It was with no surprise that I read that the coast redwood tree measuring community is ‘stumped’ with the conundrum of determining what is an" individual tree". Bob and I struggled for more than two years to arrive at a solution. Your initial post in the NTS BBS showed a lot of thought and it’s taken me several readings to get my head around it, and then I still have questions.
Part of my confusion comes from finding the right words to describe what we all mean. The other thing is we have been wearing our AF Measuring Guidelines Working Group hats for so long that we have to remember that we share words and phrases that may not fully mesh with your usages.
And another point of potential confusion...when speaking of national champion trees, we speak of their 'bigness' in terms of formula points from a configuration of height, circumference, and crown spread units. When the redwood measuring community speaks of giants, it's measure is volume, with base, iterations, adventitious branching, etc. in units of cubic feet, or meters.
My academic preparation is neither as recent, nor as specific as yours, so please excuse me if I express what may seem to be simplistic views. When you say fusion, can I assume that you are referring to two trees (in this case, of same species) that grew from separate sources (whether seeds, burls, etc.) in close enough proximity that they physically “met”, then extruded cambium/phloem away from contact zone….and then in the process of growing upwards, also grew “together” with bark enclosing the base in a manner that it’s difficult to assess, after significant time passage, that it was in fact two stems?
If that’s the case, then your formula for Volume Calculation makes sense to me, at least in that the formula would approximate what each stem ‘offered’ in the way of total volume, proportioned by respective cross-sectional areas, in your case, at the 1/3 total height level.
Given that the proportion at that level is representative of the base proportions, this solves the problem of making sense out of the base, which may be obfuscated by centuries of growth around the two stems. To the extent that such measurements at 1/3 total height (or wherever the two stem emerge) are possible either by direct measurement accomplished by tree climbers, or remotely by reticled monocular/binocular, this has great promise.
It would seem to get messy down below, with ‘wood’ extruding away from contact zones in somewhat irregular fashion, but certainly a better estimate than any other I can envision short of an arboristic ultrasound mapping of tree densities…I have seen them used on ‘normal’ sizes of trees, but would imagine that they’d have to power up their analytics, and lengthen their circumferential band of signals.
If I have “barked up” the right tree in my read on your post, it would be consistent with what we in the Measuring Guidelines Working Group at American Forests are endorsing, in trying to differentiate single-stem trees from multiple-stemmed trees.
In no small part, this is a physiologically-based differentiation, in that assumptions come from plant physiology…in the case of gymnosperms and angiosperms, “a” tree is grown from “a” seed, the a single apical meristem extends upward, and with each successful growth increment creates a concentric annual (most of the time) ring. Subsequent growth years leave behind a pith, as the apical meristem ‘points the way’ upward, repeating the annual increment in an eventual series of nested annual rings.
Drawing from the Wood Science I was taught at Humboldt, the primary assumption is that trees, in the absence of external input, will grow up straight and with as near circular a cross-section as they can. Most of affecting external outputs can be seen, detected or inferred (soil movement, obstacles within proximity, canopy openings, gravity, etc.). Recalling how gymnosperms and angiosperms respond with compression wood and tension wood respectively, provides the observer/delineator with cues to the alignment of the pith relative to the eccentricity of the cross-section.
In a reverse-sort-of-logic manner, taking your cones diagrammed in your post, and running an assumed central axis (where pith would be, unless external input were noted) that went from vertex to the base (both equiangular and equidistant), one can make a reasonable guess how far away the pith lines would be at ground level.
Wouldn’t these be representative of the distance between their two seed sources?
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Grand Canyon National ParkBJCP Apprentice Beer Judge
View my Alaska Big Tree List Webpage at:http://www.akbigtreelist.org