Prothonotary Warbler

Prothonotary Warbler

Tuesday, 3 February 2015

Are trees lonely?

If trees could experience loneliness, the one species I would think is the loneliest is the American Elm (Ulmus americana).

They are most often seen by themselves along a road allowance, or a fence line. Here is one of the largest in the area, shown on a cold winter day. Measuring it at ~4.5 feet above ground, the standard height for what is known as diameter at breast height (dbh), it measures 1.25 metres diameter.

American Elm in winter
 It is located on a quiet gravel road (Harwich Line) just southeast of Blenheim.
American Elm in May

American Elm in November
 It is an attractive, and easily identified species. From a distance, a mature open-grown elm tree has a distinctive umbrella shape to the crown.

American Elms used to be very common on the eastern North American landscape...up until the first half of last century. All tree species will host an array of insect types that feed on leaves or burrow under the bark. A native bark beetle was a regular 'pest' of elm trees, but not a serious one. However early in the 1900s, a non-native fungus arrived from Asia, quite accidentally I suppose, but still a result of the settlement of non-native humans, and the results have been devastating. The native bark beetle burrows holes into the growing tissue of the host elm, and if the beetle came from an elm that was already infected, would transfer the fungus to the new host tree. As a result, mature elms across their normal range died by the thousands.

Elms are prolific seed producers and to their benefit, begin producing seed at a fairly young age. So there are lots of young elms that get a start on life, and if they are relatively isolated, may grow to maturity. But many just get started and die back, so they look quite scrubby along the road side.

Even some mature trees may have a scrubby base, such as this one along another quiet rural road between Blenheim and Ridgetown.

A much rarer tree in Ontario is the American Chestnut (Castanea dentata). It was a forest dwelling species, and the handful of individuals that remain are mostly still in forests. They were a dominant forest species up until about 1900. It too was the victim of an Asian bark fungus that arrived on the intentionally introduced Asian Chestnut. Having no resistance to this fungus like its Asian counterpart, the American Chestnut dwindled from comprising almost 30% of the forest trees to being almost completely obliterated.

American Chestnut
 This American Chestnut leaf was photographed in a crown forest near Simcoe.
American Chestnut flowers
 These American Chestnut flowers were ones I photographed on a tree just west of Thamesville, in the early 1980s. The tree no longer exists.
American Chestnut fruit
The photo of the fruit cluster was taken in a forest southeast of Ridgetown in 2013.

While the American Chestnut is usually surrounded by other tree species, it could be considered a lonely species since there is seldom more than one or two of its kind in any location.

American Elm, does still occur in the forests, but some of the most impressive individuals are well away from a forest. Being relatively isolated may work to their benefit: they are a greater distance from other individuals which may be affected by the fungus, so their chances of the fungus being transferred causing a premature death is reduced. Hopefully this individual along Hwy 21 a bit south of Thamesville will have a long and productive life!





2 comments:

  1. Allen: Your Blog tonight is of special interest to me--a joy to read and reminisce !
    I have watched over that Elm tree on Harwich Rd. for many long years, wondering
    about the fateful day when it might meet up with "an axe", by someone wanting
    just a little more planting space. I did speak with someone from Ridgetown
    College, sharing it's location. I had hoped it would get a plaque, or some means
    of protection at the very least. Nothing yet, that I am aware of anyway.
    The Chestnut trees of long ago. Memories again ! As a child from a very large
    family---it was a yearly tradition that we packed up a lunch bag, and headed out
    to that very same area you mentioned. We spent the long day harvesting
    chestnuts for the coming winter [ I suppose ]. I remember my mother roasting
    the chestnuts in the kitchen wood stove. Mmmmm! My brothers, also, went
    door-to-door peddling the nuts. My first encounter--with a little green snake--
    was on one of those "nutting days ". Yikes ! It was in the tree where I was
    picking. Thanks for the memories !

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    Replies
    1. Hi Irene. Thanks for your comments. I am so glad you enjoyed it and that it triggered some great memories for you. I also keep an eye on the Harwich Line tree, obviously. The combination of ag equipment cutting off roots, or having some nasty chemicals spilled at the wrong time, would be devastating, as would a landowner who just wants another row or two of crop, even though it is on municipal property. Perhaps this tree, or ones like it, could be recommended as a C-K Heritage Tree given their relative scattered and low numbers and the ongoing threats they face. Technically they aren't rare....yet, but there may be other justifications for their heritage status.

      Thanks again.

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