-up can be levered away from the direction of lean using a sufficiently strong pole until the tree falls to the ground (Figure 45). The person performing the task must work on the safe side of the hang-up (the side the hang-up will not fall to once it is dislodged) whilst it is taken down.

Figure 45: Levering the hang-up

South African Chainsaw Safety and Operating Handbook 55 A hand winch attached to another tree can also be used to pull the hang-up until it falls to the ground (Figure 46). It is essential that a cable of sufficient length and strength is used. The person performing the task must work on the safe side of the hang-up whilst the hang-up is taken down.

Figure 46: Pulling the hang-up using a winch

Using a skidder or other mechanical winch When this type of assistance is available, it is the safest option (Figure 47). Once again, ensure that the cable is of sufficient length and strength.

Figure 47: Pulling the hang-up with a skidder

56 South African Chainsaw Safety and Operating Handbook 10.12 Machine assisted tree felling Machine assisted tree felling can be used: • To fell difficult trees into the desired direction; • To avoid damage to buildings, telephone lines, power lines, roads, railway lines and other structures; • To avoid environmental damage such as felling into streams, gullies, precipices or other special management zones; • To avoid trees falling into an area where they will be difficult to extract or process; • To salvage storm-damaged trees.

10.12.1 Safety requirements The following requirements must be strictly adhered to:

General safety requirements • Ensure that all the required equipment is on site, serviceable and suitable for the task; • Secure the cable as high as practical on the tree. The higher the rope, the easier it will be to control the direction of the fall; • Use only recognised methods of ascending trees as described in FESA’s “The South African Cable Yarding Safety and Operating Handbook, 1998” updated in 2015; • Allow only trained and experienced people to do the felling and to operate machines or winches; • Follow the felling techniques outlined in the Handbook. Do not take shortcuts or deviate from established felling methods; • Never allow people to work or stand “in the bight” of an operating cable (Figure 48).

Figure 48: “In the bight” of an operating cable

South African Chainsaw Safety and Operating Handbook 57 • Only use machine assistance that is capable of pulling the size of tree being felled; • Never allow machinery or people within two tree lengths of the trees being felled in case there is a mishap and the trees fall in another direction to that planned. Machinery is however allowed closer than two tree lengths if the methods in 10.12.2 are used; • It is recommended that an anchor cable is used in conjunction with the pulling cable. The anchor cable will ensure that the tree does not fall in the wrong direction.

Cable and equipment safety requirements • Check that cable are of sufficient safe working load (SWL) to handle the job in hand; • Do not use knots in any cable; • Do not use cable that is corroded, has signs of kinking or stranded wires or has been burnt; • Do not use eye-to-eye splices in any pulling cable. Joining with such splices considerably reduces the cable’s strength; • Check that blocks, shackles, clamps, winches and any other equipment to be used are serviceable; • Only use “D” shackles with secure pins. Do not use open-sided “C” hooks; • Use only equipment that has been tested and marked with the SWL; • As a guide, any equipment used should be 1.5 times the SWL of the pulling rope.

Winching safety requirements • Before any work begins, discuss with all people involved what is intended to be done. Winch and machinery operators must know what is required in relation to line tension and pulling speeds; • Work out visual and vocal communication before work starts. The chainsaw and machine operator must have an effective means of communication. This may require the use of an intermediate person in some circumstances; • Use sound stumps of sufficient size as anchors. Do not use standing trees as anchors; • Use strops of 1.5 times the SWL of the pulling cable; • Notch anchor stumps to ensure the pulling cable does not come off; • Use machines of sufficient weight and winching power to ensure that the tree to be felled can be controlled. The machine must be equipped with a canopy that will protect the operator from roll over and falling objects; • The chainsaw operator is responsible for the amount of tension applied on the tree.

10.12.2 Methods for different situations The various methods are described as follows.

Direct pull The most common is a direct pull with the winch or machine further than two tree lengths away (Figure 49): • Make the directional notch as for the standard felling technique; • Tension the rope to hold the tree in position;

58 South African Chainsaw Safety and Operating Handbook • Make the felling cut ensuring an adequate hinge is retained. Use wedges to hold the cut open if required; • Retire to a safe position and signal the pull to commence; • Pull slowly at first, then increase speed until the felling cuts take control.

Figure 49: Direct pull with winch or machine further than two tree lengths away

Indirect pull If two tree lengths clearance to the winch is not possible, there are two safe methods which can be used in more confined spaces. The first method relies on the use of suitably located stumps (Figure 50). This method allows for the safe positioning of the winching equipment and operator as well as good vocal and visual contact.

Figure 50: Method relying on the use of suitably located stumps

South African Chainsaw Safety and Operating Handbook 59 The felling procedure is as follows: • Make the directional notch as for the standard technique. Make the felling cut leaving more holding wood away from the lean (Figure 51).

• Begin the pull. Continue the tension as the felling cut continues, until the felling cut takes control; The second method allows for the felling of trees in confined spaces without stumps (Figure 52): • Drive the machine out at an angle of approximately 80° from the intended felling direction; • Tension the cable to hold the tree in the position of fall. • Make the directional notch as for the standard technique. Make the felling cut leaving more holding wood opposite the lean (Figure 53); • The tree will free fall, swinging on the cable with no danger to the operator or equipment.

Figure 51: Felling procedure with greater holding Figure 52: Method for back pulling the tree wood on the hinge away from the lean without stumps being present

Figure 53: Felling procedure for back pulling the tree without stumps being present

60 South African Chainsaw Safety and Operating Handbook 10.13 Sit back trees A sit back tree is where the tree sits back on the felling cut. It can result from misjudging the lean, failure to place a wedge in the felling cut, wrong felling technique or a gust of wind. Sit back trees should be taken down immediately or if that is not possible, and someone is not present to warn others of the hazard, the risk zone under and around the tree must be clearly marked and all personnel excluded from the risk zone until the tree has been brought down. Never move forward within two tree lengths of the sit back tree, except where the second lot of cuts are made as described below. The following methods can be used to bring down a sit back tree (Figure 54): • If a machine is present, it can assist to pull the tree in the desired direction with a cable; • Wedges can be inserted in the felling cut and hit until the tree falls; • If the felling cut is too tight for wedges to be inserted, remove the chainsaw from the cut or if that is not possible, remove the power head (if practical). Re-cut the directional notch and felling cut in the reverse direction, if in a safe felling direction. Make the second lot of cuts the diameter of the tree above the first cut as this will reduce the possibility of splitting. Insert wedges before there is any chance of the tree sitting back and keep them secure as the cut proceeds. Do not attempt to remove the chainsaw from the original cut whilst the second lot of cuts are made.

Figure 54: Method to bring down a sit back tree

South African Chainsaw Safety and Operating Handbook 61 62 South African Chainsaw Safety and Operating Handbook Chapter 11: Debranching

Debranching is the practice of removing branches and branch stubs from the stem (Figure 55). Starting from the butt end the branches are taken off flush with the stem up to the crown or end of utilisable timber. These branches are either left where they fall or stacked into heaps or rows. Debranching facilitates easier stacking, debarking, crosscutting and transport of timber.

Figure 55: Debranching a felled tree

11.1 Factors influencing productivity The major factors influencing productivity during debranching operations include: • Tree species; • Branchiness (size and number of branches); • Tree spacing (walking distance between felled trees); • Felling layout; • Felling direction (uphill, downhill or parallel to the contour); • Terrain (slope, ground roughness and ground conditions); • Serviceability and suitability of equipment; • Slash management requirements (scattered or in slash rows); • Operator skills.

