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Bill Pramuk

Bill Pramuk

I have just returned from the American Society of Consulting Arborists (ASCA) annual conference. Moving around the country for interest and variety, this year it was in San Diego at the Paradise Point conference center, with an afternoon outdoor series of field presentations at Balboa Park.

For me, the great appeal of arboriculture is its wide range of knowledge, applied science and its dynamic nature. We are dealing with changing, living things: trees, environment and people and ever-changing knowledge. It is daunting to meet and hear presentations from professionals whose knowledge is deep, wide, and up to date. As the saying goes: “The more I learn, the more I realize how much I don’t know”.

Talks covered: caring for mature trees, soils, a live in-person look at tree pests under a microscope, irrigation management, wildlife protection laws for arborists, plants and pests in a warming world, unintended consequences of pest control, risk assessment, the art of communication, expert witness, a “mock deposition” by a consulting arborist, and more.

Here are a couple of examples I found engaging:

— Conservation Arboriculture: Caring for Mature Trees

Having seen many older trees removed that might have been saved if there had been enough advocacy and political will, I particularly enjoyed this presentation by certified consulting arborist Philip Van Wassenaer, founder of Urban Forest Innovations in Toronto, Canada.

Philip presented his views on mature, older, or ancient trees as “Veteran Trees,” deserving the care and attention devoted to other heritage artifacts. There are practical strategies for maintaining such trees for the benefit of current and future generations.

Recognizing that large old trees have been through a lot in their lifetime, with accumulated wounds and decay, they may still provide benefits for us and for wildlife. He suggested we think of their condition as having “features” rather than “defects.” I saw this as a nice twist in thinking to help us appreciate older and historically significant trees.

A great example of people who think this way is the Ancient Tree Forum, an organization in the UK dedicated to preventing avoidable loss of ancient or veteran trees. A visit to their website shows how much they have accomplished since their founding in 1993. Trees are listed by regions throughout England, Scotland and Northern Ireland, along with a list of Heritage and named trees.

Referring to the work of Pierre Raimbault in 1995, Van Wassenaer emphasized the life stages of trees from the young maturing stages to early and late maturity, early, mid and late-ancient phases, he said: “Older trees must get smaller.”

It is natural for ancient trees to “retrench”. They can live on, contributing significant habitat for wildlife of many kinds and providing a sense of history and beauty for us. We as arborists and tree managers can anticipate and emulate this through a process of reduction pruning and other methods; options too often overlooked when an older tree is perceived simply as a hazard.

On the subject of “What a Warming World Means for Plants and Their natural enemies”, Entomologist Dr. Michael Raupp of the University of Maryland, saying that the “warming trend is clear” provided facts confirming it and its direct effects on wildlife. Here are two:

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— Cloud forests in Costa Rica are being pushed to higher elevations because of it. The mountains are only so high. When the clouds rise higher, the cloud forest animals and plants go extinct.

— Mountain pine beetles formerly confined west of the Rocky Mountains by cold winter mountain temperatures are now crossing the mountains and attacking forests to the east.

He cited numerous negative effects of the warming trend on the delicate balances between insects, plants and temperature. Global warming, or global chaos as another speaker phrased it, is real and has more implications than many folks want to know about.

There is so much more to tell. Perhaps another time soon.

Learning is good.

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Bill Pramuk is a registered consulting arborist. Visit his website Email questions to or call him at 707-226-2884.