troubled tree

Discussion in 'Gymnosperms (incl. Conifers)' started by gobo, Jan 17, 2004.

  1. gobo

    gobo Active Member

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    with not much more than this snapshot to go on (taken in a rush) i wonder if someone might tell me 1) what kind of tree and 2) why it might be in (lethal?) trouble from the top down...
     

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  2. jimmyq

    jimmyq Well-Known Member 10 Years

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    I would say it looks like a Hemlock but its a bit out of focus to be real exact for my eyes anyways. it looks like the tree is having a serious emotional problem for some reason. Are there any other signs of problems besides the obvious dieback? at the base of the tree? any major changes to its environment recently (last couple of years), any spraying done near it for the control of weeds (the blackberries)?
     
  3. T. Shane Freeman

    T. Shane Freeman Active Member

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    I agree with 'jimmyq' in that your tree appears to be a hemlock (Tsuga heterophylla - perhaps?).

    It always difficult to diagnose via a picture, but there are some things that you can look for and add to this discussion to aid us in helping you.

    How long ago did this tree begin to dieback? A week, month, or year. If it died reletively recently, then the potential environmental problems could still be present. Do you live near an area that may have been recently sprayed............sometimes herbicidal sprays will drift through, only making contact with the upper portions of trees, therefore, causing a tree to dieback much like that of your tree. If there was a soil-borne toxin, history shows that the entire tree would show evidence.

    If this tree died back last winter or spring, did your area receive an unusual early/late frost. If a tree, shrub, or perennial hasn't properly acclimized by the time a early/late frost hits, they can succomb to cambial damage of juvenile branches or stems. Here in Manitoba, Silver Maples are often set back by such frosts. The tree isn't typically killed, just set back and deformed for several years.

    Another idea that came to mind when I looked at your attached photo was that your tree had developed a canker, which would have girdled the top and caused the visible dieback. Many of North American conifers/evergreens are subject to twig cankers and sometimes the occassional top killers. One such fungus that can infest hemlocks is called Phomopsis lokoyae' or Phomopsis occulata'. The real problem that arises when these cankers are discovered is that it is too late to remedy the problem!

    These are just a few ideas and things to think about.

    T. Shane Freeman
     
  4. Douglas Justice

    Douglas Justice Active Member UBC Botanical Garden Forums Administrator Forums Moderator VCBF Cherry Scout Maple Society 10 Years

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    This is Tsuga heterophylla (western hemlock). Note that it is associated with weedy plants, such as Rubus armeniacus ("Himalayan" blackberry). This suggests that it is a disturbed site, and as such, is not ideal for hemlock. My guess is that it was established before the disturbance, and what's killing it is related to moisture at the roots. For example, after a long, hot summer, hemlocks in the open tend to suffer. Or perhaps someone has piled soil over the roots, restricting oxygen diffusion into the root zone. Alternatively, its roots may have grown into a moist layer that later became saturated with the onset of the autumn rains. This latter scenario is a very common situation in the local urban environment.
     
  5. gobo

    gobo Active Member

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    good questions/answers.

    i haven't made it back to get more data, but can say that 1) pesticides are not an issue and 2) an area near the tree was waterlogged (my feet were wet taking the picture). the only significant disturbance would have been about 15 yrs ago, with the tree growing there subsequently.

    mr. justice might well have (once again) hit the mark with the water issue. i'm ready to say i believe his diagnosis, if it means i can still keep jimmyq's eloquent comment about emotional stress. but i'm still a bit confused about an established tree growing roots into a wet area and then drowning.

    why wouldn't roots NOT in the water zone continue to provide oxygen/etc.?

    another curiosity...why does a drowning tree die from the tip down?
     
  6. T. Shane Freeman

    T. Shane Freeman Active Member

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    If you were standing in water to take your picture, the ground was saturated. There was no more room for the available water to infiltrate. This condition isn't localized on a small scale. Chances are that the rootzone of this tree was totally saturated and therefore couldn't osmotically operate. Hemlock's roots systems are shallow and wide spreading......................therefore, if the soil was saturated there was no water-free roots available. Hemlocks do not have a taproot, like oaks for example, that would potentially enable them to absorb beneath this saturated area. As a result, you now have a tree illustrating the affects of excess water stress.
     

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