South African Chainsaw Safety and Operating Handbook 63 11.2 Safety requirements All requirements in Chapter 5 apply. The following additional requirements must be adhered to: • Ensure that felled trees are stable before debranching commences; • Keep a safe distance of 3-5m between workers; • Where trees were felled parallel to the slope, first remove the lower branches but leave some supporting branches on the lower side, to ensure that most of the debranching can be done from the relative safety of the upper side; • Work on the uphill side of slopes, if practical; • Move the feet only when the chainsaw is on the opposite side of the stem and the saw chain is not running; • Keep both feet well away from the saw chain when debranching the far side of the tree; • Be aware of branches and undergrowth under tension and compression. Watch out for spring back; • Do not cut branches with the tip of the guide bar as it could cause kickback; • Do not allow the tip of the guide bar to make contact with uncut branches, supporting logs, butt-ends or other obstacles as it could cause kickback; • Maintain a firm grip on both handles of the chainsaw; • Do not reach across the guide bar in order to move loose branches; • In the case where the operator needs to take a hand off the saw, the operator must ensure that the stem is between the operator and the saw or that the chain brake is engaged; • Run the saw chain at full throttle before cutting starts and maintain a high saw chain speed throughout the cut; • When the saw chain is not cutting or the operator is moving, stop the saw chain against the stem; • Do not stand on the felled tree while debranching as the operator could slip or the stem may roll; • Take care if the felled tree is suspended by its branches as a large branch may hold the tree up. Cutting this branch can result in the tree rolling on top of the operator; • Do not cut branches behind your legs; • Be aware of safe distances from felling operations and people; • Be aware of moving equipment at the place of debranching.

11.3 Working position The operator should adopt an ergonomic working position to improve comfort, safety and reduces fatigue.

11.3.1 Working height Working height has two main objectives; one being the ease of operation and sustained endurance, the other being the exposure of all branches. If practical, work at a comfortable working height, and avoid working whilst bending over. This can be achieved by planning ahead and by correct felling. Use felled trees and the terrain to act as a working bench.

64 South African Chainsaw Safety and Operating Handbook 11.3.2 Working stance A stable work stance is imperative to ensure the safety of the operator (Figure 56): • Get a firm foothold and work with the chainsaw close to the body. Stand with the feet apart and do not over-reach; • Work with a straight back and bend the knees, when required; • Do not move the feet when branches are being cut; • Support the weight of the chainsaw on the tree or on the thigh; • Lead with the left leg.

Figure 56: The work stance for debranching

11.4 Debranching quality The product will influence the quality required. The following are applicable: • Remove branches up to the point of utilisable timber; • Debranch according to prescribed log specifications; • Comply with slash management prescriptions.

11.5 Debranching techniques 11.5.1 Lever/pendulum method In this method the chainsaw is used as a lever with the chainsaw body either resting against the stem or the operator’s leg as much as possible (Figure 57). This method is very useful for debranching trees with symmetrically placed branches. Pulling and pushing chains are used in debranching. Note the stance with the feet well apart. Rest the saw against the stem. Flex the knees. The same stance is used for all six steps of the debranching sequence.

South African Chainsaw Safety and Operating Handbook 65 Step 1. Branch 1 – far-side upwards Cut the branch from below using the top of the guide bar. The chainsaw under carriage is rested on top of the stem and moved through branch 1 as a pendulum using leverage. After cutting branch 1, lean the chainsaw against the stem.

Step 2. Branch 2 – top side across and towards the operator Pull the chainsaw across the stem with the guide bar resting on the stem. Cut using the top of the guide bar, leaning a little outwards with the legs and the right arm supported on the right leg. Beware of kickback.

Step 3. Branch 3 – nearside downwards Rest the rear handle against the right thigh. Cut the branch or branches on the nearside going downwards with the bottom of the guide bar. Let the chainsaw rest on and as close to the side of the stem as possible. Do not walk forward as the chainsaw is now on the operator’s side of the stem. Beware of kickback.

Step 4. Branch 4 – nearside upwards Move the chainsaw forward using the left knee or thigh, keeping the left foot in the same position. The chainsaw rests on that knee or thigh and the top of the guide bar is used to make the cut. Do not walk forward. Beware of kickback.

Step 5. Branch 5 – topside across and away from the operator Rest the chainsaw against the stem. Use the thumb on the throttle. Cut the branches on the top side using the top of the guide bar. Beware of kickback.

Step 6. Branch 6 – far side – downwards The chainsaw now slides down to the far side branches. Rest the chainsaw against the stem and cut with the bottom of the guide bar. Keep the guide bar on the opposite side of the stem whilst repositioning for the next sequence.

Repeat Steps 1 to 6 once more, if required. If the distance between branches is too great to follow steps 1 to 6, stop after step 3. Move the chainsaw to the far-side of the stem, move position and start the next sequence with branch 1.

Underside stem debranching Position left foot facing the tree and the right foot facing the thick end (the stump) and clear the branches from the underside of the stem. Support the saw by resting the arms against the knees/thighs. Sweep from left to right underneath the stem cutting the branches as flush as possible. Once the underside has been debranched, keep the chain pulling on the stem and sweep the guide bar over the stem with the chainsaw supported against the knee keeping the left arm in an extended position. Normally the underside is debranched after two debranching steps 1 to 6. Be alert for branches that may pinch the guide bar due to their weight or tension that has been put on them. These branches may first need to have the tension removed by an opposite cut before reverting back to the underside. If underside debranching cannot be done as part of the integral debranching sequence, turn the stem over (with a felling lever/canthook or other suitable tool) after the large branches have been cut and then complete debranching.

66 South African Chainsaw Safety and Operating Handbook Figure 57: The lever method for debranching

11.5.2 Debranching thick branches In some cases it can be difficult to use the lever method. This is often true with heavy, splayed branches. To avoid pinching the guide bar, cut the branches in stages starting from the outside. This results in the weight being removed before the heavy cut closest to the stem is made. The methods used for debranching thick branches are often quite similar to the cross-cutting method described in Chapter 12. Pinching and splitting can be minimised by debranching thick branches (Figure 58) in the following order: Step 1. Cut off branches which may hinder the operator by getting in the way; Step 2. Cut off branches with high internal stress. These branches are often cut in stages to relieve the tension.

South African Chainsaw Safety and Operating Handbook 67 Step 3. Finish off yb cross-cutting the main branch: • Use the right method; • Keep in mind that branches can be under considerable tension; • Keep the guide bar vertical to reduce the risk of pinching. If the branches are very large it may be necessary to make cuts from two different directions in order to avoid pinching and splitting.

Figure 58: Debranching thick branches

68 South African Chainsaw Safety and Operating Handbook Chapter 12: Cross-cutting

Cross-cutting is the practice of cutting a debranched stem into suitable log lengths. Cross-cutting can take place either infield, at the landing or at a merchandising yard.

12.1 Factors influencing productivity Factors that influence productivity include: • Tree species; • Tree size (diameter of logs); • Tree spacing (walking distance between felled trees); • Felling layout; • Felling direction (uphill, downhill or parallel to the contour); • State of conversion required (number of products); • Place of conversion (infield, landing, merchandising yard); • Terrain (slope, ground roughness and ground conditions); • Serviceability and suitability of equipment; • Operator skills.

12.2 Safety requirements All requirements in Chapter 5 apply. The following additional requirements must be adhered to: • Ensure that felled trees are stable before cross-cutting commences; • Keep a safe distance of 3-5m between workers; • Do not stand on the felled tree while cross-cutting as the operator may slip or the log may roll; • Do not work on the downhill side of the log being cross-cut. If unavoidable, logs must be blocked or otherwise secured to prevent rolling; • Be aware of rolling logs; • Cut only one log at a time; • Cut shattered wood very carefully as sharp slivers of wood may be caught and flung in the direction of the operator; • Do not cut with the tip of the guide bar as it ouldc cause kickback; • Do not allow the tip of the guide bar to make contact with branches, other logs or other obstacles as it could cause kickback; • Maintain a firm grip on both handles of the chainsaw; • Ensure a firm footing; • Run the saw chain at full throttle before cutting starts and maintain a high chain speed throughout the cut; • Use a wedge to keep the cut open if it seems likely that the guide bar will become pinched; • Be aware of logs under tension and compression; • Cross-cut logs under tension by making the first cut into the compression zone. (Refer to Chapter 12.4);

South African Chainsaw Safety and Operating Handbook 69 • Cross-cut from whichever side of the stem will not spring towards the operator when the log is severed; • Never attempt to cross-cut a tree or log that is in a dangerous position or if the cut cannot be completed; • Plan the work site to avoid cross-cutting close to moving equipment and other operations; • Keep a safe distance from felling operations and other people; • Be aware of people moving in front of the saw while cross cutting.

