Friday puzzle: wet trunk

Another diagnostic question today.  Below you can see the lower portion of a tree trunk whose left half is obviously wet:

What is directly causing the wetness (in other words, what environmental factor), and can you guess what led to this problem indirectly?

I’ll eliminate some of the obvious possibilities:  it’s not from dog pee, nor is it from a directional sprinkler.  And the answer to the second question is not in this close up photo, but will be revealed on Monday.

Why do I torment you like this?  Well, if nothing else, it gives you an idea of what distance diagnosis can be like – which is what we tend to do more and more, thanks to the internet and digital cameras.  Someone will send a photo of a plant problem and expect us to figure it out, but the answer may lie outside the field of view.

In any case, have fun!

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Linda Chalker-Scott

Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist. She is WSU’s Extension Urban Horticulturist and an Associate Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019). In 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. She also is one of the Garden Professors – a group of academic colleagues who educate and entertain through their blog and Facebook pages. Linda’s contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award. "The Garden Professors" Facebook page - "The Garden Professors" Facebook group - Books:

10 thoughts on “Friday puzzle: wet trunk”

  1. almost 2pm est and still no guesses well i will give it a go
    There is something attached or very near to the tree which traps rain and then water leaks/drips very slowly down the trunk. Something tells me this photo is part of the
    “the things people do to trees” collection.

  2. Did you come to my yard? My lovely Siberian Elms display this. The only tree worse than a box elder is a siberian elm IMO. I believe its called slime flux due to some pressure build-up under the bark. I think it doesn’t cause any long term damage though..

  3. My guess is that the wetness is caused by internal rot, travelling down inside the trunk, originating from an old wound higher up the trunk.

  4. A rain spout that is spitting rainwater out onto the tree, or clogged rain gutters overflowing water onto the tree trunk?

  5. It looks like slime flux going down that vertical seem to me. The left half of the tree doesn’t really look that wet, more damp and mossy/lichen-y. You can see by the shoot growth, and by the evergreens on the left, the (warm and drying) sun comes from the right, Could this be the cause, espEcially combined with poor air flow on the shady side? Of course, there might be spray nozzles just to the leftof the pic…..

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