How to Select an Arborist or Tree Service Company

If you need a ladder, you need an arborist.

As Tree Stewards say: If you need a ladder, you need an arborist!

While Tree Stewards do not recommend specific companies, we do provide advice for selecting a good service. Above all, we recommend contacting a certified arborist working with a bonded and insured tree company. You could ask for recommendations from neighborhood list serves only, but not all tree services employ professional arborists or have the bonding you want. You want a certified arborist caring for your trees the same way you want a licensed veterinarian caring for your pet. Here is a step-by-step for selecting and contracting with an arborist:

(1) is the listing of the International Society of Arboriculture (ISA) certified arborist for our region. You click on Accept and are given a choice of states and counties. You can choose either Arlington or Fairfax county since only counties are listed (sorry Alexandria) and up will come more than 50 names of arborists along with the services they provide as well as each one’s advanced trainings. You’ll note most arborists are employed by tree service companies, and they will list services such as pruning, health care, cabling, etc. Others only provide consultation services of assessment, expert witness, pre-construction, etc., and will refer you to other tree service companies for the actual work.  You can find local consulting arborists at Consulting arborists

Select several and call or email describing your need. You want to select an arborist who has experience in your area of need, whether it is construction issues, risk appraisal or getting a healthy tree check-up. Do ask about fees over the phone. A consulting arborist charges for her/his time coming to assess your tree while many tree service arborists do not charge for an initial visit and provide a quote on future work to pay for their time. If you are concerned as to whether your large tree is a risk, but you really don’t want to lose it, then you might feel more comfortable with the advice from a consulting arborist who has no economic interest in promoting additional services.

(2) Schedule meetings in your yard with at least two or more certified arborists the same way you’d ask more than one remodeler to view your home. Certified arborists carry their license on their person, so don’t hesitate to ask to see it. Ask if a certified arborist will be supervising the actual work, and if not, inquire about the training and experience of the work foreman. Use that knowledge as a factor in your decision. If there is a significant difference in suggested treatment of the trees, ask for explanations. Just like physicians, arborists may approach a problem with different strategies but each should be able to explain the rationale. If you do internet research on the recommended services, Tree Stewards recommend using only sites from University Extension Services (ending in “.edu”) or from governmental forestry websites (ending in “.gov”)

Climbers must practice safety first.

Be sure the tree service you use requires tree climbers to practice safety first. Climbers need to be adequately roped to prevent falls.

(3) Reach an agreement on the scope of the work to be performed, obtain a written estimate and ask for proof of insurance. Working on large trees has risks, for the worker high up and any targets on the ground so be sure the company has trained workers, uses safety equipement and carries adequate liability insurance. Ask for referrals and take time to follow-up and make the calls. Always get a second opinion.

(4) When you have selected a tree service, try to schedule the work when you are home and available to meet with the crew prior to the start of the work. Talk with the arborist or the crew chief or foreman who will supervise the work. Be sure to review the scope of the job with the foreman to ensure there are no misunderstandings. If anything concerns you, insist on speaking with the certified arborist who estimated the job.

You want the best service for your trees, and reputable firms do not want dissatisfied customers. Communicate often and well with the company and give it a chance to make corrections if you are not satisfied with the work.

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Champion Dawn Redwood Threatened

In an effort to preserve a unique, mature tree in Arlington, the Williamsburg Civic Association and Arlington Tree Action Group have asked the County Board and county staff to not let the Commonwealth’s Champion Dawn redwood be removed by a builder who intends to subdivide a large lot, tear down the existing house, and build two new six-bedroom houses.

The one-of-a-kind tree species was thought to be extinct until it was found growing in China. It was imported in 1948 and proved a fast-grower with feathery needles it sheds in the fall. Read the civic association’s letter, which notes the tree’s large size and location in the Resource Protection Area (RPA) of a nearby stream.

Arlington’s Urban Forestry Commission joined the debate with a July 6 letter urging the County Board to direct the county manager “to pursue all possible alternatives to protect this magnificent tree and the RPA.”

Some local jurisdictions, such as the District of Columbia, have strong tree-preservation ordinances and impose significant financial penalties for removing a healthy, mature tree. That is not the case in Virginia, where local governments are restricted from enacting ordinances that are more stringent than statutes that govern the Commonwealth. This so-called Dillon Rule thwarts local action on many issues, including enacting more effective tree-preservation controls.

