Ash tree news: linking tree health to human health?

Ash trees are under threat in many areas around North America thanks to the emerald ash borer. A march of that insect threat continues in New York State as well, according to this account from David Fugura at

With the confirmation of EAB in Delaware and Otsego counties, New York now has 15 counties where EAB has been found. Most of the infested areas are small and localized, while more than 98 percent of New York’s forests and communities are not yet infested.

NCPR has covered this topic for years, and the outlook for ash trees has not been terribly hopeful. Here’s a Sept. 2012 map of affected and quarantined counties in NYS:

(image from the NEw York Invasive Species Clearinghouse, Cornell cooperative extension invasive species program)

(image from the New York Invasive Species Clearinghouse, Cornell cooperative extension invasive species program)

Apparently, the common ash in parts of Europe and England is also struggling with Chalara fraxinea fungus, which causes dieback. That disease threat has spread to Wales (which is easy enough on a contiguous land mass). Sadly, that has also hopped the surrounding sea and is now reported in Ireland.

Ash trees are a classic element of landscape and culture in England and Wales. (Indeed, even in far-off Hawaii I was taught the Welsh folk tune “The Ash Grove” back in elementary school.) The UK’s Gaurdian called the situation there “a disaster in the making“.

Matters do look grim for the poor ash tree.

Recent news reports add a wrinkle to that dour outlook: there may be some relationship between higher rates of human mortality and threats to tree health, according to a study published in February by the American Journal of Preventative Medicine: The Relationship Between Trees and Human Health: Evidence from the Spread of the Emerald Ash Borer

As summarized by an article in the Washington Post:

A study in February’s American Journal of Preventive Medicine showed that deaths from cardiovascular and lower respiratory illnesses rose as ash trees vanished. The study found that the EAB’s effects can be linked to more than 21,000 deaths — an additional 24 deaths per 100,000 people every year, a 10 percent increase in mortality for those diseases.

Is there a causal link? Well, that awaits further study. It is generally understood, though, that healthy trees do contribute to a healtier environment for living things, including humans.

Ash makes up a significant percentage of trees in the Ottawa area, perhaps as much as 25%. Most or all are expected to be lost over time to the current insect threat. The Ottawa Citizen’s Tom Spears wrote about this recently, in light of the study in question:

The greatest jump in deaths was in communities where people had higher-than-average incomes and more education, which are often the places with the most trees.

One Ottawa physician says this is more evidence for protecting the ash trees.

“You want them because they are beautiful, natural cleaners (of air) and protectors of us,” said Dr. Curtis Lavoie of the Children’s Hospital of Eastern Ontario.

“I see a lot of asthma, a lot of emphysema, a lot of pneumonia” as an emergency physician, he said. “It’s on the rise, and I think it’s largely related to pollution.”

It may be that healthy trees in general – any trees – will provide a protective benefit. Which raises some questions. Should planners make a special effort to replace lost ash trees with an equivalent number of other tree species? Or is this a bigger lesson? Perhaps all trees, all species, need conditions that will keep them in continued health.

If so, that’s going to be a tall order.

I am put in mind of the old saying: “The best time to plant a tree is 20 years ago. The next best time is now.”

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8 Comments on “Ash tree news: linking tree health to human health?”

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  1. Michael Greer says:

    Here in St Lawrence County we have a bit of an Ash die-off going on too. I’m not sure which of the several culprits to blame, but my logger friend has worked in some woodlots that are losing their ash trees at a break-neck pace. This is quite worrisome as some parts of the county are nearly all second-growth Ash (like Rt. 56 near Massena) with hardly any other species to take up the slack. Complete deforestation of much of the St Lawrence valley is a distinct possibility.
    What are our local foresters seeing?

  2. Paul says:

    “complete deforestation”? Is it all Ash trees in SL county?

  3. Paul says:

    Sorry not just the county you say but the entire valley?

  4. Michael Greer says:

    I tend to look out the window (probably more than is safe) when I drive. I pick out the dead tops, and have gotten pretty good at identifying species. Indeed, along the roads in Madrid, Lisbon and up toward Massena there are an alarming number of dead trees. We expect to see dead or dying elm trees, but youngish Ash trees shouldn’t be dying at the rate that I’m seeing.
    In those areas where Ash seems to make up 90 or 95% of the regrowth forest, a significant loss of Ash would look a lot like deforestation. In a mixed stand, (like in the foothills), the loss would not be as obvious as ash might only make up 5 to 10% of a stand of trees
    And no, I’m only familiar with the St Lawrence County part of the river.

  5. Michael Greer says:

    So let’s hear from the forestry community. While we have not seen the Emerald Ash Borer here yet, something is killing off these trees. I have heard mention of something called “Ash Yellows”, and I don’t know anything about the above mentioned fungus, so what is it?

  6. knuckleheadedliberal says:

    Time for a list. Tree species that seem to be severely affected by some sort of blight, infestation, or just seem to be dying off for some reason or another:
    Chestnut, Elm, beech, maple, ash. I’m told there is some sort of thing affecting white pines, though I haven’t really noticed it. Some stands of hemlock I see seem to be pretty sick.
    Any others? What trees are still healthy?

  7. Michael Greer says:

    I read a study years ago, about the relationship between dirty air and tree foliage. Their contention was that the North American tree with the most leaf area was the Chestnut, followed by the Elm, and on down the list of ailing and troubled species. The trees that worked hardest…cleaning the air and cranking out oxygen, were the first to be overcome by pollution, and that the rest would follow if we didn’t get a handle on air pollution.
    The skies over this country are a lot cleaner than they were when I was a kid in the sixties. The clean water act, and the clean air act have done much to save the environment, and lives…until we stopped enforcing them…..Something about getting government off our backs….

  8. Jim says:

    Ten years ago a logger friend told me that the EAB had arrived in the Hammond area. He showed me a piece of ash, riddled with holes/tunnels, that he had cut the previous week. In the last three years I have cut 25-30 good sized (24″-30″) dead ash here on the farm. Although they didn’t show signs that the borer was responsible, there appears to be a significant die-off occurring. I have also noticed a marked increase in a weird growth on the hickory trees that has been around for years, but has now begun to kill what were healthy specimens within a couple of years of attacking them.

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