Trimming branches and tree limbs growing

Transcription

1 Tree trimming Trimming branches and tree limbs growing near, or in possible contact with, overhead power or communications lines is a potential source of trouble and can cause service interruptions. Broken branches and limbs can fall across lines and break wires or act as conductors between wires when wet. Broken branches or the wind can force wires together, causing shorts or burnouts (Figure 1). This data sheet discusses the hazards surrounding tree-trimming operations and ways to avoid injury. 2. Tree trimmers commonly suffer minor injuries, such as cuts and bruises from contact with tree limbs and machinery. Major hazards include: Falls from trees Contact with energized limbs Falling trees and falling limbs Improper climbing and working methods High-speed moving parts on power equipment (e.g., stump grinders, chipper) Units and power saws High noise levels from power machinery Working in aerial baskets Trimming programs 3. Regular tree-trimming programs can prevent the occurrence or recurrence of hazardous conditions. It may be necessary to trim trees before they reach wires to assure safe clearances or to remove broken, dead and overhanging limbs. Sometimes an entire area will need to be cleared. 4. Employers must train and instruct employees in the hazards involved in their job assignments. Training should include techniques for proper handling of all equipment used in tree work, maintenance and Figure 1. A tree trimmer is preparing to remove an overlapping branch near high-powered service lines. removal operations (Figure 2). Employers should document that employees have satisfactorily completed the training program before performing the job assignment. 5. A safe tree-trimming program should include: Safety rules that are observed Selection of qualified, well-trained workers 1

2 Selection, use and maintenance of proper tools and equipment Adequate first aid equipment and trained staff to administer it An accident prevention program and appropriate accident recordkeeping 6. A typical, supervised tree-trimming crew should have at least two climbers and a combination truck driver and brushman to promote safe operation where heavy trimming and topping are necessary. There are line workers or troubleshooters who do spot trimming for specific emergency problems involving wires or public hazards; these spot trimmers should have an experienced helper who can join the team in an emergency or under adverse conditions. For seasonal tree crews, some small utility and transportation companies and some municipalities recruit employees from various departments, but this is not recommended because these employees usually have limited experience and may not have adequate tree-trimming equipment available. Role of supervisor 7. Supervisors must be familiar with the skills and operations needed to perform a tree-trimming job safely. They should follow five general rules: Verify that employees are physically and mentally fit for trimming operations. Never use workers who are under the influence of alcohol and/or controlled substances. Never allow horseplay on the job. Have a qualified assistant who can assume control of the crew when needed. Always have one person on the ground when tree work is being done. 8. Supervisors should evaluate skills, experience and medical histories of workers and then try to match each worker to the job. Figure 2. A supervisor is instructing a tree-trimming crew during a group training course. At least one qualified assistant should be selected. No crew should work without supervision. 9. Before each job, supervisors should brief all workers on the tasks to be performed and any hazards of the work; inspect all tools, equipment and protective gear; and replace defective or worn tools. The defects should be noted on tags before returning the tools to the shop or tool room for replacement. 10. Supervisors should be consulted when considering tools and equipment for purchase. Changing a tool or material can enable the crew to work more efficiently and safely. Standard equipment 11. Types of equipment vary the equipment used should meet all current ANSI and OSHA standards (ANSI Z ). Work positioning saddles 12. Workers should use tree-trimming sad- 2

3 dle belts and a safety strap during climbing operations (Figure 3). 13. Tree-trimmer saddles used for climbing operations shall meet the same design criteria as outlined in OSHA subpart M for the manufacturing of full-body harnesses. Each climber should have at least one handline. The lines should be a synthetic material, minimum 1 2-inch width and a tensile strength over 5,000 lbs. Pole pruners 14. Pruners should have handles that have adequate strength and a minimum of moisture absorption. Note: Compounding handles located midway along the handle are not recommended because they tend to catch on limbs and branches. 15. Ladders of metal or other electrically conductive material should not be used. Wooden ladders that conform to ANSI standard ANSI A are recommended. Straight ladder or extension ladder side rails should be provided with slipresistant devices such as spikes, slipresistant feet or similar attachments. Some ladders have their top rung made of fabric so it will conform to the shape of a tree. Saws 16. A saw should have a fiber or leather guard with a snap, so it can be held by a ring on a worker s belt during work or while changing position on a tree. Figure 3. This tree trimmer s saddle belt is made of nylon-reinforced fabric with the climbing rope tied into a steel harness strap and the fixtures snapped into rings of the belt. The wires have been de-energized. (Photo courtesy Asplundh Tree Expert Co.) Personal protective equipment 17. Proper clothing is important in accident prevention: workers should not wear loose, floppy clothing, ragged gloves or worn-out shoes. Safe clothing for regular tree-trimming crews should consist of high-top leather shoes with composition soles and heels, a long-sleeved sweatshirt or closefitting jacket, a cap and soft, leather gauntlet gloves. 18. For spot trimming or short-term trimming operations, workers can wear rubber boots in place of composition-soled shoes. If overalls or regular work trousers are worn, the cuff area of the pant legs should be wrapped around the ankles and tied, a minimum of a long-sleeved shirt, a hard hat and quality work gloves should be worn. 19. Tree-trimming workers always should wear personal protective equipment while trimming trees. Approved hard hats and eye protection (ANSI Z87.1) should be worn by workers engaged in tree-trimming operations. PRACTICES AND PROCEDURES Climbing 20. Before climbing or applying weight to any tree, workers should inspect tree limbs for structural weakness. Climbing workers 3

4 should not trust a dead branch to support their weight. Dead branches should be broken off as workers ascend. Hands and feet should be placed on separate limbs, if possible. 21. The location of all electrical conductors in relation to work procedures should be noted. The workers should climb on the side of the tree that is away from electrical conductors, if possible. 22. When working above the ground, workers should be tied in with an approved climbing rope and saddle belt. The climbing rope should always be used even when the work is being performed from a ladder or scaffold. A lanyard for fall protection should be used whenever possible. 23. In some metropolitan areas where trees are close to or overhang a street, trucks with a telescoping tower, hydraulic lifting devices (aerial sky baskets) or telescoping ladders are used to reach the main supporting limbs. Trimming can be performed directly from this equipment or the equipment can be used to hoist workers into the work area of a tree. 24. Outrigger stabilizers on high-lift trucks should be fixed on the ground to decrease overbalance and rollover potential before operating any lift device. A steel snap meeting OSHA fall arrest standards may be used. Aerial lift truck units should be operated only by qualified personnel according to the manufacturer s operation instruction manual. Repairs to the elevating mechanism or its controls should be made only by authorized representatives of the manufacturer. Note: Hydraulic aerial basket devices should be insulated if they are to be used for line clearing. Wooden aerial ladders shall not be considered insulated devices, and they should never be positioned over live conductors. 25. When using hydraulic lifting devices, operators should not depend on the boom and associated equipment for insulation. Operators should be warned not to raise and project booms over live conductors. (Insulated devices are available that can be used safely over live conductors.) 26. For unusual jobs, when it is necessary to get near or between live conductors, the utility company should be notified to cover the wire with rubber protection (insulating line hose), relocate or de-energize the circuit temporarily until the job is completed. 27. Workers sometimes use extension ladders to climb into trees, or trim trees directly from ladders. The side rails of these extension ladders should rest on an adequate surface, and the ladder should be tied to the tree or supported by another worker. 28. When climbing tall trees where the first branches are high and it is difficult or unsafe to use an extension ladder, workers should use climbing ropes. A tree-trimming saddle belt can be used (Figures 3, 4a and 4b). 29. Climbers should be cautioned to select a wide crotch, strong enough to carry their weight, before they throw climbing ropes into a tree. Ropes should be high enough within the tree so they will come to a safe stopping place if another crotch, further up, is used as a safety line support. Use of ropes 30. Workers should be trained to tie the various rope knots and hitches. 31. Ropes should be maintained as follows: Keep ropes coiled when not in use. Carry ropes on the shoulder from one tree to another. This method will keep a rope free of kinks, dirt and sharp grit that can cut the fiber. To open a kink, hold the rope loosely. (Pulling a kink out of a rope damages the fibers.) Store ropes away from all cutting edges and sharp tools. 4