12.3 Cross-cutting quality The following are applicable: • Saw cuts must be made on the measured marks; • Saw cuts must be made in accordance with the log specification requirements; • Splitting on theaces f of logs due to incorrect cutting sequences must be minimised; • Presentation of timber must be in accordance with the operational requirements (stacked or non-stacked); • Do not nick trees or logs with the chainsaw.

12.4 Cross-cuttingechniques t In cross-cutting operations it is important to ascertain where the internal stresses are in the log. As a general rule for wood under tension: Step 1. The first cut is into the compression zone; Step 2. The second cut is into the tension zone.

12.4.1 Tension on the upper side The bottom of the log is under compression and the top under tension (Figure 59). The stem springs upwards. Use the following procedure: Step 1. Make a cut upwards for about ⅓ of the log diameter or until the cut begins to pinch the guide bar. Remove the guide bar with the saw chain at full speed. Step 2. Complete the cut from the top side with the two cuts meeting.

Figure 59: Tension on upper side

70 South African Chainsaw Safety and Operating Handbook 12.4.2 Tension on the lower side The top of the log is under compression and the bottom under tension (Figure 60). The stem springs downwards. Use the following procedure: Step 1. Make a cut downwards for about ⅓ of the log diameter or until the cut begins to pinch the guide bar. Remove the guide bar with the saw chain at full speed. Step 2. Complete the cut from the bottom side with the two cuts meeting.

Figure 60: Tension on lower side

12.4.3 Lateral tension Where the log is under lateral tension it is important for the operator to stand on the inside of the curve (the compression side) when cutting since the stem can easily snap outward after the cross-cut (Figure 61). As described previously, always start the cut on the compression side (the inside of the curve).

Figure 60: Lateral tension

South African Chainsaw Safety and Operating Handbook 71 12.4.4 Butting of a root plate Storm-damaged trees that have their root plates still attached require special treatment and cross cutting must be done under supervision (Figure 62). When cross-cut, the root plate can spring back to its original position and the log can move sideways towards the operator.

Figure 62: Butting of the root plate

Use the procedure in Figure 63 where the second cut is placed slightly beside the first one.

Figure 63: Procedure for butting of the root plate

72 South African Chainsaw Safety and Operating Handbook A similar situation can occur as sections are cut off the tree until the root plate counterbalances the tree and springs back into its original position (Figure 64).

Figure 64: Cutting of sections

Make every effort to put the root plate back in place once the stem has been severed, preferably using a machine or a winch to pull it back.

WARNING:

Never allow people to stand where they would be in danger of a root plate springing back on them.

Never cut trees that have the root plate still attached whilst standing on the stem.

Hints to reduce pinching Where there is danger of the saw being pinched by a falling log end, the following hints can be used (Figure 65): Hint 1. The cut is somewhat angled. Log falls down – saw is free. Hint 2. Cuts are made at a slight distance from each other. Log falls down – saw is free.

Figure 65: Hints to reduce pinching

South African Chainsaw Safety and Operating Handbook 73 74 South African Chainsaw Safety and Operating Handbook Chapter 13: Salvaging storm-damaged trees

In storm-damaged 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 or partially fallen. Approach each tree with caution and deal with them individually with careful planning and under supervision.

13.1 Trees requiring special techniques The following situations will require special attention: • Uprooted trees; • Stems or crowns broken but still attached; • Leaning trees; • Hang-ups; • Trees without tops/crowns.

13.1.1 Uprooted trees If uprooted trees are on top of one another begin with the top tree first. If possible, debranch the trees to increase visibility and reduce tension on the stems. Comply with the debranching requirements of Chapter 11 cross-cutting requirements of Chapter 12. Plan all cuts, escape routes and predict stem movement. Give special attention to the butting of root plates with the requirements of Chapter 12.4.4 adhered to.

13.1.2 Stems or crowns broken but still attached For partially broken trees, where the crown is resting on the ground but is still attached to the vertical stem, the following procedure must be used: • Cut away the crown tip, working in towards the upright stem up to shoulder height; • Use a canthook to twist the broken crown off. Always stand on the opposite side of the intended fall and never pull the broken crown towards yourself. Should this not work, the broken crown should be pulled with a hand winch or extraction machine; • If it is still firmly attached, the felling sequence is: ▪▪ Cut the crown off where it rests on the ground; ▪▪ Fell the standing part of the stem at a right angle to the crown direction using felling aids or a winch. Crowns broken but still attached and not touching the ground pose a further threat and should not be attempted unless under supervision.

South African Chainsaw Safety and Operating Handbook 75 13.1.3 Leaning trees Trees that lean due to storm-damage should be handled in the following manner: • Do not attempt to change the felling direction. Use the felling method in Chapter 10.10.2.4 (trees that lean at a sharp angle towards the felling direction); • Machine assistance can also be used if available. Comply with the requirements of Chapter 10.12.

13.1.4 Hang-ups Comply with the requirements of Chapter 10.11.

13.1.5 Trees without tops/crowns Fell the trees using the technique in Chapter 10.10.2.3 (trees that lean back).

76 South African Chainsaw Safety and Operating Handbook Chapter 14: Cutting attachment

The cutting attachment consists of the saw chain, guide bar and chain drive sprocket. Production results influenced by the cutting attachment depend on the following factors: • Selection of the orrectc chainsaw, including the cutting attachment, for the task; • Condition and maintenance of the cutting attachment. The saw chain is the component which does the actual cutting and could have the greatest influence on the results achieved. It is essential for the chainsaw operator, supervisor and manager to have a sound understanding of the cutting attachment. Correct use, maintenance and repair of the cutting attachment is of critical importance and if not correct, will have a negative effect on productivity, running costs, the life of the chainsaw and operator endurance. This Chapter of the Handbook is a guide to assist with the correct cutting attachment selection for a specific application as well as the correct use and maintenance thereof. Troubleshooting on the cutting attachment has not been included in this Handbook. Please refer to the manufacturer’s manuals for details.

14.1 Saw chain Saw chain manufacturers offer the correct saw chain for all cutting applications, chainsaw makes and engine capacities. The saw chain must be maintained according to the manufacturer’s specifications to ensure safe, productive and accurate cutting. A poorly maintained saw chain is dangerous to use and will reduce the life of the saw chain, guide bar as well as the engine.

14.1.1 Component parts of saw chain Saw chains are three-link chains, which are assembled in the same basic pattern (Figure 66). They normally differ only in the shape and size of the cutters and the individual links. The centre row of the saw chain is made up entirely of identical drive links. Engine power is transmitted via the chain drive sprocket to the drive link tangs causing the chain to rotate around the guide bar. The drive link tangs run in the guide bar groove and stabilise the chain in the lateral direction. The forward edge of the drive link tang is a rounded hook that acts as a groove raker/cleaner and a chain lubricant scoop.

