The Ethical Branch

In the PNW, we bear witness to best management practices (BMP's), and seemingly the worst as well. I feel a tide has changed much with the climate in our industry. It appears more PNW Arborists are well-aligned with our code of ethics and BMP’s, and some may have continued to use “loopholes” to cut corners, or an assimilated professionalism to sustain a career. Whether or not you are one or the other, we must continue to learn and engage each other with “proper practices". It makes our industry stronger and respected among the world community. This may translate into greater opportunities, if desired, or more jobs/fields in which we may guide our success for the planet, or profit, or both. Read More "The Ethical Branch"

American Hornbeam Cultivars – Carpinus caroliniana: Native Flame®, Palisade®, Ball O’ Fire™, & Rising Fire®

In a Tree Profile over 10 years ago, I raved about the American hornbeam, Carpinas caroliniana and still feel the same today. With the more recent arrival of several new cultivars which display some of the best characteristics of this species, an update on this tree is in order.

Let’s start with its generic attributes. The pioneer nicknames of “Blue Beech”, “Muscle Tree” or “Ironwood” of the species are suggestive of what a tough Midwest native tree this is. Considered a small tree, the ultimate mature size is approximately 30-feet tall by 20-feet wide. They may grow larger under optimum conditions. It has few, if any, disease or insect pest concerns in this region and as the name implies, has branches “of steel”. In my experience, branches can bend like rubber and not break, which is a good testament for strength. This is a good urban tree characteristic.
Read More "American Hornbeam Cultivars – Carpinus caroliniana: Native Flame®, Palisade®, Ball O’ Fire™, & Rising Fire®"

Women In Arboriculture

There are so many reasons to be an ISA Certified Arborist in 2019. We are the ones that can mitigate development consequences and edge effects. We can retain trees, create beneficial wildlife snags rather than remove all the material, preserve old trees through pruning and cabling, design storm water runoff away from valuable trees through rain gardens, replant when removing trees, and plant natives and non-native species.  Wait, what – non-native? Yes! Know when a site has changed to a new condition and recommend the right plant in the right place. The urban forest is not like the native contiguous forest. People live in cities, and cities need trees. Urban foresters and ISA Certified Arborists are important for adaptable urban forests. (“A city without trees is dead. Alex Shigo”)

Do you ever ask yourself what it means to be a female arborist? Or perhaps, what your friend or wife goes through to practice Arboriculture? Historically, the Forestry and Arboriculture fields have been male dominated, and I feel that it is still male dominated. I climb like a girl because that’s what I am; those words in that order have generally been derogatory. But I am a girl. When I walk into a board room to lead a meeting, am the only female in the room, and I know the most about the trees and the stakeholders, do I have to consider my gender? When I’m on a consult or in charge of my job site with male homeowners and other male arborists, do I consider it? Because I run our male tree crew and our family with my husband, do I have to consider it? Well, the answer is yes and no.

Read More "Women In Arboriculture"

To PPE or Not to PPE

Although hardhats and hearing protection are, for the most part, in use by tree workers across the PNW, insidious attitudes are always lurking towards PPE whether it is aimed at premium protective equipment, PPE options not required by regulators (gloves, protective footwear or chainsaw pants in some parts of the chapter), PPE care, or the ongoing inspection and replacement of PPE. I expect that most tree care operations and their employees consider themselves to be compliant on the PPE front (particularly those that read this newsletter). If you feel that to be the case with your workplace, I have one question to ask:

Does your workplace request third-party observations and recommendations (formal or informal) on interventions that might improve the outcomes of worker health and safety, worker ergonomics and worker efficiency via PPE?

Hopefully the answer is yes.

It’s probably time to start talking about PPE as a program or system rather than a thick piece of plastic intended to keep skin from disappearing or bones from shattering. Read More "To PPE or Not to PPE"

Upcoming Tree Climbing Workshops

PNW-ISA is offering two unique climbing workshops in Seattle, Washington in June. Registration is now open for the Women’s Tree Climbing Workshop and the Advanced Tree Climbing Workshop.

Women's Tree Climbing Workshop

June 7-9, Seattle, WAJoin the Waitlist

PNW-ISA presents Women's Tree Climbing Workshop. June 7-9, 2019, in Seattle, Washington. Enroll at

PNW-ISA has teamed up with the Women's Tree Climbing Workshop to offer a fun and safe space to learn to climb. Taught by International Tree Climbing Championship competitors Bear LeVangie and Melissa Levangie, this workshop is for women who have never climbed trees as well as those who have prior experience and want to improve their ability.

PNW-ISA thanks our generous 2019 sponsors who are helping to make the Women’s Tree Climbing Workshop possible:

Bartlett Tree Experts
BC Plant Health Care
Champion Tree Care
Christina Pfeiffer
D. Clark Arboriculture
Davey Tree Expert Company - Canada
Davey Tree Expert Company - USA
Fruitful Tree Care LLC
Morgan Holen and Associates
Out on a Limb Tree Co
Pfanner Canada
Radix Tree & Landscape Consulting
Renaissance Tree Care
Seattle Tree Care
Shelter Tree Inc.
Sonshine Tree Care
Sue Nicol
Sweaty Betty Tree Care
The Tree Service
Tree Solutions, Inc.
The Tree Stewards


We are looking for additional sponsors. Interested in sponsoring this year's PNW-ISA Women’s Tree Climbing Workshop? Your sponsorship will keep workshop registration fees affordable by helping to cover instructor travel costs, lodgings, food, climbing gear, and scholarships for participants in need. Please contact if you are able to support this event.