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Mature Trees Are Valuable Trees

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Sign Up Now to Become a Tree Stewards Volunteer

Do you want to help grow and sustain the urban forest? Become a Tree Steward!
Sign up for the 2018-2019 Training Class today—space is limited.

What do Tree Stewards do?
Tree Stewards
Increase public awareness of intrinsic value and beauty of trees
Help in caring for the urban forest and work to increase canopy cover
Educate residents about urban forestry and the care of trees
Involve the community as volunteers in caring for trees

How do I become a Tree Steward?
Take the Tree Stewards Training Class
Volunteer for 30 hours on approved projects—many are available throughout the year

To remain a Tree Steward in good standing, each year you must:
Complete 20 volunteer hours
Complete 8 hours of continuing education (opportunities provided by TSAA and others)
Pay $20 dues

About the Training Class

Training is divided into Four Modules:
Fall (beginning October 2) covers introductory material, Fall Tree ID, Soils, and Planting
Winter (beginning January 12) covers Winter Tree ID and Pruning
Early Spring (beginning March 19) covers Spring Tree ID, and Native vs Non-native Invasive Plants and Vines
Late Spring (beginning April 16) covers Right Tree/Right Place, Pests and Diseases, and Care of Mature Trees

Each module includes two to four mandatory classes. No more than two classes can be missed throughout the training, and any missed classes must be made up either by attending the class during the next round of training or finding a suitable replacement with the training coordinator.

Trainees must also attend one field session each module—in most cases, two sessions are scheduled for each topic, and trainees must attend one but could opt to attend both.

See the Training Syllabus 2018-2019 for details on dates, locations, and learning objectives.

What does the Training Class cost?

The $120 fee pays for all course materials and facility expenses. If you need a scholarship to attend, tell us what you will be able to pay and what your plans are for volunteer work. No one willing to volunteer is turned away for lack of funds.

How do I apply?

You can apply online by completing our Application Form

Once you are accepted, you will receive an email instructing you how to pay the fee via Paypal or by sending a check to our Treasurer.

I still have questions—how do I contact you?

Email us at We will get back with answers to your questions as soon as possible.

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A Bad Year for Forests Can Mean Hotter, Drier Climate

By Chelsea Harvey, E&E News

Tropical forests suffered some of their worst losses in history last year, according to a new report from the monitoring group Global Forest Watch.

About 39 million acres, or 61,000 square miles, of forest cover disappeared in 2017 — an area approximately the size of Bangladesh. That makes it the second-worst year on record, topped only by losses in 2016.

It’s discouraging news for global climate mitigation efforts. Healthy tropical forests store vast amounts of carbon, while deforestation can release that carbon back into the atmosphere.

And research suggests declines in tropical forest cover are taking their toll: Last year, a blockbuster study in Science concluded that tropical forests — because of their widespread destruction — are actually a net source of carbon to the atmosphere, rather than a carbon sink, as many experts had previously assumed.

The new data present “an alarming story of the situation for the world’s rainforests,” Andreas Dahl-Jørgensen, deputy director of Norway’s International Climate and Forest Initiative, said during a teleconference announcing the findings. “We simply won’t meet the climate targets that we agreed [to] in Paris without a drastic reduction in tropical deforestation and restoration of forests around the world.”

The findings were released Thursday, June 28, as representatives from around the world convened in Oslo, Norway, for an international forum on conserving tropical forests. A major focus of the conference includes the role of forests in global climate action.

Several recent estimates have underscored the significant contributions of deforestation to global carbon output — both the 2017 Science paper and a more recent estimate from the Global Carbon Projects may account for more than 10 percent of the world’s emissions.

But while the potential of forests to store or emit carbon remains their most substantial role in global climate efforts, some scientists note that forest losses may influence climate in other ways, as well. A new report from the World Resources Institute (WRI), also released this week to coincide with the Oslo forum, points out that deforestation can affect local temperatures and even alter the local water cycle. The report cites a range of recent studies on these effects.

