The Magnificent Elm Tree

The Perfect Tree for Albuquerque...

Many of the most magnificent trees in Albuquerque are of the species Ulmus pumila, known to most by its common name Siberian elm.  These are the large trees in many of our older parks and older residential areas, and in every empty lot, flower bed and street sign post around town.  These trees were introduced to our fair city by Mayor Clyde Tingley, on the assumption that they would do well here; a spot-on assumption, as it turned out.  The trees are the perfect tree for Albuquerque:

• very hardy
• very drought tolerant
• able to thrive in an desert, urban environment

In many ways, they are perfect for us.  They grow large, they are tough, they provide shade where most other trees would not.  They are easy to grow, having few serious pests or diseases.  So what’s the problem?

...With a Few Downsides

There are a few problems, it turns out.  One is that, as a wind pollinated species, they are prolific pollen producers, and anyone with allergies knows how miserable they can make us feel in spring when their pollen is carried on our spring winds to every nook and cranny of the city.  After the pollen has flown, there is a brief respite until the seeds fly – the so-called Tingley snow.  These seeds land everywhere and can germinate almost anywhere, and once the little trees have a year or two of growth under their belts, their root systems seem to be anchored all the way to Siberia.  Getting rid of them is a huge challenge, especially in the numbers they seem to pop up in.

Many of them also suffer from poor structure, leading to weakly attached branches and dangerous situations.  Those structural issues are made worse by our tendency to assume they are so hardy they don’t need irrigation.  That marginal water situation leads to dieback in the branch canopy, increasing the risk some of these older trees pose.

Any Possibility of Disease?

I mentioned the species has few serious pest or disease problems.  There are companies in town who will tell you the tree has Dutch elm disease and needs expensive fungicide injections to save it.  They are lying.  This species does not get Dutch elm disease.  They do contract a bacterial condition called slime flux, a.k.a. bacterial wetwood – almost every hardwood species is susceptible to this bacteria, and almost every tree in town has it.  The bacteria colonize old pruning wounds and similar sites where the wood is exposed, and then there is a smelly, wet ooze that comes out and drips down the bark.  The bad  news is that this condition is untreatable (especially with a fungicide – those don’t kill bacteria!).  The good news is, to quote my old colleague Dr. Natalie Goldberg (NMSU Cooperative Extension Service Plant Pathologist): the trees will die of old age before slime flux does any serious damage.  In fact, where the bacteria colonizes exposed wood, it creates pH and gas pressure conditions that wood decaying fungi can’t live in, so it’s almost a probiotic infection.

The trees sometimes get elm leaf beetle infestations.  These little critters can tear heck out of the foliage, but they won’t kill the tree.  They can be treated with insecticides, but often don’t need that.

Siberian Elm vs. Chinese Elm

By the way, many people call Siberian elm by the wrong name, Chinese elm.  This is a different species (Ulmus parvifolia), and there aren’t that many around town.  Expect to see more over the years, however – this elm is a small, attractive, hardy and well-behaved species, and it makes a good urban tree here in Albuquerque.  The other common name for this species is lacebark elm.

Love, Hate & Sustenance

So, we love them because they are tough and give us shade where little else will.  We hate them for their pollen and invasive seeds, and for how hard they are to get rid of when they’re growing where we don’t want them to.  We love to hate them because that’s human nature – we all like a formidable enemy to complain about.  And I have found that the full-size but still green seeds are quite edible, tasting like a nutty green leaf.  If my teenage kids are right about the coming zombie apocalypse, I know what survival food I’ll be eating for a week-and-a-half every spring.

Joran Viers
City Forester
Parks and Recreation Department
City of Albuquerque
505-857-8627

“Trees are poems that the earth writes upon the sky.”
― Khalil Gibran, "Sand and Foam"