1. Drive link and drive link tangs; 2. Tie straps; 3. Cutters; 4. Rivets; 5. Reduced kickback safety link (not standard with all saw chains). Figure 66: Component parts of saw chain

South African Chainsaw Safety and Operating Handbook 77 The two outer rows of links are made up of alternating cutters and tie straps. The cutters are the actual working parts of the chain. The design and condition of their cutting edges have a significant influence on cutting results. Tie straps are fitted opposite the cutters on both sides of the chain to fill the gaps between the cutters. They have the same basic bottom contour as the cutters and the two together form a sliding face on which the chain glides along the guide bar. All chain links are held together by rivets. To reduce kickback the normal tie strap in front of the cutter can be replaced with safetya link that has a higher profile than the normal tie strap or with a special three-humped bumper link. Specially shaped cutters and drive links can also reduce kickback (Figure 67).

Figure 67: (a) Normal tie strap; (b) safety link with higher profile; (c) three-humped safety link

14.1.2 Chain dimensions Chain dimensions include the following: • The chain pitch assigns the chain to certain models. It is calculated by measuring the distance between 3 rivets [a] and dividing by 2. The chain drive sprocket must have the same pitch as the chain (Figure 68).

a Figure 68: Chain pitch ( ∕2)

78 South African Chainsaw Safety and Operating Handbook • The chain gauge is the portion of the drive link that fits into the groove of the guide bar and matches the width of the guide bar groove. (Figure 69).

Figure 69: Chain gauge

• The chain length is determined by the length of the guide bar and is specified as a given number of drive links.

14.1.3 Cutters Parts of a cutter The parts of a cutter are illustrated in Figure 70. Thecutting edges are on the front faces of the top plate and side plate, i.e. the side plate cutting edge is vertical while the top plate cutting edge is horizontal and slopes to the rear. The front bottom part of the cutter is thetoe and the rear bottom part is the heel. The rivets which hold the chain links together pass through the rivet holes.

1. Top plate 2. Side plate 3. Depth gauge 4. Toe 5. Heel 6. Rivet hole

Figure 70: Parts of a cutter

The depth gauge is the small projection just in front of the top plate cutting edge. The top plate is inclined to the rear to form the top plate slope (Figure 71) and is the angle measure of this incline.

South African Chainsaw Safety and Operating Handbook 79 Figure 71: Top plate slope

The top plate is also tapered to the rear, forming the clearance angle for the side plate cutting edge (Figure 72).

Figure 72: Clearance angle

The top plate slope and the clearance angle help to reduce friction as they ensure that only the cutting edges are in contact with the timber to be cut. This is the measured as the tapered angle change from the cutting edge to the back of the top plate.

Cutter profiles Saw chain is described according to the shape of the cutters (Figure 73 a - c). • Chipper chain has rounded cutters. It is not normally used in professional forestry applications. • Semi-chisel chain has slim, slightly rounded cutters. It is suited to cut extremely hard and frozen timber as it reduces vibration that occurs in such conditions. • Full chisel chain is a fast-cutting, aggressive chain. The razor-edged, square shape of the cutters is ideally suited for South African commercial timber species. It meets the highest performance requirements of professional users in forestry.

(a) (b) (c) Figure 73: (a) chipper, (b) semi-chisel, (c) full chisel

80 South African Chainsaw Safety and Operating Handbook 14.1.4 Chip removal The following describes the chip removal process of a single cutter: When slight downward pressure is applied to the chainsaw (the dead-weight of the chainsaw alone is sufficient if the saw chain is correctly sharpened) the force transmitted pushes the top plate cutting edge into the bottom of the cut. The working corner and side plate cut the wood across the grain separating the chip from the side of the cut (Figure 74).

Figure 74: Chip removal cutting action

As a result of the top plate clearance angle and the cutting edge angle, the cutter plunges into the wood as the saw chain moves forwards. Once the top plate cutting edge has gone so far into the wood that the depth gauge touches the bottom of the cut, it levels out and continues running parallel to the bottom of the cut. It is at this point that chip removal takes place. The depth gauge setting thus determines the thickness of the chip removed. The side plate cutting edge separates the chip from the wall of the cut. As the saw chain has alternate right and left hand cutters, chip separation is performed at each side of the cut with every second cutter. The chip removed in this way passes through the chip channel, under the top plate, and into the chip space between the cutters where it remains until the cutters emerge from the cut. The chip is then ejected.

14.1.5 Fitting of the saw chain on the saw Installation of the saw chain is similar for all chainsaws. The procedure is described in detail in the owner’s manual supplied with every chainsaw. There are however a few important points that must be noted: • The chain length (number of drive links) must match the length of the guide bar and the drive link gauge must match the width of the guide bar groove; • The chain pitch must match the pitch of the chain drive sprocket and the nose sprocket; • The guide bar must be compatible with the guide bar mounting and the chain lubrication inlet holes. A new chain drive sprocket should be installed with each new chain. However, as a chain drive sprocket normally has a wear life equivalent to two chains, it is advisable to use two chains in rotation with one sprocket. In this way, the sprocket and chain bed-in with each other and

South African Chainsaw Safety and Operating Handbook 81 wear out together. If a new chain is installed on a half-worn sprocket, its drive links will wear very quickly. A rule of thumb to the economic operation of a chainsaw is to useone guide bar for every two chain drive sprockets and four chains in rotation.

14.1.6 Chain tension A slack or loose saw chain is the cause of most chain problems. Loose chains can: • Climb up on the sprocket; • Damage the guide bar rails; • Cause wear to cutters, tie straps and the guide bar; • Cause the chain to de-rail off the guide bar. Correct tension, break-in and lubrication of the saw chain are individually and collectively of great importance to the service life of the cutting attachment. They also have a major effect on the wear of engine components. Chain tension adjustment procedure: • Never adjust the chain tension with the engine running; • The cold tensioned chain should fit snugly against the underside of the guide bar so that it can still be pulled along the guide bar by hand (Figure 75); • As there is much less friction on the sprocket nose type of bar, the chain can be tensioned more than on solid nose bars; • Press the bar upwards or support it firmly from below when the chain is tensioned and bar nuts are tightened. This will prevent the bar from altering its position once cutting has started and ensure that the correct tension is maintained; • Extreme care should be taken when checking chain tension as the cutting edges are sharp and could cause cuts. Wear both gloves when handling chain; • During cutting, the chain warms up as a result of friction, and expands. This causes the chain to slacken and eventually sag on the underside of the bar, requiring the chain to be re-tensioned; • Chain tension should be checked at frequent intervals in normal working conditions.

Figure 75: The correct tension test with the saw chain on the guide bar

82 South African Chainsaw Safety and Operating Handbook 14.1.7 Running-in the saw chain The chain should be submerged in chain lubricant overnight before use. The chain requires a certain initial period after start-up for the individual components to bed-in. This period is known as break-in or running-in. The break-in time for new chain is about three minutes with the engine running off load (without cutting). As the frictional stress during break-in is particularly high it is essential to ensure adequate lubrication. On machines with a lubrication flow control, the control should be set to maximum flow. During running-in a few light cuts should be made as this facilitates the bedding-in of the individual components. The chain will still stretch a little and therefore it must be re-tensioned during the process.

14.1.8 Chain lubrication Apart from chain tension and regular care and maintenance, lubrication is the factor that has the greatest influence on the life of the cutting attachment. Friction is generated between the sliding faces of the chain links and bar, and also in the chain joints, as the tensioned chain travels over the guide bar. If the bar rails and chain are dry, it results in frictional heat which quickly increases the temperature of the chain and bar and finally causes them to wear at an accelerated rate. It is therefore necessary to introduce a chain lubricant film between the sliding surfaces and joints to reduce friction. Owing to the centrifugal force that occurs as the chain rotates around the bar, a certain amount of chain lubricant is thrown off the cutting attachment. In addition, some lubricant is wiped off the chain in the cut and some is absorbed by the chips. It is therefore necessary to provide an ample and continuous flow of lubrication to the bar and chain whilst the chain is running. The lubrication pump supplies the necessary quantity of lubricant to the bar mounting flange and from there through the inlet hole to the guide bar groove. The drive link tangs distribute the lubricant over the length of the guide bar. Ensure that the chain lubricant never runs out before the fuel. Always refill the lubricant tank to the top. The chain lubrication system can only function if: • The lubricant tank is filled; • The pump is in working order; • The channels, inlet hole and the bar groove are clean.