5 Figure 4a and 4b. Workers should respect their safety lines and be instructed not to use them for lowering equipment or limbs. Figure 4b. This is a three-step procedure for tying a tautline hitch knot. Before ropes are used, visually inspect them along their entire length and twist the lay open at intervals for spot-checking. Do not use climbing ropes to lower limbs or other parts of trees. Do not repair climbing and safety ropes by splicing. Rope ends should be secured to prevent unraveling. Figure 4a. These three types of bowline knots can be used for many situations during a tree-trimming operation. Keep corrosive chemicals, gas, and oils away from the ropes. When running ropes through crotches, over limbs or against bark, move them slowly to prevent damage from friction bums. For protection against the weather, cover ropes with a waterproof tarpaulin or place in a ventilated storage box. Wet ropes should not be dried rapidly near a fire or other intense heat; they should be hung up, off the floor or ground, and air-dried. Install ventilated storage boxes or fixtures for holding coils of rope on trucks. Do not leave ropes on floors where they may be cut or damaged by sharp tools (Figure 5). Safe handling of tools 32. A climbing worker should not carry saws, pruners and other tools and equipment; tools should be raised or lowered by handlines. The handline should be attached at the end of the tool (not in the center) so the tool will not slip free, fall or become caught in branches. Canvas buckets are recommended for small tools. 33. To raise or lower a pole pruner, tie ropes below cutting jaws and not to or through the jaws. If a pole is caught in a tree, and the rope is tied to or through the jaws, the rope can be cut and the pruner will drop, injuring workers below. Note: A worker should carry a pruner with the jaw forward and in advance of any worker walking alongside. 34. The following list offers other tips for handling tools: To prevent a saw from falling, fit it with a 5

6 Figure 5. This typical tree-trimming truck has separate storage compartments for ropes, ladders and sharp tools. These separate compartments leave the entire truck body free for brush and limbs. strap or tie rope and secure it to the worker s belt. Remove all tools from a tree when the worker or crew has finished for the day. Do not use axes and hatchets in trees because they might fall and injure workers or cut the supporting lifeline. Keep sheaths or guards on tools when they are in trucks, racks or tool boxes. Hang pull-pruners and pull-saws securely in the vertical position to prevent dislodging. Do not hang pole pruners or pole saws on utility wires or cables or leave in the tree overnight. Hang pull-saws so the sharp edge is away from workers. Power stump grinders 35. A stump grinder is a gasoline-powered mechanical device with rotating teeth that shred tree stumps to below-ground levels. The grinder unit is permanently mounted on wheels and is towed and secured in its operating position by a truck or other automotive equipment. The controls for the grinder are mounted on the side of the unit. From this location, an operator can observe and guide the rotating mechanism at work. 36. The following procedures should be used when operating power stump grinders: The tightness of grinder teeth lock bolts is critical; spot-check it before operations each day. Noise levels should be checked by noise meters. When they are over 85 decibels, operators should wear hearing protection during operation. Operators and workers should wear personal protective equipment (full face shield, goggles, hard hat, gloves and high-top shoes) in the immediate area to prevent injuries from flying chips, rocks, dirt and other high-velocity debris. To provide operators with as much direct protection as possible from flying debris yet not restrict their vision, enclosures or guards shall be installed on the stump grinders. During grinding operations, side tilt of grinder units must be kept within limits that will assure an adequate supply of oil from the pan to lubricate the engine. Grinder shutdown switches must be located within immediate reach of the operator when he or she is in position at the grinder controls during operation. Put the towing truck gear shift lever in neutral before a grinder is started. This will prevent damage to the truck transmission from the severe vibration and rocking motions of the grinder unit during operations. Power chain saws and generators 37. The following list includes important rules for the operation of power chain saws: Supervisors should ascertain that any employee permitted to operate a portable power chain saw is qualified to do so (Figure 6). 6

