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Tree rings

  1. May 3, 2010 #1
    Sorry if this is the wrong section (already posted it in the biology forum and got no response) but this question comes from a convo I had with some friends the other night..

    Say you were able to grow a full size tree indoors (assuming you had the space, nessesary lighting, soil, etc..) and kept it under 18 hours of light and 6 hours of dark indefinitly. Would it still create tree rings? Would it loose its leaves? What is the mechanisms for these?

    thanks for any insight provided..
     
  2. jcsd
  3. May 3, 2010 #2
    Obviously that's a hypothetical question, since only somebody who did try that can answer it.

    Tree rings however reflect the annual seasonal cycle of that tree, which may include seasonal variation of -for instance- light, temperatures, moisture and wind. If you don't simulate those indoors, it's likely that the growth and ring forming is affected.
     
  4. May 3, 2010 #3

    jim mcnamara

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    Staff: Mentor

    Tropical hardwoods in the cloud forest have rings. That is a very stable environment, over time. Rings are the result of laying down different cell types in the xylem tissue usually under different environmental conditions.

    Back in the 50's this kind of experiment was tried in a greenhouse at the University of Maryland. I don't know the outcome ring-wise, but the subject trees went into a slow, steady growth state. Overall growth rates (as measured by xylem production- delta girth) were significantly less than controls kept outside in changing seasons.

    I cannot find a reference... I do know the control trees used to be out near Testudo the terrapin. Used to be circa 1960. I wonder if Testudo is still around....

    Also note - under short term stress trees may produce what appears to be more than one "annual" growth ring per year. Insect mediated defoliation as an example.
     
  5. May 5, 2010 #4
    it seems conceivable that there would be no rings, what would cause them?
     
  6. May 26, 2010 #5
    thanks for the answers!!
     
  7. Aug 19, 2010 #6
    Sorry if I came in late. You have had some helpful answers, but here are two remarks:

    1: Trees without rings would most likely be palms and the like, that do not have the same wood structure.

    2: Not all trees that have rings have proper (annual) year rings. One has to be really careful when one does not know the biology of the tree species in question. This is a common development in trees that grow in more or less seasonless regions or in hard environments where they can't necessarily afford to grow in hard years.

    Cheers,

    Jon
     
    Last edited: Aug 19, 2010
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