Yesterday I gave a presentation at an Urban Forestry symposium here in Seattle. One of the sidebar conversations I had came from a urban forester who had (to my mind, anyway) a different way of looking at urban street trees. I’ve bemoaned for years that our trees die far too young – we plant species that should live for decades or even centuries, only to watch them fail and die in a fraction of that time. Urban conditions take their toll: compacted, poor soils, reduced sunlight, increased temperatures, etc. It’s not surprising that our trees just don’t hang on as long as they should.
But…what would happen if we took the “planned obsolescence” route? In other words, rather than planting species that have long life spans and somehow expecting them to overcome all that the urban environment flings at them, how about choosing trees with shorter life spans? Sure, there will still be replacement costs, but they will be expected and planned for.
So – should we continue to fight against ridiculous ordinances, unrealistic planting plans and unworkable tree selection lists? Or should we lower our expectations of our urban forests?
(And now I’ve gone completely off track mentally, remembering the “Lowered Expectations” skits on MadTV. Feel free to watch one!)
Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist. She is WSU’s Extension Urban Horticulturist and a Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets.
Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019).
In 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. She also is one of the Garden Professors – a group of academic colleagues who educate and entertain through their blog and Facebook pages. Linda’s contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award.
"The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors
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14 thoughts on “Maybe an early demise is better?”
i completely agree! i’ve often wondered why they plant trees under power lines just to go back later & demolish the tree!
Well, I think that we should expand the trees that we used on the streetscape. Whether it is planned obsolescence or size, I have seen too many instances of simply the wrong trees planted in public places. Trees that are too big or too small for their location; trees that are not adapted to their location; or trees that are butchered because of a lack of maintenance.
The wrong tree in the wrong place is definitely an ongoing problem. And I appreciate the practical approach of planned obsolescence.
Still, I can’t help but feel a little bit like planning for urban tree obsolescence is like giving up – and giving developers and others an excuse not to change the way they plan for urban trees. There are real solutions for improving the lot (har har) of urban trees. We can do better for them. I worry about giving people an excuse not to try.
Then again, my worries are not going to change anyone else’s behavior!
I agree, Leda–more often than not, it’s the place that’s wrong, and there’s plenty we can do to improve those planting conditions. Providing more generous soil conditions has the added benefit of increasing the diversity of tree species that will be successful in urban conditions–which in turn minimizes the impacts of disease on urban forests. Planned obsolescence might be an appropriate strategy for particular sites, but one concern that comes to mind is that municipalities would have less flexibility when it comes time to remove a tree. There’s less urgency to remove an otherwise healthy beech, for example, because it is outgrowing it’s place, than a mountain ash that
is past its prime and falling apart in the public right of way. With budgets stretched so thin these days, postponing tree pruning or removal for a year or two can be significant.
I agree, Leda–more often than not, it’s the place that’s wrong, and there’s plenty we can do to improve those planting conditions. Providing more generous soil conditions has the added benefit of increasing the diversity of tree species that will be successful in urban conditions–which in turn minimizes the impacts of disease on urban forests. Planned obsolescence might be an appropriate strategy for particular sites, but one concern that comes to mind is that municipalities would have less flexibility when it comes time to remove a tree. There’s less urgency to remove an otherwise healthy beech, for example, because it is outgrowing it’s place, than a mountain ash that is past its prime and falling apart in the public right of way. With budgets stretched so thin these days, postponing tree pruning or removal for a year or two can be significant.
I’m actually a fan of the planned obsolescence route. Cities and neighborhoods change. There are budgets and priorities that don’t always include sensible urban forestry. It makes sense to me to plant something like “weed” trees knowing they grow fast and easy and that they can be replaced when there is money in the budget for the right trees to be planted with a practical maintenance program.
I don’t like the term ‘planned obsolescence’; it leaves the impression that trees are essentially disposable. But I have come around to a similar view that we need to have realistic expectations about the useful life-span of street trees. This view recognizes not only biological limitations of trees in stressful environments but also limited resources of urban and community forestry programs to provide effective remedial treatments – either pre-plant or post-plant. It’s easy to say, “Well, if we alleviate compaction…” or “If we add this or add that…” but the reality is we’re tinkering at the margins. I think a really useful study would be to survey urban foresters and compile data from the urban forestry literature and come up with a set of realistic or functional life expectancies for street trees around the country. This could provide some decision support when trying to decide on remedial measures for trees near the end of their functional life versus taking them down and starting over. Whataya think, Linda? Maybe we can work up something for the next NUCFAC cycle…
Bert, I like your idea. Let’s try to do a NUCFAC application. Are you coming to WA at all this summer?
Your idea of planned obsolescence is an excellent one, and here’s why:
I have often wondered why weedy fast-growing trees aren’t planted in city conditions. A poplar or cottonwood will be providing shade at age 5, when an elm will be a stick and an oak a sprout. Yes, poplars are weedy, but a tree planted in a hole in the sidewalk is not very likely to colonize the surrounding cement. Yes, poplars don’t live very long under the best conditions, but their USEFUL lifespan is pretty good, since they start fast and young.
Plus, who are we kidding, anyhow? Urban trees get into all kinds of scrapes (car accidents, for one) which cause terrible problems–oak wilt entering through a car wound, for example. Or Emerald Ash borers coming into trees designed to last for far longer than they are going to actually last. (About half my city’s street trees are ash–what a horrible mess THAT is going to be any day now….)
In other words, the “lifespan” or “usefulness” or “weediness” of a tree as measured growing in an idyllic meadow somewhere isn’t a very useful measure of its its potential for surviving and casting shade in urban situation. Fast growing weedy trees should be used more often, and a “planned obsolescent” approach would make this possible.
@TK, unfortunately it’s not as simple as planting poplars or willows. Not only do they use a lot of water, but they are prone to breakage. Poplar in particular is such a potential hazard that its use is restricted in some cities. So we have to figure out something that’s fast growing, yet not hazardous to people and property.
TK, I agree with Linda that poplar and willow are poor choices for the reasons noted. However, focusing on function and a realistic expectation of functional lifespan could cause us to re-evaluate other spp.
FOr those who don’t know about it Cornell has an Urban Horticulture Institute:
And came up with “Structural Soil”
I don’t know your idea is right or wrong. Because I don’t what kind of climate is there. But trees are damage. How can recover them?
It is a though question and great dilemma if you ask me because there is sense in both sides, but do we really think that spans that live shorter will not live even less when planted in the city, may be we should find a spices that are really adaptive and they can be grown in any conditions.