MIFACE Investigation Report #09MI163 

Subject: Tree Trimmer Working in Tree Died When a Tree Branch 

Supporting Rigging Rope Broke Below the Crotch and Struck His Head 

Summary 

In the fall of 2009, a male selfemployed tree trimmer in his 50s 

died while he was removing a 

dead tree from a residential yard. 

The decedent was working 

approximately 30 to 40 feet above 

ground removing branches using a 

saddle belt, safety rope, and 

branch (natural) crotch rigging 

with a 3/4-inch rope. He was 

injured when a tree branch that 

had been used to support a rigging 

rope broke below the crotch and 

struck his head. The force of the 

blow from the falling branch 

rendered the decedent unconscious 

and knocked him from the tree. 

Emergency responders arrived three minutes after the call for assistance. The decedent 

hung from his safety harness for approximately eight minutes until emergency responders 

were able to support his body using a utility bucket truck. The emergency responders 

placed him on a backboard and then lowered him to the ground via the fire department 

ladder truck. He was driven by ambulance to a staging area and flown by helicopter to a 

nearby hospital where he died from his injuries two days later. 

Factors that may have contributed to this fatal injury include: 

• Tree branch anchoring point did not hold the decedent’s weight. 

• Rigging method did not support the branch removal activity. 

• Decedent’s head was not protected from falling objects. 

• Ground worker inexperience in rigging methods. 

RECOMMENDATIONS 

• Tree trimmers/fellers should be properly trained in assessing and identifying 

hazardous trees. 

• Using the information gained in the assessment, appropriate rigging techniques 

should be used to ensure a dynamic rigging system is in place to minimize friction 

and shock load during trimming operations. 

• Tree trimmers/fellers should wear appropriate personal protective equipment 

during tree trimming/felling operations. 

Figure 1. Incident scene showing aerial bucket 

and ladder and portable ladder against tree 

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• Tree trimming employers should ensure ground workers have the training and 

experience necessary to perform work with rigging ropes and are trained to 

perform an aerial rescue if an emergency arises. 

• The State of Michigan should require registration or licensure of individuals 

involved in tree care/tree trimming operations. Registration/licensure 

requirements should include an arborist accreditation by an organization such as 

the Tree Care Industry Association (TCIA) or the International Society of 

Arboriculture (ISA). 

MIFACE also recommends that emergency responders wear required fall 

protection equipment when working from an elevated working surface, such as an 

elevated bucket or ladder. 

INTRODUCTION 

In the fall of 2009, a male self-employed tree trimmer in his 50s died while he was 

removing a dead tree from a residential yard. MIFACE learned of this death through a 

newspaper article. In November 2010, MIFACE conducted two site visits separately 

interviewing the decedent’s sons and his spouse at the decedent’s home. In April 2011, 

MIFACE conducted a site visit at the incident location and spoke with the chief of the 

responding fire department and the homeowner who contracted the decedent to remove 

the tree. In March 2012, MIFACE interviewed a certified arborist to gather information 

about the root causes of this incident and to assist in the development of prevention 

recommendations. Pictures used in Figures 1, 2, 3 and 5 of this report are courtesy of the 

responding fire department. The picture used in Figure 4 was taken with the permission 

of the family at the decedent’s home. Pictures have been modified to preserve 

confidentiality. 

Employer 

The decedent was the owner of the company and had been in business for 17 years. He 

performed all of the elevated climbing and cutting and was the only individual who felled 

trees. He was a self-taught tree trimmer with 35 years of experience and performed 

residential tree trimming/felling and was also contracted by logging firms to fell trees. 

When he was 15 years old, he worked in this father’s tree cutting business, and later 

worked with another individual who performed tree work. 

His work schedule and number of employees were based on weather and time of year. 

Summer tended to be the busiest time of year, but at times, winter weather caused 

extensive tree damage and he would be busy in clean-up work. During the 

spring/summer/fall months the decedent had three to four employees, two of whom were 

his sons. During the winter months, the decedent would work with one of his sons. 