7 saws from the baskets of hydraulic aerial devices. Note: Small pneumatically, hydraulically or gasoline-powered saws can be used aloft from approved aerial baskets. Figure 6. A trimmer demonstrates the proper way to grip this power chain saw. No one except an operator should be allowed within a radius of 6 feet of a one-person power chain saw when it is in operation, except when it is used aloft in an aerial basket. Small power chain saws, equipped with approved safety cutting chains and weighing not more than 10 lbs., may be used above the shoulder level, provided that the following precautions are observed: a. Saws are suspended from a rope, crotched above the cutting area, while the operator on the ground removes the lower limbs of standing trees. b. To assure the operator s safe footing while de-limbing a felled tree, the severed branches must be removed from the operator s path as work progresses. Approved, small, gasolineor electric-powered chain saws can be used aloft in trees or from an aerial ladder if the saw is supported by a crotched rope independent of the climber s rope. Do not use electrically powered chain When using power chain saws, operators should make certain that they have secure footing. Shut off engines or motors when moving a power chain saw from one location to another, except when trees are close together and the approach is unobstructed. When starting gasoline-powered chain saws with pull cords, hold the saw firmly on the ground or on some solid object. This prohibits starting a chain saw with a pull cord by holding it in an elevated position. Gasoline-powered chain saws with electric starters may be started in an elevated position provided that they are held firmly in both hands. Warning: Starting any chain saw by bracing it against any part of the body or drop-starting is prohibited. Note: Because the cutting chain of power chain saws can run when an engine is started, operators should make sure the immediate area is clear of all personnel and objects before starting an engine. Do not start engines or motors of power chain saws until the saw is in the immediate work area, except when a warm-up period is required. If warm-up is required, do not leave the saw unattended when the power has been turned on. Carry two-person chain saws with the blade indexed to the vertical or bucking position. When carrying one-person saws a long distance to the scene of an operation, 7

8 cover chains suitably; when carrying saws a short distance, covers are not required. Do not insert cutting chains in guide rail grooves while motors are running. All saws operated by two persons should have the transmission horns or tail shock guards held against the material being cut before the cuts are started and during all cutting operations. Directdrive chain saws and one-person gearchain saws should be at full operating speed before a cut is started. Cool hot saws for two or three minutes before refueling. Place a hot saw on a log, stump or on bare ground rather than on dry litter or slash. Refuel in an area free from flammable materials. Maintain metal-to-metal contact between the gasoline can and the gas tank while refueling a saw. Note: Prohibit smoking while a tank is being filled, and keep approved fire-fighting equipment available in accordance with safety standards. Move saws at least 10 feet upwind from the spot of refueling before starting a motor. Equip gasoline-powered saws with mufflers to prevent escape of burning carbon particles from the exhaust. Ground portable generators and portable, electrically powered tools as follows: a. Connect the generator frame to a driven ground rod or other suitable ground. b. Connect the noncurrent-carrying parts of the tool and generator frame with the ground wire of the threeconductor cord through an approved connector. Handle portable, electrically powered tools, cords and generators with care. Store the tool and generator when not in use. Inspect electric saws carefully before use. They should be turned in for thorough inspection after every 60 running hours. Generators, including ground rod and cord, should be returned for inspection after every 120 running hours. Chain saw operators should wear approved eye protection. Noise levels should be checked by noise meters. When they are over 85 decibels, operators should wear hearing protectors. Power loaders 38. A power loader is a truck-mounted, hydraulically powered boom and clamshell device, designed to pick up and load brush and small logs (Figure 7). Some units are combination power loaders and haulers with controls mounted over the truck cab and truck beds designed to carry tree trimmings. Many loaders of this type also can dump loads. Other power loaders are single-purpose vehicles with the loader boom, operator s seat and loader controls mounted on the truck chassis instead of over the cab. Figure 7. Workers prepare to unload trimmings from a power loader into a truck. (Photo courtesy Denver Forestry Section.) 8

9 Figure 9. A chipper and hauler truck are used at a trimming operation. (Photo courtesy Denver Forestry Section.) Whenever brush extends more than 4 feet beyond the end of the truck bed, red flags or other legally required warning devices should be placed on the ends of the brush. Figure 8. An operator prepares to swing about to unload trimmings. Note: The outriggers have been properly set prior to loading. (Photo courtesy Denver Forestry Section.) 39. The following are important issues when using power loaders: Rollover potential exists with power loaders; safety precautions should be taken. Keep power loaders at least 10 feet from all electrical conductors unless the local power company has been notified. As soon as brush is removed from a tree, it should be hauled away at once or cut up and piled neatly away from traffic. When brush is piled on a truck, it should be tied tightly to the truck bed by a rope lattice, tarpaulin or binding. This will prevent the brush from blocking visibility, scraping against cars in traffic, striking pedestrians or blowing off and falling onto streets during transport. The width of a load must conform to local or state ordinances and codes. Note: Workers should never be allowed to ride on top of a load of brush. Chippers 40. Chippers are mechanical devices with openings where brush and branches are fed into rotating knife blades. This machine chips up the material and blows it into a metal-enclosed or canvas-covered truck (Figure 9). This method eliminates the hazards of bulky loads and brush burning. The following are important safety considerations when working with chippers: When attaching a chipper to the hitch at the rear of a truck, install safety chains, coupling the chipper to the truck. Enough slack should be left in the chains to allow the truck to turn at sharp angles. These chains should not drag and trail on the pavement because they could catch on obstructions and upset the equipment. Red flags or other legally required warning devices are recommended at the rear of a chipper. State or provincial laws and codes should be reviewed and followed to prevent violations and penalties. 9

10 Figure 10. A properly hitched coupling (with locking key) is ready for operation. (Photo courtesy Denver Forestry Section.) Check the hitching device and coupling safety chains regularly, especially on long hauls from job to job, to prevent them from becoming too loose or separating (Figure 10). When parking trucks with attached chippers, give particular attention to the location of the equipment chute opening and surrounding work. First consider the traffic pattern keep the equipment from projecting or blocking the flow of vehicles. When parking along a curb, pull the equipment far enough beyond the street intersection to prevent blind spots in any direction for regular traffic. Whenever a chipper is being operated, protect the work area by cones or barricades. This will protect the workers from interference from traffic and spectators. If a chipper is truck-mounted, with the chute opening on the side, it should be parked along the curb with the chute feed facing the curb. Workers then can stand on the parkways, out of the traffic flow and feed the chute. Note: Workers should never attempt to make repairs or adjustments to a chipping unit while it is in motion. They should shut off the ignition switch, remove the key and disengage the clutch. On some models, it might be necessary to install additional lockout devices, using a padlock. Whenever this equipment is left alone, such as during lunch periods, lock out all starting controls and remove the ignition key. If the chipper is left parked, unattended, and uncoupled from the chipper truck, properly chock the chipper unit wheels to prevent it from rolling away. Whenever cutting blades on a chipping unit are changed or adjusted. Properly tighten the lock bolts on the blades to prevent separation of the blades during operation. A follow-up inspection of all lock-bolt work is recommended before chipping units are restarted. On Allen-head lock bolts, use only well-conditioned, properly sized Allen wrenches to assure adequate tightening of bolts, without slipping and consequent hand injuries. Replace lock bolts with stripping heads immediately. To protect fingers, hands, and arms from injury during work on chipper blades and lock bolts, place a portable blade guard over the cutting edge. Never engage the clutch on shut down chipper units to act as a brake on the blade drum while removing, installing or tightening lock bolts. Instead, use a manual locking device at access points provided on the chipper. Make daily checks on the tightness of the locking bolts that hold the cutter blades before starting a unit; then run a test for a few minutes. Operators should wear loose-fitting gloves and eye protection, such as safety goggles or face shields, while feeding a unit. Workers located close to the operation also should wear hand and eye protection. Workers should not attempt to feed small, short pieces of brush into a chute by hand. Instead they should use a longer piece of brush as a pusher. If a large branch becomes wedged in a chute, the chipper should be stopped and the wedged piece removed by hand. 10

