Posted: Sat Feb 18, 2017 6:24 pm
by Don
I'd like to open up discussion to a broader spectrum of tree species, than just redwoods, if you folks don't I'm in the 'business' of trying to find as 'standard' a rule as is possible for almost all species.
For example, in an image of two ponderosa trees that Mario offered up some years back, I have taken the liberty of delineating it, based on my understandings of the physiology of tree growth, as follows:


Two "fused" ponderosa pines, image is courtesy of Mario Vaden

The orange lines represent the assumed pith lines, extended down from the central axis of each ponderosa pine here. The curvature that starts roughly about waist high on Mario's friend, represents the curvature of the pith lines as the two trees pushed against each other as they grew together. The red dashed line represents the Zone of Extrusion, where the cellulose, lignin, cambium and phloem extruded out with each annual increment of growth. While I don't have an image of the back side of these two ponderosas, I would expect a very similar Zone of Extrusion on the back side. These trees have begun the process of inosculation, and after another hundred years, I would predict the bark would attain a uniform appearance that one would expect of a single tree, and a generally circular apparent cross-section. The yellow lines represent the two locations where the diameter could be tape wrapped, with respective heights that they were taken at.
What sayest you?