His sons had been working for him for over 10 years. The decedent normally worked for 

six hours each day, 4-1/2 days/week. The decedent was routinely home by 4:00 p.m. His 

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sons indicated he was familiar with all tree types and sizes. His family indicated he had 

fallen from a tree and had been cut by a saw on several occasions. 

Written Safety Program and Training 

The decedent did not have a written safety program nor formalized training. His two sons 

both of whom worked with him indicated that the decedent verbally communicated 

hazards and safety instructions. One of his sons was responsible for training new 

employees. The decedent was not a certified arborist or member of an arborist 

association. His sons indicated the decedent did read some Michigan State University 

Extension publications about tree health. 

Both sons indicated that if, during a job, the instructions were unclear or if a worker did 

not fully understand the job assignment or cutting procedure, the decedent would stop the 

job and explain the procedure a second time. The individuals hired by the firm were 

mostly experienced tree cutters, but the owner still provided any necessary answers to 

questions. His sons indicated the decedent encouraged anyone to ask him questions. 

While at the job site, the decedent designated who would be the ground workers and their 

work tasks. 

There was a self-imposed disciplinary policy, but no written policy. Behaviors were 

corrected at the job site. Mostly, family and friends were tapped as workers and discipline 

was not necessary. 

The decedent provided on-the-job training including chain saw training to individuals 

who used a chain saw. The decedent had reviewed the MSU Extension website and 

received MSU Extension publications regarding tree types and issues regarding these tree 

types. 

His sons indicated the decedent wore safety glasses, but did not usually wear a hard hat 

or goggles due to fogging and sweating issues. His sons mentioned that when climbing, 

the hard hat falls off one’s head and therefore would not provide head protection. This 

distinction was made by family members compared to trimmers working from a bucket 

truck. 

Work Process 

The decedent did not free climb unless it was required he do so. Each day, prior to a job, 

the decedent checked his rigging ropes, climbing equipment, and tree cutting equipment 

for frays, tears, and wearing out issues. His sons indicated he always kept his saws sharp 

and performed routine maintenance on all cutting equipment owned. 

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INVESTIGATION 

The decedent had been contracted by a 

homeowner to cut down a dead silver 

maple tree in the front yard. The tree 

had died during the past year. The 

decedent’s sons both remembered the 

tree was alive the previous year when 

they had cut down a tree in a 

neighboring yard. The tree branches 

were oriented over the home, the 

driveway and the sidewalk. The 

decedent was working with both of his 

sons on the day of the incident. On the 

first day of the work, the decedent 

climbed the tree, and he and his two 

sons “brushed out” the tree, removing 

branches that were two to three inches 

in diameter, leaving the larger limbs. The smaller limbs were placed on a trailer to be 

hauled away. The trailer was parked on a street with a low volume of traffic. The crew 

did not place traffic cones in the roadway to warn oncoming traffic nor were spotters 

used to keep traffic/pedestrians away from the trimming site. The crew had almost 

completed the brushing operation on Day 1. 

The incident occurred on the second day of work. The crew arrived at the site between 

8:30 a.m. -9:00 a.m. A couple of hours later, the brushing operation was complete. The 

decedent donned his climbing saddle and secured his safety rope and climbed the tree to 

place the rigging rope. The type of rope used was unknown. From pictures taken at the 

scene by the fire department, the construction of the rope appeared to be a three-strand 

rope. The sons indicated the 

decedent used a 3/4-inch diameter 

rope. It is unclear how many 

crotches were utilized. The crotch 

shape(s) was unknown. According 

to his sons, the 3/4-inch rigging 

rope had been wrapped around the 

base of the tree; it is unknown how 

many wraps had been made. One 

son was responsible to handle the 

end of the rigging rope and control 

the limb descent after the limb was 

cut and the other son was 

responsible for clean-up, traffic 

Figure 3. Incident scene after rescue showing control, etc. 

location of ladder truck, ladder leaning against 

The incident occurred while the tree and tree architecture 

Figure 2. Overview of incident scene 

showing tree architecture and position of 

bucket truck and aerial ladder truck 

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crew was “pulling wood”, i.e., cutting 2- to 5-inch diameter branches and lowering them 

to the ground and piling them out of the way to pick up later. 