Chain lubrication must be checked before work commences and at regular intervals during cutting. The easiest way to carry out this check, is to hold the bar tip over a light background (tree stump, sawdust, etc.) with the chain running. Chain lubrication is correct if an increasing trace of lubricant can be seen against this background. The amount of chain lubrication required differs according to the application. Long guide bars, large stem diameters, hard and dry wood as well as thick bark need more chain lubrication; while short guide bars, soft and damp wood would need less. To meet these different requirements, most professional saws are equipped with variable-flow pumps. Some heavy-duty production saws have an additional manual pump to provide the extra lubrication required in certain cutting situations. If the bar begins to smoke whilst cutting (not to be confused with steam) and/or the chain snags in the bar groove, the reason is overheating.

South African Chainsaw Safety and Operating Handbook 83 This may be caused by: • Inadequate lubrication; • A dull or incorrectly sharpened chain; • An over-tensioned chain. Many a chain shows signs of advanced wear on the sliding faces and joints due to a lack of proper lubrication even though the cutters are still in good condition. The quality of the lubricant is vitally important for the efficiency of chain lubrication and thus the life of the cutting attachment. In addition to good lubricating properties, chain lubricant must have the following characteristics: • Good adhesive properties (tacky additive) to ensure that the minimum of lubricant is thrown off the cutting attachment by centrifugal forces; • A high flash point to ensure that it cannot be ignited by the heat generated during cutting; • Wear protection to ensure that wear on the chain and guide bar is reduced to a minimum; • Refrain from using non-purpose ‘black oils’ (Chapter 3.2).

14.1.9 Sharpening The sharpening procedure is basically the same for all chains but different filing angles and settings are necessary for different chain types.

14.1.9.1 When to sharpen A properly sharpened chain pulls itself into the cut when only slight pressure is applied. If the chain has to be forced into the cut by applying excessive pressure, the cutters are dull or have been damaged. Frequently, more chainsaw power is used to compensate for poor sharpening, instead of better training and discipline regarding chain maintenance. Another clear indication of a dull chain is fine sawdust (Figure 76a) being pulled from the cut instead of course, thick chips (Figure 76b).

A B

Figure 76: Saw dust indications of a) blunt saw chain and b) sharp saw chain

Working with a dull chain means loss of power, high fuel consumption and a higher rate of wear on the cutting attachment and engine. It can also lead to operator fatigue which in turn increases the risk of accidents.

84 South African Chainsaw Safety and Operating Handbook 14.1.9.2 Preparing saw chain for sharpening The chain must be examined carefully for damage. Any damaged links, particularly cutters with badly nicked or chipped cutting edges, must be replaced. The cutter with the shortest top plate must be found as it is this cutter that is used as the master for sharpening (Figure 77).

Figure 77: Shortest top plate

All cutters must be the same length and shape (balance) after sharpening. Owing to the rearward slope of the top plate, the cutter heights will be uneven if the cutter lengths are different. If the cutters are not the same height, the chain will cut roughly and may break. After the chain has been re-sharpened, the filings can be removed from the bar groove by running the engine briefly off load at full throttle.

14.1.9.3 Cutter sharpening terminology To sharpen a saw chain the operator must understand the following: • The side plate angle (Figure 78) is the angle between the side plate cutting edge and the horizontal line formed by the cutter toe and heel. This angle varies on individual chain types;

Figure 78: Side plate angle

South African Chainsaw Safety and Operating Handbook 85 • The top plate filing angle (Figure 79) is the angle measured from the top plate cutting edge at a right angle to the guide bar;

Figure 79: Top plate filing angle

• The filing angle differs on individual chains. The standard filing angle for normal applications is 25°- 30° as specified by the manufacturer. Wider filing angles increase cutting performance in softwood. Narrower filing angles ensure a smoother running chain and less vibration in hardwood. The side plate angle and top plate filing angle have a significant influence on the chain’s ability to cut wood and therefore it is essential to maintain the specified values. • The depth gauge is the small projection in front of the cutting edge. The difference in height between the top of the depth gauge and the leading edge of the top plate is known as the depth gauge setting (Figure 80). It determines the height at which the cutter enters the wood (chip thickness) and therefore has an influence on chain cutting capacity.

Figure 80: Depth gauge setting

14.1.9.4 Filing the chain Use the correct tools according to the manufacturer’s specifications. The following is needed to file the chain (Figure 81): • Round file for cutters; • File holder or file augeg for cutters; • Flat file for the depth gauges; • Depth gauge tool (It can be incorporated into the file gauge). It is the operator’s responsibility to make sure the chain is in a workable and safe condition. As a general rule the chain should be sharpened after each fuel refill, and the depth gauge checked after every second fuel refill.

86 South African Chainsaw Safety and Operating Handbook Figure 81: Tools to sharpen the saw chain (a) round file and file holder; (b) depth gauge tool; (c) flat file; (d) sharpening tool pouch

New sharpening and depth gauge technology include devices that sharpen and adjust the depth gauge at once (Figure 82).

A B

C

Figure 82: Chain sharpening technology. a) round file gauge, including b) depth gauge and c) all in one sharpener and depth gauge filer (follow suppliers’ guidelines)

South African Chainsaw Safety and Operating Handbook 87 Round file cutter sharpening Use the correct round file and file holder/gauge. Standard round files are not suitable for filing saw chain. Sharpening with a round file is performed in such a way that the file is set with part of its diameter protruding above the top plate according to the manufacturer’s specifications (Figure 83). The use of a file holder/gauge ensures that the file is kept at the correct height.

Figure 83: Sharpening with a round file showing part of file diameter protruding

Sharpening begins at the master cutter (shortest top plate). File holders/gauges have reference lines showing the correct filing angles (Figure 84). Place the file holder/gauge in position. It is held so as to maintain the specific top plate filing angle required. The reference line must be parallel to the guide bar during filing.

Figure 84: File holder showing correct filing angle and reference lines on sharpening guide

To obtain the correct side and top plate cutting angles, the file holder must be held horizontally or at the angle specified by the manufacturer (Figure 85).

Figure 85: File holder held horizontally

88 South African Chainsaw Safety and Operating Handbook Sharpen all cutters on one side of the chain first. File from the inside to the outside of each cutter. Repeat the process for cutters on the other side of the chain. Filing must be performed on the forward stroke only. The file must be lifted off the cutter on the backstroke. To achieve smooth faces and sharp cutting edges it is necessary to file evenly and steadily. If the same number of file strokes and the same pressure is used on each cutter, cutters of similar length will be obtained. Two or three strokes of the file are usually sufficient. The basic rule is to file frequently and take away as little material as possible.

Filing the depth gauge The depth gauge setting must be checked regularly. The settings differ according to chain pitch; therefore the correct depth gauge tool must be used. If the depth gauge projects from the depth gauge tool it must be filed down level with a flat file (Figure 86).

Figure 86: Filing down the depth gauge

If the cutters are sharpened with two to three light strokes of the round file the depth gauges do not need lowering every time. When all depth gauges are level, their front edges must be rounded to the original profile (Figure 87).

