A hemlock harangue!

[Don]

Without a really insightful narrative of how this happened, I'm inclined to fall back on good photo-chopping technique...the challenge? How do we measure it, by existing, or current measuring guidelines, and is it single-stem or multi-stemmed?
[courtesy of Ed Frank - Facebook NTS Group, photo credit to GSMNP via Richard Barry]

               

                       

                       

Great Smoky Mtn. National Park hemlock

               

               

[Rand]

I'll stick my neck out.  It looks like two separate trees that grew up together.  A side limb of the right hand tree collided with and fused with the tree on the left.  Meanwhile the tree on the left (or maybe the tree in the background) outgrows and overtops the tree on the right .  The top of the right hand tree dies and rots away, leaving its fused limb behind.

[Don]

A better guess than mine!
I can draw up pith lines only so far...then I just can't fashion what the cross-section of the two going into one, say in 12  one inch thick pie slices going from initial contact of the two, as they appear to "...go into one".

[mdvaden]

I know how I'd measure it. And I'd make up a special rule just for it.

But I'd follow the center of the right trunk and the left trunk, each one, up the middle for 4.5 feet, even if it meant bending the corner rather than just going straight up 4.5 ft. above grade. It would be 4.5 feet along the length of each trunk. Then I'd measure the circumference of each one at that point and combine the square inches of cross section together.

[Don]

So, Will/Mario/Rand/others-
I still can't picture what's going on with that hemlock, where I've delineated a red line in image attached.
I can imagine them as two separate nesting pairs of concentric rings, each around a central pith, having grown together, and then with the passing of years and continued proximity, filling in the void between them, until subsequently they are enclosed growing as two stems in parallel.

Can you draw or fully describe what you perceive the cross-section taken at the redline would look like, specifically in terms of the annual rings and pith?

               

                       

                       

[courtesy of Ed Frank - Facebook NTS Group, photo credit to GSMNP via Richard Barry]

               

               

[Joe]

I suggest it was a single tree. The top broke or was cut. Below that level, it had only 2 living branches- which then shot up and fused. I doubt 2 separate trees could fuse that way- but I don't know for sure. I'd be surprised if it could happen.
Joe

[mdvaden]

I suggest it was a single tree. The top broke or was cut. Below that level, it had only 2 living branches- which then shot up and fused. I doubt 2 separate trees could fuse that way- but I don't know for sure. I'd be surprised if it could happen.
Joe

The could have rubbed and fused prior to the breakage. I've seen variations of merged trunks in the past but this is the only one of this sort of double branch sort. They are pretty rare out this way.

Wherever the red line is, that's as good as any suggestion probably.

Reminds me of this, but this certainly had to be two trees, not two branches.

[Don]

Mario-
My intent by placing a red line, wasn't to suggest where one should measure the dbh/cbh...I was trying to elicit your idea of what the cross-section would look like at that location...more to the point, would it be to sets of pith/nested concentric annual rings, squashed together due to their increasing proximity?  Or?