On this day, the decedent had 

promised to be home early to paint a 

bedroom. The decedent climbed up 

the tree approximately 30 to 40 feet 

to begin cutting the branch located 

over the driveway. It appears that the 

decedent used the same type of rope 

for both climbing and rigging – a 

three-strand, 3/4-inch manila. It is 

unknown if the rigging rope and the 

climbing rope were one in the same. 

After positioning the rigging rope, he 

began to cut the remaining branches. 

Based on pictures, several branches 

had been cut and lowered prior to the 

incident. His work position while cutting the branch involved in the incident is unknown. 

The type of tie (butt or tip) at the limb is unknown. At the time of the incident, he had cut 

an approximately six to eight foot section of a 16-inch diameter limb with an estimated 

weight of 300-400 pounds. When the cut was completed, it appears that the dynamic 

forces caused by the falling limb overloaded the branch/crotch, causing the branch to 

break and propel toward the decedent, striking the back of his head. His sons heard a 

“crack” and the rigging rope went slack. 

A neighbor who had been watching the felling activity called for emergency response. 

The police department arrived first and then called for the fire department and ambulance 

and helicopter. 

When the fire department received the dispatch call, they contacted the city, which had its 

own electrical cooperative for a bucket truck, and a nearby fire department for a ladder 

truck. Applicable city employees have been trained and work under a unified command 

system. 

While waiting for the bucket truck and ladder truck to arrive, the fire department cleared 

the area of bystanders and made room for the bucket to pull up to the tree. The fire 

department placed a 24-foot extension ladder against the tree on the request of a neighbor 

to determine if the decedent could be reached. The fire department placed the ladder 

under the victim but the ladder did not come close to reaching him. 

The decedent was hanging in the harness facing upward and his head and arms hanging 

back. His chain saw was hanging and was tied off. The bucket truck arrived 

approximately five minutes after the fire department arrival. When the bucket truck 

arrived the fire chief told the driver where to position the truck to permit access to the 

decedent. The city workers entered the bucket and began to raise the bucket to begin 

Figure 4. Climbing saddle worn by decedent 

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emergency response operations. The Fire Chief determined that trained fire department 

personnel, a paramedic and an EMT should effect the rescue. The paramedic and EMT 

got into the bucket and raised the bucket into position to provide emergency aid to the 

decedent. The fire department personnel, in their haste to begin emergency response 

procedures, did not wear a safety harness and did not tie off to the bucket. Upon reaching 

the decedent, they positioned him to the edge of the bucket to take the weight off of his 

body and lifted his head in an attempt to open an airway. The ladder truck arrived and 

was positioned in a neighbor’s yard. The ladder was raised next to the bucket truck and 

the decedent was cut away from his harness, placed on a stretcher, and then lowered to 

the ground using the ladder. He was placed in an ambulance and taken to the staging area 

for helicopter transport to a local hospital. He died two days later from complications of 

the head injury sustained when the branch struck his head. 

A neighbor, who was watching the decedent and his crew work, told the fire chief who 

was the incident commander on the ground that she heard the decedent state “you will get 

somebody hurt if you don’t keep tension on the rope”. It is unknown when (and if) this 

statement was made (during the cutting of other limbs or just prior to the incident). 

One of his sons returned to the incident site four days later to clean the yard of the brush 

and limbs remaining on the ground. While there, he found a jagged-edged piece of a tree 

limb with a crotch that he thought was from the branch that had broke and struck his 

father’s head. 

CAUSE OF DEATH 

The cause of death as listed on the death certificate was left subdural hemorrhage due to 

or as a consequence of craniocerebral trauma. An autopsy was not performed. 