Figure 87: Rounding the front edge of a depth gauge with a flat file

South African Chainsaw Safety and Operating Handbook 89 14.1.9.5 Sharpening errors The specified shape of the cutters can only be obtained if the correct tools are used (file and file holder/gauge for manual sharpening, or specially shaped grinding wheels) and the correct adjustments made. Every deviation affects at least one of the fixed factors. For example, if the file is too thin or the file holder sets the file too low, the side plate and top plate cutting angles will be too small (a hook). Similarly, if the file diameter is too large or the file is set too high, the resultant side plate and top plate cutting angles will be too large (a back-slope). The top plate cutting edge is the major cutting edge on the cutter. Although it is difficult to measure, it will automatically be correct if the other specified angles are maintained. Common sharpening errors include the following (Figure 88):

Cutter lengths not uniform Irregular top plate angles

Different side plate angles Uneven depth gauges Figure 88: Sharpening errors on the saw chain

14.1.9.6 Replacing chain links Owing to the relatively high chain speed, any contact the chain, and particularly the cutters, make with hard materials (metal, stone, etc.) has a destructive effect on the chain links concerned. Errors in sharpening and incorrect chain tension can also cause damage to individual links. Badly damaged cutters cannot always simply be filed back because they would then be much shorter (and lower) than the other cutters. They must be replaced like any other faulty links. There are several methods of repairing chain links. Chain breaking and rivet spinning tools should be used (some types are portable, hand-held while others require a firm mounting base). Repairs must be in accordance with the operating instructions supplied with the unit. To ensure flawless operation of a repaired chain, it is essential to adhere to the following general rules:

90 South African Chainsaw Safety and Operating Handbook • The assembly sequence of the chain links must never be changed. The link removed must always be replaced by one of the same type; • Rivets should always be formed or spun so that they link freely but with a minimum of play. In all cases new rivets should be used when joining a chain; • The newly fitted chain link must be matched to the other links. The cutter and depth gauge must be filed back to the size of the master cutter and the bottom faces filed back to match the worn cutters.

14.2 Guide bars 14.2.1 Guide bar design Ensure that the correct guide bar for the specific make and model of chainsaw is purchased and that it is compatible with the saw chain. The chain lubrication holes must also match. Generic parts of the guide bar consist of the following (Figure 89). A continuous groove or chain gauge is machined into the outer edge of the guide bar. The tangs of the drive links extend into the guide bar groove to keep the saw chain running in a straight line, while the bottoms of the tie straps and cutters ride on the rails on either side of the groove. The guide bar groove also serves as a supply channel for lubricant.

1. Guide bar mounting area 2. Tail 3. Slot for the mounting nuts 4. Fixing hole chain 5. Lubrication inlet 6. Chain gauge (groove width) Figure 89: Guide bar

South African Chainsaw Safety and Operating Handbook 91 Four different characteristics are used to select and define a guide bar: • The guide bar tail and bar mounting area assigns the guide bar to specific chainsaw models. The tail is characterised by the contour of the tail itself, the shape and position of the slot for the mounting studs and the position of the chain lubrication inlet and fixing holes. • The groove width refers to the inside width of the groove that must match the drive link gauge. • The guide bar is characterised by, Figure 90 (a) the cutting length and (b) the overall bar length.

Figure 90: Guide bar (a) cutting length and (b) overall guide bar length

14.2.2 Types of guide bars The production of guide bars can in principle be divided into 2 categories: • Laminated bars are manufactured using a sandwich technique, i.e. three different pieces are welded together to create a unit; • Solid bars are manufactured from a single piece of metal. Bars can be solid nosed or fitted with a sprocket. Bars with sprocket noses produce significantly less friction than solid nose bars. For highest efficiency, bars with sprocket noses are recommended.

Sprocket nose guide bar The sprocket is replaceable (Figure 91). Friction and wear on the guide bar nose are substantially reduced compared to solid nose bars (rolling friction instead of sliding friction). The reduced friction enables the chain to be run with more tension.

Figure 91: Sprocket nose guide bar

92 South African Chainsaw Safety and Operating Handbook These guide bars have a higher cutting capacity than solid nose bars. Bore cuts are also easier and safer to perform. Lower rate of frictional wear and higher cutting capacity also have a positive effect when debranching, i.e. cutting alternately with the top and the bottom of the guide bar. These guide bars are ideally suited for felling smaller trees and debranching.

Replaceable sprocket nose guide bar On this type of guide bar the entire nose or only the sprocket can be replaced (Figure 92). These guide bars combine the high strength and robustness of solid guide bars with the high cutting performance of the sprocket nose. They are recommended for use with long guide bars to reduce the load on the bar tip. The load is transferred to the high quality roller bearing. These guide bars are ideally suited for very demanding professional felling and cross-cutting on high powered, heavy duty chainsaws.

Figure 92: Replaceable sprocket nose guide bar

Solid nose guide bar These bars and are sometimes called “stellite tip” bars and are made in a single piece from specially formulated steel (Figure 93). Their great resilience makes them highly resistant to flexing stresses and warping. The rails are hardened and the highly stressed nose area is stellite tipped.

Figure 93: Solid nose guide bar

These guide bars are ideally suited for heavy-duty professional felling and cross-cutting on high powered saws for large trees and in extreme conditions.

South African Chainsaw Safety and Operating Handbook 93 14.2.3 Guide bar care As mentioned earlier, the cutting attachment is subject to high wear. The guide bar wears particularly in the area where most of the cutting is done, normally the underside of the bar. To ensure that the guide bar wears evenly on both sides, it should be turned over every time the saw chain is removed. The chain lubrication inlet holes and the bar groove should be cleaned thoroughly at the same time using a groove cleaner.

14.2.4 Guide bar maintenance Once a guide bar has been in use for an extended period the groove depth should be measured before a sharpened chain is fitted. The measurement is taken in the area where most of the cutting is done on the guide bar. If the measured depth is less than the minimum specified by the manufacturer, the guide bar must be replaced.

14.2.4.1 Dressing guide bar rails to remove burrs Burrs on the guide bar rails result from normal wear over time (Figure 94). These burrs are raised sections on the edge of the bar. Remove the burrs regularly with a flat file, filing at a 45° angle.

Figure 94: Burs forming on the edges of the guide bar

14.2.4.2 Opening the groove A pinched groove can be opened by means of a tool that matches the specified groove width. This is done by clamping the guide bar in a vice and inserting the tool in the groove at an angle of about 45°, at a point where the width is still correct. A hammer is then used to knock the tool through the pinched portion of the groove. If the groove is badly distorted, it may be necessary to repeat this process several times until the saw chain can be pulled along the bar without resistance. There is a risk of cracking the guide bar during this process, particularly at the nose of solid nose bars. Therefore the guide bar must be examined for cracks after the groove has been opened. If any are found, the guide bar must not be used again.

94 South African Chainsaw Safety and Operating Handbook 14.2.4.3 Replacing the sprocket The sprocket must be renewed if the teeth are worn or the roller bearing is damaged. To remove the sprocket, first knock out the countersunk rivets. This is done by drilling away the heads of the rivets with a drill (about 0.5 mm diameter larger than the rivet head) and knocking out the rivets with a punch. The sprocket assembly can now be pulled out together with the bearing. To ensure flawless operation, it is essential to replace the complete sprocket assembly. It is very important that the correct sprocket is used for the specific guide bar. An illustration of a removable sprocket and its components appears in Figure 95.

Figure 95: Components of a removable sprocket guide bar

After the replacement sprocket has been positioned, the bearing race must be turned so that its holes line up with the holes in the guide bar nose. The countersunk rivets can then be inserted and peened in a press if possible. To prevent the end of the guide bar nose opening up, a vice grip may be used to clamp down the nose during the peening process. A hammer is then used to form the rivet heads so that they completely fill the hole recesses. The sprocket bearing must be thoroughly lubricated before the repaired guide bar is used for cutting (e.g. by immersing the guide bar nose in chain lubricant).

14.2.4.4 Replacing the replaceable nose On guide bars with a riveted guide bar nose, the complete nose can be replaced. Disassembly is carried out by drilling off the rivet heads, knocking out the rivets with a punch and simply pulling the sprocket nose away from the guide bar. Once the new sprocket nose has been installed, the rivets are formed as previously described (Figure 96).

Figure 96: Replacing the nose

South African Chainsaw Safety and Operating Handbook 95 It is necessary to check whether the guide bar and sprocket nose rails are at the same height. If not, the projecting rails must be filed down to the same level (Figure 97).

Figure 97: Filing down projecting rails

14.3 Chain drive sprocket 14.3.1 Construction and mechanical function The individual parts are illustrated in Figure 98.

1. Spur sprocket 2. Rim sprocket 3. Bar 4. Saw chain

Figure 98: Chain drive (1) spur sprocket; (2) rim sprocket; (3) bar; (4) saw chain

The chain drive sprocket transmits the engine’s torque to the saw chain. The teeth of the chain drive sprocket transfer the power to the drive link tangs and the chain is propelled around the guide. The sprocket teeth are designed to mesh exactly with the drive link tangs. The number of teeth on the chain drive sprocket has a direct influence on the speed of the saw chain. The greater the number of teeth the higher the chain speed, and vice versa. The sprocket and saw chain pitch must match. The diameter of the sprocket must not be less than the guide bar tail as this governs the angle of drive link run-in to the guide bar groove.

96 South African Chainsaw Safety and Operating Handbook 14.3.2 Types of chain drive sprockets 14.3.2.1 Spur sprocket A spur sprocket (Figure 99) consists of a highly wear resistant star section that is welded to the clutch drum.

Figure 99: Spur sprocket and clutch drum and bearing

14.3.2.2 Rim sprocket The rim sprocket (Figure 100) is made from sintered steel and is ring-shaped. The teeth are enclosed on both sides by a circular wall. The sprocket can move axially on the hub of the clutch drum and is positively located by means of splines.

Figure 100: Rim sprocket, clutch drum, bearing and c-clamp attachments

Advantages of the rim sprocket: • The bottom faces of the chain links ride on the circumference of the rim so that the sprocket’s teeth only perform the actual driving function, i.e. are subjected to less strain; • The side walls of the rim keep the saw chain in line, i.e. the rim automatically aligns itself relative to the guide bar groove, resulting in a smooth running chain and less wear on the guide bar groove entry area and the chain.

South African Chainsaw Safety and Operating Handbook 97 14.3.3 Sprocket wear The continuous driving action gradually wears the chain drive sprocket and results in the drive link tangs digging into the flanks of the teeth. On the spur sprocket there is a second cause of wear. The bottom of the cutters and tie straps (actually the notch between the heel and toe of the link) also cut into the tips of the sprocket teeth. On a rim sprocket, wear is primarily visible on the circumference. A new chain drive sprocket must always be installed with a new chain as a worn sprocket will ruin a new chain. Wear gauges are available to measure rim sprocket wear for replacement.

98 South African Chainsaw Safety and Operating Handbook Chapter 15: Chainsaw maintenance

Maintenance is essential to prolong the life of the chainsaw, maximise productivity within the prescribed safety standards and to minimise downtime. To maintain is cost effective and to repair when broken is costly. Whilst specific maintenance requirements may vary between different makes and models, there are certain general guidelines for preventative maintenance that must be followed. Maintenance intervals should be shortened in extreme working conditions. Remember to consult the owner’s manual for specific requirements. Only maintenance that is to be performed by the chainsaw operator is included in this Chapter.

15.1 Safety requirements The following safety requirements must be adhered to during maintenance: • Always stop the engine and ensure that the saw chain has stopped before attempting any work; • Do not attempt any work not qualified to do; • Never test the ignition system with the ignition wire terminal removed from the spark plug or an unearthed spark plug, since uncontained sparking will damage the electronic ignition and may cause fire; • Use only safe areas for maintenance; • Comply with the requirements for refuelling. (Refer to Chapter 15.2).

15.2 Refuelling The following must be adhered to when refuelling: • Do not refuel with the engine running; • Use only fuel and lubricants recommended by the manufacturer; • Do not smoke whilst refuelling; • Keep the fuel clean at all times; • Keep a fire extinguisher available at a demarcated area; • Use the correct fuel/oil (2-stroke) mix as per manufacturers recommendation; • Remove all flammable debris such as needles or leaves, leaving a small area of ±1 2m exposing bare soil. Thus, refuel in a safe place and guard against fire hazards; • Use a can with a suitable spout to avoid spillage during refuelling (Non-spill combi-can is preferable (Figure 101). All fuel holders must be made from static electric resistant material. • Clean the filler caps and the area around them to ensure that no dirt falls into the tank; • Remove the fuel filler cap carefully to allow any pressure build-up in the tank to release slowly; • Shake the mixture thoroughly before refuelling; • Refill the chain lubrication tank first to the required level (irrespective of the level of the chain lubricant) before refuelling commences. Then refill the fuel tank to the required level. This will ensure that refilling the chain lubrication tank is not forgotten and the chainsaw can be allowed to cool; • Tighten filler caps securely, taking care not to cross thread;

South African Chainsaw Safety and Operating Handbook 99 • Wipe any accidental spillage off the chainsaw and allow time for spilled fuel to evaporate before starting; • Do not start the chainsaw where it was refuelled. Move at least 3 m away from the place of refuelling. Start the chainsaw only once refuelling and other checks have been completed; • Leave the refuelling can in a safe area after refuelling.

Figure 101: Examples of manufacturer combi-cans

15.3 Maintenance Saw maintenance ensures safe and productive use.

15.3.1 Pre-operational checks To ensure safe and efficient operating of the chainsaw, it is imperative that the chainsaw operator checks the following before work commences: • Inspect the complete machine visually to ensure that it is in a serviceable condition; • Check the operation of the chain brake; • Check the chain catcher; • Inspect saw chain and chain tension;

100 South African Chainsaw Safety and Operating Handbook • Check for wear and damage to the guide bar; • Check the muffler assembly; • Start the chainsaw and check the following: ▪▪ Ease of starting; ▪▪ Idling; ▪▪ No chain creep; ▪▪ Chain lubrication. • Check the operation of the throttle trigger, throttle lockout and the on/off switch;

15.3.2 Ongoing maintenance The chainsaw operator must monitor the general chainsaw performance throughout the operation. If a decrease in performance is detected it should immediately be attended to and/ or reported. During each refuelling stop it is recommended that the chainsaw operator does the following: • Inspect the complete machine visually to ensure that it is in a serviceable condition. Inspect the chainsaw for loose or missing screws, clogged air intake vents and loose covers; • Check the operation of the throttle trigger, throttle lockout and on/off switch; • Inspect and sharpen the saw chain; • Check the chain tension; • Check the idling; • Check the chain brake; • Refuel the chainsaw.

15.3.3 Daily maintenance At the end of each working day the chainsaw operator must perform a simple but most important daily service. The importance of the daily service is that during this service small problems may be detected and rectified before they turn into larger problems. Guidelines for a daily service are as follows: • Clean the chainsaw and accessible components. Ensure that all air intake areas are clean. A dry clean using compressed air is preferable; • Do a visual inspection of the complete machine. Check the chainsaw condition and check for loose/missing nuts and bolts and tighten/replace them; • Check all safety features for damage and effective functioning: ▪▪ Chain brake and chain brake lever; ▪▪ Chain catcher; ▪▪ Muffler; ▪▪ On/off switch; ▪▪ Throttle lockout and control trigger; ▪▪ Rear hand guard; ▪▪ Anti vibration system. • Check and clean/replace the air filter as per the manufacturer’s requirements; • Check the starter grip and starter cord for wear, damage and functioning. Clean the air intake slots on the starter cover; • Check the guide bar, saw chain and chain drive sprocket for excessive wear or damage:

South African Chainsaw Safety and Operating Handbook 101 ▪▪ Clean the guide bar groove and chain lubrication holes; ▪▪ Remove burrs from the guide bar if required; ▪▪ Turn the guide bar daily to ensure even wear; ▪▪ If the guide bar has a sprocket nose, lubricate it when required, or as per the manufacturer’s requirements; ▪▪ Fit the guide bar, saw chain and clutch cover; ▪▪ Sharpen the chain; ▪▪ Check the depth gauge settings. • Start the machine and do the standard field test by checking: ▪▪ Starting ability – easy starting; ▪▪ Idle ability; ▪▪ Acceleration response – should be instantaneous; ▪▪ Chain lubrication feed – is the chain and guide bar receiving sufficient lubrication? ▪▪ Cutability – make a few light cuts in a log to ensure a smooth, unforced cut; ▪▪ On/off switch function; ▪▪ Test the chain brake once acceleration has been achieved. • Remove the chain and guide bar for storage in a chain lubrication bath; • Ensure that fuel and chain lubrication tanks are full. The daily service takes approximately 20 minutes to perform, and ensures a functional and reliable chainsaw for the following day’s task. Any faults should be reported to the chainsaw mechanic or supervisor and be attended to.