11 Note: Before removing any wedged pieces, another worker should stand by the controls while the piece is being removed to avoid inadvertent starts. The removed piece should be cut smaller by hand before returning it to the chipper. Instruct workers never to throw sweepings or other foreign materials, such as stones or nails, into a chipper. These materials can be thrown back into the face of an operator or damage the cutting blades, causing them to break. Do not allow anyone in a truck or in front of an exhaust chute while a unit is running. A blast of wooden chips could blow out of the exhaust chute and into the bystander s face, causing serious injury. OTHER CONSIDERATIONS Electric lines 41. Never directly or indirectly touch any communication wires and cables. Consider them energized with potentially fatal voltage. Workers should observe the recommended minimum working distances from energized conductors (Table I). 42. There may be laws or ordinances pertaining to the clear space work area. Professional line-clearing contractors are more likely to be able to work safely with tools immediately adjacent to energized conductors. When securing themselves, they should make certain they will not swing or fall into the danger zone. 43. Before climbing, entering or working around any tree, the worker and supervisor should make close inspection to determine whether an electrical conductor passes through the tree or within reaching distance of the worker. Assign only a qualified line-clearance tree worker or a qualified line-clearance tree trainee to the work if it is found that an electrical hazard exists. Place a trainee under direct supervision of qualified personnel. 44. Use pole saws and pruners with dry wooden poles and no metal parts to make cuts. Make cuts at the point farthest from conductors. 45. If a limb overhangs a wire and can be reached easily from a ladder, tower truck or Table I: Minimum working distances from energized conductors for line-clearance tree trimmers and trainees Voltage Range (phase to phase)(kv) Minimum Working Distance 2.1 to ft 0 in. (0.6 m) 15.1 to ft 4 in. (0.7 m) 35.1 to ft 6 in. (0.75 m) 46.1 to ft 0 in. (0.9 m) 72.6 to ft 4 in. (1.0 m) to ft 6 in. (1.05 m) to ft 8 in. (1.1 m) to ft 0 in. (1.5 m) to ft 0 in. (2.1 m) to ft 0 in. (3.35 m) to ft 0 in. (4.55 m) 11

12 the tree itself, a supervisor should have a qualified lineman cover the wire with flexible, insulated, protective equipment, if the voltage permits. If the wire is between spans or towers, the local utility company should be asked either to move the line or de-energize it. It is possible to safely remove overhangs between poles with electric lines energized. 46. Only qualified workers should handle fallen or broken wires. Dangerous areas should be roped off or barricaded, the public utility company should be notified and a watchman should be stationed to keep the public away until a line crew arrives. First aid 47. An approved first aid kit, adequately stocked and maintained, should be available to workers at all tree-trimming operations. All workers should be instructed in how to use first aid materials. All workers should be instructed in how to identify and prevent exposures and problems relating to common poisonous plants such as poison ivy, poison oak and poison sumac. 48. All workers should know how to perform cardiopulmonary resuscitation and should undergo frequent refresher courses. When the victim is located in a densely foliated tree that might hinder immediate access, the treetop method of resuscitation should be applied immediately. Treetop resuscitation is the same as the line worker s pole-top method (Figure 11). During this time, openings can be made in the tree by cutting portions or pulling apart branches with ropes. The victim should be lowered through these cleared spaces to the ground, and cardiopulmonary resuscitation should be administered immediately. Where there are no tree obstructions, the victim should be lowered directly to the ground on a blanket, and CPR should be applied immediately (Figure 12). 49. Tree-trimming personnel should be familiar with techniques of rescue from aerial and live-line wires. Figure 11. This pole-top procedure for mouth-tomouth resuscitation can be used for a treetop rescue as well. Figure 12. One man applies resuscitation while another assists with external cardiac massage. 12