Contributing Factors 

• Tree branch anchoring point did not hold the decedent’s weight. 

• Rigging method did not support the branch removal activity. 

• Decedent’s head was not protected from falling objects. 

• Ground worker inexperience in rigging methods 

RECOMMENDATIONS/DISCUSSION 

• Tree trimmers/fellers should be properly trained in assessing and identifying 

hazardous trees. 

The American National Standards for Arboricultural Operations – Safety Requirements 

(ANSI Z133.1-2006), section 8.4 Rigging, details many requirements of the arborist in 

regards to rigging operations. Included in these requirements are the following: 

 Arborists performing rigging operations shall inspect trees for their integrity to 

determine whether the trees have any visible defects that could affect the 

operation. If it is determined that the tree poses a risk of failure due to the forces 

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and strains that will be created by the design of the rigging operation, an alternate 

plan shall be used. 

 Rigging points shall be assessed for their structural integrity by a qualified 

arborist. The rigging plan and the tree shall be considered relative to the forces 

being applied to any part of the tree, including branch attachments and anchoring 

roots, before a rigging point is chosen and established. 

 Arborists performing rigging operations shall be educated to understand and 

trained to estimate the potential forces at any point in the rigging system being 

used. The system components shall comply with working-load limits relative to 

the operation and the maximum potential forces. 

 Careful consideration shall be given to the potential forces resulting from the 

specific influences of rope angles as well as the number of lines and/or line parts 

that act on any rigging point. 

The decedent had extensive tree trimming/felling experience, but, the extent of his 

education and training and understanding of how to assess the structural integrity and 

potential forces placed on a tree during a rigging operation was unknown. Also unknown 

was the thoroughness of the decedent’s structural evaluation of the dead tree, including 

the limbs and the crotches used to support the rigging. 

The Tree Care Industry Association (TCIA) Best Practices for Rigging in Arboriculture 

states in Chapter 1: “When done incorrectly, rigging can be one of the riskiest operations 

there is in tree care. One of the biggest opportunities for error is misjudging the tree. The 

safety and efficiency of the rigging operation is directly dependent on the condition and 

stability of the rigging tree(s). An accurate examination of the tree is necessary in order to 

determine the tree strength relative to the rigging loads expected on it. The qualified 

arborist/rigger must have specialized training to evaluate the tree for hidden as well as 

obvious defects that may affect the rigging procedure”. 

MIFACE recommends that arborists become certified and when involved in rigging 

operation(s) attend training and participate in professional organizations to improve their 

skills and to raise their awareness of new equipment and trends in tree care and safety. 

Training programs should be approved by organizations such as the National Arborist 

Association, the International Arborist Association and Tree Care Industry Association. 

Arborists should also be aware of MIOSHA regulations and American National 

Standards Institutes, Inc. (ANSI) standards. 

• Using the information gained in the assessment, rigging techniques should be 

selected to ensure a dynamic rigging system is in place to minimize friction and 

shock load during trimming operations. 

The decedent had used the natural crotch rigging system to successfully lower several 

loads prior to the incident load. When the incident occurred, the decedent had cut a 

bigger piece from the branch than he had earlier in the day. The branch used for rigging 

broke below the crotch when the larger limb was cut. One of the possible factors 

contributing to the branch breaking was the design of the rigging system, which may 

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have contributed to increased friction and shock load placed on the branch/crotch when 

the incident limb was cut and fell free from the tree. Issues such as the crotch shape (“U” 

shaped versus “V” shaped), rigging branch diameter, the rigging rope angles and length, 

rigging point distance from the number of rope wraps around the trunk, and the ability of 

the ground man to “let it run” are all unknowns. 

Designing a rigging system to minimize friction, reduce forces on the tree, and 

positioning the rigging points to permit more rigging rope in the system to reduce the 

shock load is desirable. The work practice of establishing false crotches by use of 

arborist’s blocks and pulleys, and a friction device, such as a “Port-a-Wrap III” or a 

board-type lowering device, such as the “Hobbs Lowering Device” provide more 

consistent friction and minimizes rope wear. The advantages of using pulleys rather than 

natural crotches are: 1) reduces friction and forces on branches; 2) direction of the load 

over the landing zone. 

Several resources have been developed to assist riggers in selecting the appropriate 

rigging techniques involved in tree trimming/removal. The International Society of 

Arboriculture (ISA) Tree Climbers Guide, 3rd Edition and the Tree Care Industry 

Association (TCIA) Best Practices for Rigging in Arboriculture, provide guidance to 

operators during rigging operations to remove a section of a tree. 

• Tree trimmers/fellers should wear appropriate personal protective equipment 

during tree trimming/felling operations. 

Although the decedent was self-employed and not governed by MIOSHA Safety and 

Health Standards, all self-employed individuals should be familiar with and follow these 

standards minimize injury and/or illness. MIOSHA General Industry Safety Standard, 

Part 53 - Tree Trimming and Removal mandates the use of safety glasses and hard hats 

for all workers at the tree trimming operation. The International Society of Arboriculture 

(ISA) Tree Climbers Guide, 3rd Edition, references the use of a Type II hard hat and eye 

protection, such as goggles and face shield to further protect the face. Additionally, 

MIFACE recommends hearing protection, as the decibel level of chain saws would 

require only 15 minutes of use before the TWA for noise has been reached. 

Wearing all appropriate personal protective equipment should be practiced by all tree 

trimmers and ground personnel at the site. Although it is unknown if the decedent would 

have survived the head strike by the falling branch if he had been wearing a hard hat, 

wearing appropriate head protection could have lessened the impact of the limb and the 

fatal injury may have been avoided. The family members indicated that the decedent did 

not wear a hard hat because the hard hat would fall off his head while working. Chin 

straps that attach to the hard hat’s suspension are available for many models. Chin straps 

can prevent hard hats from falling from or bumped off a worker’s head, or dislodged due 

to high winds or awkward work positions (e.g. bent over). 

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• Tree trimming employers should ensure ground workers have the training and 

experience necessary to perform work with rigging ropes and are trained to 

perform an aerial rescue if an emergency arises. 

Ground workers are an essential component of a rigging operation. Ground workers assist 

in setting up friction devices, run lines, detach ropes and send equipment and lines up to 

the climber, and “running the ropes”. One of the emergency responders was told by a 

neighbor that the decedent stated “you will get somebody hurt if you don’t keep tension 

on the rope”. Once a piece is cut and begins to fall, it will create a dynamic load on the 

rigging line. An experienced ground person can minimize this effect by gradually letting 

out more rigging line into the system before bringing the piece to a stop (“letting it run”). 

The comment, as overheard by the neighbor, may indicate that the ground person did not 

have enough experience to “let it run” when the larger limb was cut, causing an increased 

load on the line and the crotch. 

The ISA recommends that all crew members receive training in first aid and 

cardiopulmonary resuscitation (CPR). Additionally, ISA recommends that anytime a 

climber is in a tree, there should be a second worker on the site who is capable of 

performing an aerial rescue. Neither of the ground persons at the site was trained in aerial 

rescue. 

• The State of Michigan should require registration or licensure of individuals 

involved in tree care/tree trimming operations. Registration/licensure 

requirements should include an arborist accreditation by an organization such as 

the Tree Care Industry Association (TCIA) or the International Society of 

Arboriculture (ISA). 

The decedent, although he had many years of experience, was not a certified arborist. 

Certified arborists are familiar with the recommended safe work practices for tree 

removal including trimming, rigging methods, and regulatory requirements. Since 2001, 

in Michigan at least 25 individuals have been killed while performing tree trimming work 

(excluding loggers). Most were not certified arborists. The hazards of tree trimming work 

and the methods to perform tasks safely have been identified by the tree trimming trade 

organizations, such as the TCIA and ISA. To minimize the number of future deaths in 

this profession, tree trimming work should be considered a licensed profession in 

Michigan and as a requirement for the license the individual and/or firm owner should be 

a certified arborist. License monitoring should be delegated to the Michigan Department 

of Licensing and Regulatory Affairs (MDLARA) Licensing Division. 

