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Re: Double Trunk Measure >> What If ?

Posted: Tue Aug 06, 2013 9:36 pm
by dbhguru

Good explanation. It helps to know what the inside of these structures look like as I am aware that you do.

I am going to look for examples of trees that are starting to grow together versus ones that are farther along in the process and photograph both types. If we can photograph examples of trees that are at all stages of fusing, then maybe we can settle the issue once and for all.


Re: Double Trunk Measure >> What If ?

Posted: Tue Aug 06, 2013 9:45 pm
by Don
I'd love to see a double pith with single set of concentric must just happen 'briefly'? I've not managed to make just that cut. Actually, it would take a consecutive set of cookies, if I'm reading your description, right?

Re: Double Trunk Measure >> What If ?

Posted: Tue Aug 06, 2013 10:21 pm
by Don
Mario, Will, Bob-
Definitely a head scratcher and a good one to iron out...I've taken the image and delineated it with yellow straight pith lines, blue dashed vertical line, and an estimated red dashed CBH line. If the trees grew up separated from the start and grew in a straight line, the delineated yellow pith line would be correct.
If I understand Will, the more likely route taken by the pith would be something close to the dotted white line?
Feel free to re-delineate the image if you've an idea!
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Re: Double Trunk Measure >> What If ?

Posted: Thu Aug 08, 2013 10:13 am
by mdvaden
Will Blozan wrote:Mario,

I am not sure we are understanding each other but the area of "abnormal" bark and wood (pressure) ridge below the "fork" is clear evidence to me of two stems pushing against each other, fusing, and beginning to coalesce. The ridge is not a result of a large root being there but the interaction of opposing expansion, then fusion, and finally coalescing into a continuous concentric trunk at that point. For the benefit of those not used to cutting trees and looking at the growth, I will illustrate that as time goes on there will be one concentric growth ring with two centers (piths) inside at that level. This happens as the pressure ridges of the two stems come close to touching and the included bark area will be naturally breached, causing the cambium of the two stems to meld into one. However, it is still the result of two distinct stems.

Will (an arborist since 1986)
I can't really see any evidence of bark fusing on that pine.

Cambium can fuse. But included bark just doesn't do that. The breaching of included bark is something that may be possible when bark is thin ... but I think the bark would probably have to be just a few years old. Very thin. Can't put my finger on seeing bark yet that was like 1/2 inch thick, etc., just being bypassed.

That pine appears to an older example of what I've seen hundreds of locally and in the forest, when a individual sapling quickly forks into two or more stems when it's inches or a few feet tall, and continues growth ... both height and girth.

What you propose, I agree could be possible if it happened to trees or bark young enough. But short of an indented included line, I wouldn't be able to tell for certain. Could accept it as possibility, but not ascertained.

Looks like we both agree that the pine is the result of two stems ... but there does not seem to be enough crystal clear evidence that it was two separate trees.

Mario (an arborist since 1980)

Re: Double Trunk Measure >> What If ?

Posted: Thu Aug 08, 2013 10:28 am
by mdvaden
Actually, I find bark to be such a formidable barrier ... this photo is typical of what I find weekly when pruning trees. When bark gets trapped in between, it simply just sits there getting more included every year.

Even with fairly thin bark, it's quite the barrier and impedes any outward growth of phloem or cambium.

Typically, I find that after not too many years, the cambium underneath included bark just "bites the dust" or "croaks" so to speak. Kind of dies-off and just leaves old included bark that barely decays if pinched tight enough to keep air off of it


Re: Double Trunk Measure >> What If ?

Posted: Thu Aug 08, 2013 8:24 pm
by mdvaden
Question !

For all you tree Guru folks, I've got a question, specifically about Pine, especially Ponderosa Pine.

Do you have any photos, or know of any photos, that show self-grafting (inosculation), particularly branch to branch or branch to stem?

I've seen willow, maple, and even a couple of Douglas fir fuse cambium tissue. But it came to mind today that I've never seen it happen out here, with Ponderosa PIne.

So I was curious if anyone has examples in photos.

Think I found one photo for Austrian PIne inosculation online that looks like a real example. ... G_0181.jpg