13 Felling trees 50. Felling trees requires precise planning and an exact understanding by each crew member of procedures to be followed throughout a felling operation. Planning factors should include the following: Tree height Wood soundness Lean direction Ground slope Tree species Treetop weight Wind direction Dead limbs or stubs that may break off and fall during operations Proximity to other trees, structures and wires Vehicular or pedestrian access problems Positioning of equipment and workers during an operation Type and number of specially qualified workers needed Mechanized and other special equipment needed Required personal protective equipment 51. When felling trees over 10 inches in diameter, a notch and backcut should be used. The depth of penetration of the notch should be about one-third the diameter of the tree. The backcut should be made higher than the point or apex of the notch to prevent kickback. 52. If a tree is to be felled near overhead wires, the limbs should be stripped high enough to allow it to fall without striking and breaking the wires. 53. No one should work in a tree that might be struck by another tree being felled. Workers felling trees must give ample audible warning signals. They must keep away from the base as the tree begins to fall, to avoid unexpected rolls. They also should stand to one side, preferably behind another tree when felling leaning trees, to avoid dangerous kickbacks. Once the job of felling a tree has begun, it should be completed before workers leave for the day. 54. Large trees can fall sideways, and they should be side-guyed in both directions to prevent accidents and property damage. 55. For head-guying, two ropes should be used one for pulling and the other as an emergency line. The head-guy should be pulled tight before sawing begins in case the treetop breaks. (The treetop will break before the tree starts to fall.) As sawing proceeds, the head-guy and emergency head-guy may require tightening to keep them taut. The emergency head-guy should be kept taut so the fall of the tree can be controlled should the head-guy fail. If the truck used by the crew has a winchline, that can be used instead of one rope. Removal of limbs 56. Removal of large lateral limbs usually requires roping to prevent damage to the tree or other property, and to prevent injury to employees or the public. Limbs that must be lowered, raised or swung to the side are roped using the same method. A heavy limb requires three ropes: butt rope, top rope and guide rope (Figure 13). 57. The butt rope is passed through a crotch above the limb to be removed, and one end is secured to the limb near the point where the saw cut is to be made. The other end of the rope is tied to a tree, pole or other firm support to hold the limb until it is ready to be lowered. 58. The top rope is passed through a different crotch, whenever possible above the limb to be removed, and one end is secured near the outer end of the limb. The other end of the rope is tied to a tree or pole until the limb is ready to be lowered. Where a truck is available, the rope can run through a snatch block at the base of a tree 13

14 of the top and butt ropes. 62. If no limb or other tree is available for crotching, the butt rope should be wrapped around a lower stub or passed through a snatch block and lashed to the trunk at a point below the cut. Note: Under no condition should partially sawed limbs be allowed to remain in the tree overnight or after workers leave a worksite even if the job is not completed. Figure 13. This is an example of the proper methodology for using a guide rope, top rope and butt rope to remove and lower large lateral limbs. and be tied to the frame of the truck for raising or lowering operations. 59. The guide rope is fastened near the end of the limb to aid in pulling it around and guiding it past other limbs or obstructions during the lowering process. 60. With the ropes secured in place, a preliminary saw cut should be made at least 2 feet from the trunk. When the cut is deep enough to permit the worker on the ground to pull on the rope and break the limb, the worker in the tree should move to a safe position where the limb being removed cannot kick back and strike. This position should never be under the point where the ropes are crotched. 61. Workers on the ground should use a guide rope to swing the limb to the desired position, and then lower the limb by means Brush removal 63. Members of a crew who handle brush should be warned to watch the ends of the brush to avoid striking another worker on the head or in the face when the brush is pulled from the tree by pruners. Workers who handle brush should wear safety hats and goggles or other suitable eye protection. They should avoid working under trees that are being trimmed. Brush disposal 64. Brush should be disposed of in accordance with waste disposal regulations. Often, local ordinances will govern the burning of brush. If the brush is to be burned near the job areas, pile it in a place away from wires, cables, fences, poles or buildings. Fire protection equipment should be provided. Extinguish or guard fires before a crew leaves for any reason, such as lunch, breaks, or at the end of the workday. Unload brush at a safe distance and away from fires. The burning area should be large enough for several piles to be burned at the same time, with enough room for unloading at burned-out spots. Never back up a truck to a fire for unloading. If the brush on the truck should catch fire, it might ignite the gasoline tank or other flammable materials. 14

15 Fire hazards 65. Workers should be alert for the following fire hazards and take the recommended precautions while working around treetrimming equipment: Never park in high weeds or grass because the exhaust pipe could ignite them and cause a fire. Clean chips from the motor, especially around the exhaust manifold, to prevent fires. Never leave chips in a truck over a weekend because they can dry out and become a fire hazard. Never dump chips into street gutters or on private property. Children may set fire to them. Dispose of collected wood chips in a local dump, or give them to property owners or farmers for cattle bedding. Public safety 66. Before tree-trimming or removal operations begin, pedestrians and drivers should be warned with red flags and danger signs set up on sidewalks and on the street in the vicinity of where the work is to be done. Block off hazardous areas with barricades or ropes. 67. When traffic is congested, station a worker with a red flag to direct those who must step into the street to go around the site of an operation. If necessary, call local authorities to close traffic lanes during operations. Provide warning lights in obscure places or in dark areas. 68. Limbs and other brush should be thrown or lowered by rope away from the street side and off the sidewalk if possible. Otherwise, have one worker remove the brush from the sidewalk as soon as possible. Keep tools and equipment off sidewalks and streets. Keep ropes coiled to prevent tripping hazards. Workers should use hand lines to raise or lower tools and materials and make sure the public is clear of the area before they do so. Environmental problems 69. Poisonous plants will adversely affect many persons on contact. In areas where poison ivy, poison sumac and poison oak are growing, workers should be able to recognize each and take special care to avoid contact with them. They also should avoid the smoke generated from burning such plants. The smoke carries oil from the plant, and contact with the skin may result in a skin eruption or dermatitis. At the first sign of irritation, workers should report to their supervisor and obtain immediate medical attention. 70. Some workers are allergic to the fine dust or fuzzy substances given off from the underside of the sycamore leaf. Such workers should wear dust respirators when trimming trees during the summer months. (To avoid this hazard, sycamores should be trimmed during the winter.) 71. Workers should be cautious when working in or around honey locust and black locust trees because some have thorns that can cause cuts and scratches and initiate secondary infections. 72. Immediately upon approach of an electrical storm, workers should be ordered down from trees. They should seek shelter in the following manner: If possible, workers should sit in an automobile or truck. These vehicles should not be parked in an open space on top of a relatively bare hill where it is the highest object in the immediate vicinity. Workers should keep away from wires, especially wire fences. Workers should avoid taking shelter under a tree. 73. Except in emergency circumstances, trees should not be climbed or worked 15

16 during wet or icy weather. It is extremely difficult to get a good foot or hand hold on slippery bark, and knots in climbing ropes are likely to slip if a rope is wet or frozen. Sources of information American National Standards Institute, 1819 L Street, 6 th Floor, Washington, DC Practice for Occupational and Educational Eye and Face Protection, ANSI Z87.1. Safety Requirements for Portable Wood Ladders, ANSI A Safety Requirements for Tree Care Operations Pruning, Trimming, Repairing, Maintaining, and Removing Trees, and for Cutting Brush, ANSI Z Acknowledgment This data sheet was prepared by the Public Utilities Division of the National Safety Council, 1121 Spring Lake Drive, Itasca, IL Copyright 2007 National Safety Council. All rights reserved. Although the information and recommendations contained in this publication have been compiled from sources believed to be reliable, the National Safety Council makes no guarantee as to, and assumes no responsibility for, the correctness, sufficiency or completeness of such information or recommendations. Other or additional safety measures may be required under particular circumstances. 16