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Porcupines and Hollow Tree Dens

Porcupines leave plenty of signs where they have eaten the inner bark, or cambium layer, of a tree. Bark is missing on the trunk of the tree, leaving fresh, yellow wood exposed, which often bears incisor marks.  An observation I have made over the years is that porcupines often de-bark around or near their hollow tree dens.  Typically, if a tree den is used year after year, they gnaw off bark each year, sometimes eating the old, scarred portion which, due to previous chewing, lacks cambium cells. This has led me to wonder whether fresh de-barking in the vicinity of their tree den entrance might have more, or as much, to do with a  porcupine’s staking out a claim on that tree than with its sustenance.  I have never come across any research that even mentions this phenomenon, and would welcome feedback from anyone who has.

2 responses

  1. Susan MacKenzie

    Question–on today’s walk, following a big snow and rain, the snow around hemlocks and firs looked yellow stained, but no prints. Is this some sort of tree resin or are there a lot more coyotes and deer marking territory with a powerfully long shot of urine?

    March 3, 2012 at 10:24 pm

  2. Hi Susan,
    I noticed the very same yellow stain at the base of hemlocks today! In fact, I considered using a photograph of it as today’s blog, but because I don’t know its origin, I decided to wait. It definitely comes from the tree, and I assumed it was the sap, but it was around the base of the trunk, not out beneath the branches, which might have broken…I can tell you it doesn’t have an odor, nor any taste, but I will have to try and find out exactly what it is!

    March 4, 2012 at 1:18 am

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