Tree cover, for instance, has the potential to either warm or cool a local climate, depending on a combination of factors. On the one hand, trees tend to be darker in color than their surroundings, meaning they absorb more sunlight and more heat. On the other hand, they also release water into the air through their leaves, and they help to break up landscapes in ways that can disperse heat — both factors that may cool the local climate. Trees also release certain chemical compounds into the atmosphere that can have either cooling or warming effects.

But some recent research suggests that the cooling effect of trees may win out — meaning deforestation can drive local temperatures up and exacerbate the influence of ongoing climate change. A paper published in Nature Climate Change in April, for instance, links deforestation in the Northern Hemisphere to an increase in the intensity of hot days throughout the year.

Overall, the study suggests that deforestation probably accounted for more than half the warming that occurred over North America between 1920 and 1980. This effect has now been outstripped by the growing influence of human-caused climate change, but the researchers say deforestation may still account for nearly a third of the region’s warming (Climatewire, April 24).

A 2016 paper in Science had a similar message, suggesting forest losses around the world generally drive local temperatures higher. In fact, on a global average, it suggests the warming they produce may be the equivalent of about 18 percent of the influence from human-caused greenhouse gas emissions.

Other research suggests that deforestation could affect regional precipitation patterns. Trees lose water through their leaves, putting moisture back into the air — so tree cover losses can lead to drier local climates.

The effect may be particularly pronounced in tropical rainforests. One 2015 study found that deforestation in the Amazon basin reduces the region’s rainfall — and suggests that if the current deforestation rate continues, average rainfall throughout the Amazon basin could decline by more than 8 percent by 2050.

The point, the WRI report notes, is that “tropical forest loss is having a larger impact on the climate than has been commonly understood.”

Deforestation and degradation contribute substantially to global carbon emissions, thus helping fuel the progression of human-caused climate change. And at the same time, other non-carbon climate effects of deforestation may also be compounding the influence of global warming.

“When you add up these impacts of forest loss, one thing is clear: People living closest to deforested areas face a hotter, drier reality,” said Nancy Harris of WRI, who co-authored the report with Michael Wolosin of Forest Climate Analytics.

The new findings from the Global Forest Watch add renewed urgency to the global conversation on forest conservation and its role in international climate mitigation.

“A lot is hinging on our success in reversing these trendciences,” Dahl-Jørgensen said.

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Upcoming events of interest to Tree Stewards and tree lovers

Monday, July 9, 11 a.m.,  Mature Tree Campaign webinar, your computer

Learn all about Tree Stewards of Arlington and Alexandria’s new campaign to persuade homeowners to cherish and save their mature trees from destruction and disease. Details about how to join will be announced closer to the date. You can watch from home or join other tree lovers at viewing parties.

ATTEND IF YOU CAN: Tuesday, July 10, 7 – 8:30 p.m., Mature Tree Campaign in-person training, Fairlington Community Center, 3308 S. Stafford St., Arlington

How should Tree Stewards talk to property owners about their mature trees? What should we say? What should we not say? How can we direct them to an arborist? Jim McGlone, urban forest conservationist with the Virginia Department of Forestry, will answer those and many more questions to help us promote the mature tree campaign. Free.

Thursday, July 12, 7:30 – 9 p.m., Grasses: the good, the bad, and the just plain ugly! A Talk by Botanist Sarah Chamberlain, Arlington Central Library, 1015 N Quincy St. Arlington

Join botanist and grass enthusiast Sarah Chamberlain to learn about the different kinds of grasses found in the Mid- Atlantic Region. Good native grass choices for landscaping and beautification, landscape grasses that are not native to the area, and invasive grasses that pose a threat to our natural landscapes. Get to know the identifying characteristics of these species, find outwhich ones are best to plant in your native grass garden, and hear about some interesting research into invasive grasses and their control. Sarah Chamberlain is a botanist and curator of the PAC Herbarium at Penn State University and author of the new Field Guide to Grasses of the Mid-Atlantic Region. Free, sponsored by the Potowmack Chapter of the Virginia Native Plant Society.





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Digging This Spring

Press Photos (4)

Volunteers from INTUS Windows add soil around a White oak tree they planted in Alexandria’s Ben Brenman Park on April 5 with guidance from Tree Stewards of Arlington and Alexandria. From left are Jim McGorty, Karina Sicherle, Olena Prykhodko, and Connor McGorty. Photo by Sean O’Rourke for INTUS Windows.