Advanced Tree Climbing Workshop

June 10, Seattle, WA - Register Now

PNW-ISA presents Advanced Tree Climbing Workshop. June 10, 2019, at the Talaris Conference Center in Seattle, Washington. Enroll at

While on the west coast, the LeVangie sisters will also lead an Advanced Tree Climbing Workshop for climbers who are beyond the basics. This workshop is open to all genders. Come learn advanced climbing techniques from an experienced team.

Full schedule and course descriptions for PNW-ISA workshops available at

A Community of Trees

Many cultures regard trees as part of their heritage. How is inherited knowledge passed from generation to generation through trees? How can we use trees to tell stories and connect with our ancestors? In this article, we’ll explore how cultures have shaped our “human-tree” relationship in different parts of the world I have traveled.

Tu Di Gong, Gods and Trees

During the summer of 2010 I packed my prized climbing set-up, a couple changes of clothing and headed to Hong Kong, China. There I joined my colleague, Will Koomjian, to complete contract work for the Hong Kong Government. Upon arrival at the airport, I unfolded the directions I had jotted down on scratch paper. The notes depicted a bus transfer and an hour and a half trip through the Northern Territory of Hong Kong. My destination, Sui Hang San Tsuen, bordered Shenzhen, China. I was greeted by Don the local arborist and promptly put to work at a nearby site. Jetlagged, on the first day, I was shown how to use GPR and Tomography to examine the underground roots of old, roadside Melaleuca trees before an improvement project. I was impressed.

Over the next year, Will and I found ourselves climbing and writing reports for hundreds of spectacular specimen trees managed by the Hong Kong Government. Many of these trees were deemed Old Valuable Trees (OVT’s) which gave them special recognition and protections. This program could easily be compared to a heritage tree program ran by a city, county or state here in North America.
Read More "A Community of Trees"

Some Thoughts on Tree Risk

Early in January, two strong winter storms passed through Snoqualmie, where I work full-time. The second of these storms lasted about 20 hours, and at its peak, winds were 40-45 mph sustained with gusts in the mid 50’s. Beyond cleaning up tree failures and doing follow-up risk assessments, I spent a lot of time talking with scared residents. Many were concerned about the risk that trees pose to their families, and were convinced that swaying trunks were an indication that trees were about to fail.

In storms like these, there is a perceived high risk of trees. The actual risk for people (outside of our industry) is quite low, even during storms. As a juxtaposition to this, the perceived risk of driving a car or being on roads is low, whereas the actual risk is quite high.

Let me backup these assertions. A study by Thomas Schmidlin: “Human fatalities from wind-related tree failures in the United States, 1995–2007” discovered in that period, 407 deaths were caused by trees. By comparison, in the same time period, 416,268 fatalities were recorded on US roads by the National Highway Traffic Safety Administration. In other words, it seems that the average person is 1000 times more likely to die in a traffic accident than by a tree falling on them. However, I don’t think many of us think when we get behind the wheel: “Wow, I’m about to do a really risky thing”.

This is leading me to an ethics-check, and some questions I ask myself, that I’ll ask you too:

1) Do you communicate the benefits of trees, as much as the risks, to clients?

2) Do you have any way to put the risk of trees in perspective for the average person?

3) Are you focused solely on the trees when you risk-assess, or do other considerations creep in and affect your judgement?  Examples: The risk-tolerance of the client, the possibility that you may get paid to remove the tree, your own fear about being wrong in assigning a risk rating.

Culturally, we have accepted the risks that come from driving.  I think it’s part of our job as Arborists to help people understand the risk of trees, in balance with the benefits, and make sure there is a similar cultural acceptance of trees.

Root Removal Best Practices

To keep up with research based changes in arboriculture and urban forestry we rely on guidance from a number of professional sources. The most important are the American National Standards Institute (ANSI) Practices and Limitations.  Because the ANSI A300 standards are written in a very austere style, they are interpreted and expanded upon in the ISA Best Management Practices (BMP’s). Both of these types of publications guide professionals in writing and implementing tree work.

Read More "Root Removal Best Practices"

Treasure Valley Tree Selection Guide: A Process of Transformation

The Cities of Boise, Caldwell, Eagle, Kuna, Meridian and Nampa, Idaho are proud of their trees! It was with this sentiment of value and appreciation for our trees that the TV Tree Selection Guide was created. Based largely on the original version from the Boise Parks & Recreation Department’s Tree Selection Guide developed by the Urban Forestry Unit in 1995, the new guide was fashioned.

It was time…time to broaden tree species selections to include new cultivars. And, remove old ones that were not performing well. This was a labor of satisfaction for everyone involved. Read More "Treasure Valley Tree Selection Guide: A Process of Transformation"

Photos from October Tree Risk Assessment Workshop

The PNW class “Common Fungi Affecting PNW Trees and Implications for Tree Risk Assessment” was a classroom/outdoor course in tree diseases, and particularly anyone conducting risk assessment of trees with disease.  Led by Dr Julian Dunster and Professor Bob Edmonds.

The diseases covered included Phaeolus schweinitzii, Heterobasidion occidentale, Armillaria ostoyae, Porodaedalea pini, Kretzschmeria deusta, Phellinus sulphurascens, Neofusicoccum arbuti and others.

Morning lectures covered visual assessment techniques for disease, using a combination of signs and symptoms of common diseases in native PNW trees. Sonic tomography and resistance drilling will be discussed as examples of advanced risk assessment techniques.

The afternoon was spent outdoors examining diseases of Douglas-fir, western hemlock, western red cedar, bigleaf maple, and Pacific madrone. The types of wood decay, fungus fruiting bodies, as well as structural and risk implications will be covered.

The PNW is grateful to have Roger Barnett attend, to learn and capture moments on digital film for all to take a peek into this course.  Please see some of these moments on this flicker account below: