38 Occupational Outlook Quarterly ● Spring 2001

The eucalyptus trees in Phoenix,

Arizona, were dying fast. And it was

Jeff Walton’s job as an arborist to find

out why.

After examining the trees and

researching plant diseases, he identified the culprit: the eucalyptuses were

infested with a fungus. Jeff injected the

trees with a specially formulated

fungicide and prescribed a watering

regimen. The trees survived, together

with the shade they gave the Arizona

desert.

“Arborists are really tree doctors,”

says Jeff. As tree doctors, arborists

diagnose and treat tree diseases,

nutrient deficiencies, and structural

problems. “Trees are living organisms,”

he says. “They are constantly growing

and changing.”

Working as a consultant for a tree

care company, Jeff helps people

understand and care for their trees.

“One of the things I like most is

education—explaining how the

anatomy of a tree works, how diseases

affect trees, and how a tree’s immune

system functions,” he says. “I like

convincing people that their trees are

living and growing and need to be kept

healthy.”

Jeff drives to customers’ houses

by Olivia Crosby

and examines their trees. He checks

the bark for signs of decay or damage.

Then, he checks the leaves for abnormal changes in color or texture.

Sometimes, he removes dirt at the

base of the tree to examine the root

structure. Like most arborists, he uses

binoculars to inspect the upper

branches of a tree or climbs into the

canopy of branches for a closer look.

When an illness is hard to diagnose,

Jeff takes tissue samples, snipping off

leaves or small branches. He sends the

samples to arborist specialists for

analysis.

If Jeff finds viruses, bacteria, fungi,

or harmful insects, he recommends a

course of action. He might spray the

tree with pesticide or fungicide or

inject medicine into its bark. After

treatment, he might prescribe a special

watering or fertilizer regimen, as he

did in the case of the dying Arizona

eucalyptuses.

Often, he cuts diseased or infested

branches off the tree to save the

others, a process called pruning. He

also prunes branches that rub together and those that are not well

supported by the rest of the tree.

Pruning a tree correctly takes skill.

Arborists climb onto a tree’s branches

using ropes and hanging seats called

climbing saddles. They carefully remove

branches with chainsaws, shears, and

tiny clippers. If a branch is diseased,

arborists sometimes dip their tools in

disinfectant before cutting another

branch to prevent the spread of

infection.

Jeff, like all arborists, uses mathematics to analyze a tree’s structure

before he decides which branches to

cut. “We use equations to decide how

structurally sound a tree is,” says Jeff.

“We measure the tree’s circumference, and we can figure out a tree’s

height without climbing it.” Some

arborists use computer programs to

calculate the forces and weights within

a tree.

A tree’s structure can be a matter

of life and death for the people who

live near it. Weak, diseased, or unsupported branches can crack and fall,

crushing cars, houses, or people

beneath them.

Despite all the treatments available,

some trees cannot be saved. “People

don’t look up at their trees often

enough,” Jeff explains. “It’s not until a

tree is screaming for attention that

most people notice there’s a problem.

We can’t always save trees that are

already very sick.”

Removing a dead or dying tree can

be tricky. To remove a poplar tree

from a customer’s yard, for example,

Jeff needs a climbing saddle, ropes,

chains, and a 200-ton crane—along

Olivia Crosby is a contributing editor to the OOQ,

(202) 691-5716.

You’re a what?
Occupational Outlook Quarterly ● Spring 2001 39

with the help of other arborists and

landscape workers.

Tree care and removal is dangerous

work. While balancing in climbing

saddles high above the ground, most

arborists use chainsaws to cut

branches. Avoiding injuries takes

practice and training.

Even without a traumatic injury,

arbor care can be strenuous. “You’re

carrying heavy wood,” Jeff says of

downed trees and branches. “This

work can be hard on your back.”

Not every arborist’s job is as

physically demanding, though. Some

arborists help clients decide which

trees to buy and where to plant them.

Conditions vary from region to region

and even from one part of a backyard

to another. Arborists understand

which trees will thrive in which

environment.

Other arborists preserve trees

growing on construction sites. They

mark where roots begin and design

temporary enclosures to protect them

during building. An arborist can do

this kind of work without ever

climbing a tree.

The Bureau of Labor Statistics does

not collect employment data on

arborists. But according to the

International Society of Arboriculture,

there are more than 12,000 certified

arborists in the United States and

thousands more who aren’t certified.

Most arborists work for tree care

companies. Others work for State and

local governments, caring for trees on

roadsides and other public properties.

And some work for themselves as

private consultants.

Earnings increase with experience

and responsibility. Ground workers,

who chop and carry away fallen

branches, earned an average of $9.50

an hour in 1999, according to a survey

by the National Arborist Association.

Climbers earned an hourly average of

$13, and crew leaders averaged $15.

Arborists who diagnose and treat

specialty trees can earn more.

Still, like most arborists, Jeff didn’t

choose his career for the money—

although he says the field can be

financially rewarding to people who

are good at their jobs.

Drawn to his work by a love of the

outdoors, Jeff changed his career path to

work with nature. “I was in college

studying for a business degree, but at

the same time I was working at a

landscaping company,” he says. “I realized

that with a business degree I might end

up in a cubicle, watching the outdoors

from a little window. If I worked in

landscaping, I could be outside all day in

the natural environment.” He stopped

studying business and started working

full time at a plant nursery.

Over time, Jeff’s interest in trees

grew. He took classes in tree anatomy,

physiology, and disease treatment

while working at the plant nursery.

After gaining more than 3 years of

field experience, he took the Society’s

certification exam and became a

certified arborist. He still takes classes

to maintain his certification and to

keep up with scientific advances in

tree care. “We need people who are

curious. There are always new things

to learn about trees,” he says.

Some arborists combine

coursework with experience, as Jeff

did, to enter the occupation. Others

enroll in formal degree programs,

earning an associate or bachelor’s

degree in horticulture, botany, or

forestry. Still others continue their

education, earning a master’s or

doctoral degree. Those with advanced

degrees sometimes become researchers or expert witnesses in court cases

involving trees.

Hands-on tree work is still the kind

of arbor care Jeff likes best. “It’s an

honor to work with these majestic

living organisms,” he says. “To be able

to understand what makes them

strong and healthy is amazing.”