15.3.4 Operation in burnt timber Cutting burnt timber is classed as an adverse application whereby no chainsaw has been purposely built or designed to handle effectively. This type of application is not the norm and it is obvious that efficiency levels, productivity levels and running costs, will be somewhat adversely affected compared to a non-burnt timber application. Working in burnt timber can increase the wear and tear on the components by up to 50%. The carbon (charcoal) on timber that has been burnt is extremely brittle and when the cutters on a chainsaw’s chain strike this carbon it shatters it into minute dust particles. These fine particles stay suspended in the air around the chainsaws for some time. This carbon dust is also exceptionally abrasive. There are certain measures that can be taken in an attempt to minimise the damage that will be caused by the “charcoal” when it comes into contact with the engines components: 1. Air Filtration – A standard felt or flock air filter is made of material that will block particles larger than 30 microns in size. It is almost impossible to prevent the fine carbon dust, together with other impurities that are already in the air, being drawn into a chain saws air intake system. This can be done by using a: a. Filter Sock – A filter sock made from selected density foam can be used over the existing air filter as a pre-filter. These are high maintenance components and careful monitoring is required. Improving the effectiveness of these components can be done by: • Lightly oiling the filter sock or pre-filter with an air filter oil to improve its filtration ability. This can also be done on the short term by soaking the pre- filter in a bit of fuel mix then squeezing the excess fuel.

102 South African Chainsaw Safety and Operating Handbook • As soon as there is a noted loss of power or performance of the engine, the pre-filter is likely blocked. The pre-filter should be changed or thoroughly cleaned before being replaced. This may occur many times a day, and a stock of filters is recommended to keep down time low. b. Heavy Duty (HD) Filter – A heavy duty filter is available for some chainsaw models. These filters have a larger filter surface area which helps by extending change intervals. A filter sock should be used in conjunction with the HD filter. 2. Refuelling Contaminants entering the fuel tank that can either pass through or block the fuel filter. Carbon entering the carburettor will increase/speed up the wear to the carburettor components. If the fuel filter gets blocked, the engine will run lean as the air/fuel relationship will be affected and cause component failure. Preventive measures that should be taken include: a. Ensuring the refuelling zone is properly cleared out; b. Wipe or brush dirt from the fuel filler cap before loosening the cap; c. Using fuel containers with a specialised non spill fuel spout will reduce the possibility of washing dirt into the fuel tank. 3. Engine Lubrication. It is impossible to completely eliminate carbon getting into the engine. A good quality 2-stroke oil (synthetic or semi-synthetic) can be used to help improve lubrication under these adverse conditions thus reducing the working heat range of the internal components; 4. General Maintenance. Allowing as much air as possible to flow over the cylinder will help prevent over heating of the engine. Components requiring special attention are: a. Air Intake. The vents on the starter housing must be kept free of wood shavings and dirt to allow air into the flywheel area; b. Flywheel. The fins on fly wheel blow cool air over the cylinder. Air flow is reduced when these become dirty; c. The Cylinder Cooling Fins. These must be kept clear and clean of any dirt. Dirt will act as a heat insulator and will cause the engine temperature to rise. Keeping the fins clean will help prevent overheating of the engine.

Chainsaws are not designed to effectively cut burnt timber. If all preventative maintenance measures are adhered to, it will certainly increase the components life to some degree but please note that the components will also wear prematurely from what is normally realised. The warranty of the chainsaw may be effected when used to harvest/cut burnt timber.

South African Chainsaw Safety and Operating Handbook 103 104 South African Chainsaw Safety and Operating Handbook Chapter 16: References and further reading

Department of Labor and Industries, 1994. Safety Standards for Logging Operations. Division of Consultation and Compliance, State of Washington, USA. Department of Labour, 1993. Occupational Health and Safety Act (Act 85 of 1993). Government Press, South Africa. Forest Engineering Southern Africa, 1998. South African Cable Yarding Safety and Operating Handbook. FESA, South Africa. Forest Engineering Southern Africa, 1998. Noise Level Evaluation of Forestry Equipment. Technical Note TN-1/98, FESA, South Africa. Gaskin JE and Parker JE. 1993. Accidents in forestry and logging operations in New Zealand. Available at: http://www.fao.org/docrep/u8520e/u8520e05.htm [Accsesed: 07 Febuary, 2014] Husqvarna. Chain Saw Operator’s Safety Manual. Bratts, Tryckeri, Sweden. Husqvarna. 2014. Working with chainsaws Part 1 and part 2. Husqvarna, Sweden. Husqvarna. Chain Saw Technique. Husqvarna, Sweden. Husqvarna. Operator’s Manual 365/371XP. Husqvarna, Sweden. Husqvarna. Husqvarna Catalogue. Husqvarna, Sweden. ILO. 1991. Proc. Occupational Safety and Health in Forestry. Forestry and Wood Industries Committee, Second Session. Geneva, ILO International Labour Organization. 1998. Safety and Health in Forestry Work – An ILO Code of Practice, ILO, Geneva. Jones AT and Smith RO. 1980. Harvesting Windthrown Trees. Forestry Commission, Leaflet 75, London, UK. Occupational Safety and Health Service. 1993. A Guide to Safety with Chainsaws. Department of Labour, New Zealand. Occupational Safety and Health Service. 1994. A Guide to Safety in Tree Felling and Cross Cutting. Department of Labour, New Zealand. Occupational Safety and Health Service. 1995. Safety Code for Forest Operations – Part 3: Logging. Department of Labour, New Zealand. Oregon Cutting Systems Division. 1996. Maintenance and Safety Manual. Belgium Oregon Occupational Safety and Health Division. 1992. Oregon Occupational Health and Safety Code. Department of Insurance and Finance, USA Parker RJ. 1992. Analysis of lost-time accidents 1991 (Accident Reporting Scheme Statistics). LIRO report, Vol. 17, No. 8. Rotorua, New Zealand, LIRO Pyykkö I, Sairanen E, Korhonen O, Färkkilä M and Hyvärinen J. 1978. A decrease in the prevalence and severity of vibration-induced white fingers among lumberjacks in Finland. Scandinavian Journal of Work, Environment & Health. 4(3): 246-254. Safcol. Chainsaw operator. Safcol, South Africa Stihl. 1997. Chain and Bar Manual. Stihl, Germany. Stihl. 1998. Chain Saw Safety Manual. Stihl, Germany. Stihl. 1998. Instruction Manual Stihl 038. Stihl, Germany.

South African Chainsaw Safety and Operating Handbook 105 Stihl. 1998. Stihl Catalogue. Stihl, Germany. Timber Industry Manpower Services. 1980. Chainsaw Handling. TIMS, South Africa. Upfold SJ and Ackerman SA (Eds.). 2014. Forest Engineering Southern Africa - Guidelines for Forest Engineering Practices in South Africa. FESA and ICFR. South Africa. Waiariki Polytechnic. Chainsaws. Waiariki Polytechnic, New Zealand. Zaremba W. 1976. Logging Reference Manual – Volume 2. Department of Forestry, Pretoria, South Africa.

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