Pre-schoolers from the Children’s International School in Rosslyn joined their parents and grandparents Sunday, April 29, in planting 32 trees in a previously weedy area along the southbound George Washington Memorial Parkway ramp to Key Bridge. Volunteers from Tree Stewards of Arlington and Alexandria, who already had planted 80 trees and shrubs in Alexandria in April, guided them, along with arborists from the National Park Service and Arlington County.

The planting, designed to enhance the atmosphere for commuters crossing Key Bridge between Rossyln and Georgetown, is the pre-school’s community service project and was joined by three other Children’s International Schools in Arlington to help the environment. Continue reading

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Barking Up the Trees

Bark tells a lot about a tree. It is key to identifying deciduous trees in winter, when most have lost their leaves and buds may be out of reach or sight. Naturalist Michael Wojtech advocates learning bark as a means of learning trees with the goal of becoming a native with the surrounding woods.

Mockernut hickory bark

Michael Wojtech notes the diamond pattern in bark of a mature Mockernut hickory (Carya tomentosa).

He wrote the book on bark, and last Saturday (March 10), he illustrated the dozens of variations in bark in both slides and a walk with about three dozen tree lovers at the National Arboretum in the District. Casey Trees, the D.C. tree-planting non-profit, invited volunteers and others from the area to experience Wojtech’s straighforward method.

Examine the bark at eye-level. Try not to look up for other clues, such as branching habit or remaining seeds or leaves. Consider where the tree is growing: wet, dry, uphill or lower. Think about the tree’s age: young, mature, old. And then match the patterns you see with about a dozen patterns typical of trees in our area and further northeast. Touch the bark. Is it smooth, tight, peeling, rough, furrowed, scaly, or pocked with lenticels?

Bark with furrows and ridges

Touching bark gives an added sense of its nature, in this case furrows and heavy ridges.

All are clues to the species of tree, though when a young or mature tree gets up in years, its bark can change radically. An exercise with photographs of 10 younger trees and photos of them later in life stumped all but three of the groups trying to match them up. As with most worthwhile endeavors, identifying trees by their bark takes lots of practice. So, go to your favorite trees. Get to know them. Give them a gentle pat. You’ll be rewarded with knowledge.

White ash branches and samaras

It’s hard not to look up, especially when the samaras of a White ash (Fraxinus americana) are hanging on.


Michael Wojtech’s book, which contains a handy key to identify bark and dozens of photos of bark at various ages, is Bark: A Field Guide to Trees of the Northeast. His website is





Posted in Bark, Education, Michael Wojtech, Tree ID, Winter tree ID | Tagged

Forestry Webinars to Watch

It may be sunny outside, but the light shines brightly from your home computer if you tune in to hear or participate in urban forestry webinars that are offered free. Most, if not all, are archived about a week after their live date, so you can watch and listen at your leisure and clock those Continuing Education hours on Track It Forward.

Logo of Southern Regional Extension Forestry's Webinar Series: Understanding Urban and Community Forests
The first of a year-long series by Southern Regional Extension Forestry starts at 1 p.m. today (Wednesday, March 14). The topic is Nature and Health in Communities: A Review of Best Available Science. Later this year, our own Nora Palmatier will participate in discussing Tree Stewards: Case Study of Two Virginia Urban Tree Volunteer Programs. For more about the webinar series, which is designed for extension agents and personnel but valuable for Tree Stewards too, click here.

If you ever wondered if size matters when selecting a tree to plant, check out this most recently archived of Can simple production or propagation decisions impact landscape performance of container-grown trees? What are the returns on your investment in the size of planting stock? Will the “little dogs” catch the “big ones” in the end? In this webinar, Dr. Michael Arnold of Texas A&M University will consider the big impacts of small planting stock selection decisions. Some of the findings might surprise you.

Tree Stewards are not confused about the term “urban forestry,” but just to clear up any misunderstandings, let popular Tree Stewards lecturer Dr. Jim McGlone explain in a webinar produced for Virginia Master Naturalists and available to all at noon Thursday, March 22. Details.



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It’s Invasive Species Week

Posted in Community Service, Events, Pests, Tree Care