MIFACE also recommends that emergency responders wear required fall 

protection equipment when working from an elevated working surface, such as an 

elevated bucket or ladder. 

The fire department’s emergency responders were performing their rescue duties from an 

elevated working surface. MIOSHA General Industry Safety Standards, Part 58 – Aerial 

Work Platforms and Part 74 – Firefighting both require workers to utilize fall protection. 

9 
 

 

Part 58 requires the employer to provide, and 

the employee to use, a safety harness that has 

a lanyard which is in compliance with 

Construction Safety Standard Part 45 “Fall 

Protection” and which is affixed to 

attachment points provided and approved by 

the manufacturer if the employee is working 

in a vehicle mounted or boom supported 

elevated work platform. Part 74, Rule 7424 

requires an employee be secured with a safety 

belt if working from an aerial ladder. In their 

haste to provide emergency care, the 

emergency responders did not remember to 

don a safety harness and appropriately tie off, 

thus exposing themselves to a fall injury, 

MIFACE recommends that fire fighters wear a fall protection harness and tie off 

appropriately to minimize the chance of falling and subsequent injury during emergency 

response activities when working from an elevated position, such as in a bucket truck. 

RESOURCES 

MIOSHA standards cited in this report may be found at and downloaded from the 

MIOSHA, Michigan Department of Licensing and Regulatory Affairs (MDLARA) 

website at: www.michigan.gov/mioshastandards. MIOSHA standards are available for a 

fee by writing to: Michigan Department of Licensing and Regulatory Affairs, MIOSHA 

Standards Section, P.O. Box 30643, Lansing, Michigan 48909-8143 or calling (517) 322-

1845. 

• MIOSHA General Industry Safety Standard, Part 54, Tree Trimming 

• MIOSHA General Industry Safety Standard, Part 58, Aerial Work Platforms 

• MIOSHA General Industry Safety Standard, Part 74, Fire Fighting 

• Tree Climbers’ Guide, 3rd Edition. International Society of Arboriculture. P.O. 

Box 3129, Champaign, IL 61826-3129. http://www.isa.arbor.com 

• Best Practices for Rigging in Arboriculture. Tree Care Industry Association. 136 

Harvey Road, Suite 101, Londonderry, NH 03053. http://www.tcia.org 

• Safety Requirements for Arboricultural Operations. American National Standards 

Institute. ANSI Z133.1-2006. 

• California FACE Program Inspection Report #10CA002: Tree Trimmer Dies 

When He Is Crushed by Palm Tree Branches. 

http://www.cdc.gov/niosh/face/stateface/ca/10ca002.html 

• New Jersey FACE Program Inspection Report #96NJ074: Tree Trimmer Killed 

When a Branch to Which He Was Tied Broke and His Lifeline Failed. 

http://www.cdc.gov/niosh/face/stateface/nj/96nj074.html 

• California FACE Program Inspection Report #09CA010: A Tree Trimmer Dies 

When He Falls From a Tree and is Struck By a Limb. 

http://www.cdc.gov/niosh/face/stateface/ca/09CA010.html 

Figure 5. Emergency responders not 

wearing fall protection while elevated 

during rescue 

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Key Words: Tree trimming, Struck by, Rigging system, Arborist, 

MIFACE (Michigan Fatality Assessment and Control Evaluation), Michigan State 

University (MSU) Occupational & Environmental Medicine, 117 West Fee Hall, East 

Lansing, Michigan 48824-1315; http://www.oem.msu.edu. This information is for 

educational purposes only. This MIFACE report becomes public property upon 

publication and may be printed verbatim with credit to MSU. Reprinting cannot be used 

to endorse or advertise a commercial product or company. All rights reserved. MSU is an 

affirmative-action, equal opportunity institution. 7/19/2012 

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