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TOPIC: Back to tree modeling
http://groups.google.com/group/entstrees/browse_thread/thread/fc988a81feef3be8?hl=en
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== 1 of 5 ==
Date: Tues, Aug 19 2008 8:53 am
From: dbhguru@comcast.net

ENTS,

Yesterday I went to William Cullen Bryant Homestead in Cummington, mA to do some crude volume modeling of the largest of the Bryant pines. The huge tree grows apart form the main stand. It is located near the western periphery of the area of large pines. The CBH of the champ on the uphill side is 12.9 feet and it makes 14.1 feet on the downhill side. At mid-slope the CBH is 13.4 feet. The height to a bushy top that has been likely broken more than once in the past is 135.3 feet. There may be a higher point, but there is too much intervening clutter to see well. Besides, with such a bushy top, a higher sprig on an upturned limb could lead to a decpetive trunk volume.
Using a variety of volume formulas that I won't repeat here, the volume lies between 785 and 805 cubic feet of trunk volume. Taking an average of the two figures gives us 795 cubes. However, I think the 805 is reasonable by simple appeal to the overal shape of the trunk. I utilized a volume factor of 0.40 to reflect trunk form, a height of 135.3, and a CBH of 13.4 feet. That combination gives the 805 cubes. So at this point, that's the number I'm going with.
If we add 7% of trunk volume to cover the limbs, we get 865 cubic feet for the entire tree down to ground level.However, our customary method of comparison is just the trunk volume. So the figure is 805 for now. When the weather cools and the mosquito population crashes, I'll do a much more thorough job, using the Macroscope.
The plan for the fall is to model the biggest white pine in each of the major stands in southern New England and to try to do similarly for New Hampshire and Vermont. I'll also include isolated field pines when I can get to them.
So far, in Massachusetts, we have the following pines as members of the 800-cube club.

There are some large open-grown pines that need to be modeled, but the amount of work is daunting unless the pine offers possibilities of being a real champion. Multiple trunks are a real pain. However, we don't want to leave out these big trees and such a tree grows in a graveyard in Conway MA. It will be the subject of a piecemeal, but fairly intensive study effort over the coming weeks. It has at least a slim possibility of exceeding 1,000 cubes, the magic threshold for an eastern conifer.

Monica and I hope to return to New Hampshire on Labor Day and I'm hoping I can reconnect with my firiends David Govatski and Sam Stoddard to see and measure some New Hampshire contenders.

Bob

== 4 of 5 ==
Date: Tues, Aug 19 2008 2:29 pm
From: Larry


Bob, When you buy the new Z8000 Macroscope perhaps you can sell me
your old wore out one. At a well reduced price of course! Larry

== 5 of 5 ==
Date: Tues, Aug 19 2008 2:52 pm
From: dbhguru@comcast.net

Larry,

You can count on it. BTW, it felt good to be able to return to tree modeling. I still want to get down to the deep South and see some of those 30-footers.

Bob

==============================================================================
TOPIC: Back to tree modeling
http://groups.google.com/group/entstrees/browse_thread/thread/fc988a81feef3be8?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, Aug 19 2008 9:27 pm
From: "Edward Forrest Frank"


Bob,

Nice to see you back at tree modeling and preparing to scare people off the list with mathematics.

I have mentioned this before but I want to suggest cylinder occupation again in this context. In the study of the volumes of hemlocks in the Tsuga Search Project a ration could be determined between the actual volume of the tree and the volume of a cylinder of the same height as the tree and of the same diameter as the tree at breast height. What was found was that at the lower end of the scale were outlier percentages representing trees with an abnormally fat base. The unusually large base diameter would yield a lower than average % cylinder occupation. Above this was the normal range of trees with a normal girth to height ratio and generally uniform tapers. Those at the lower end of the spectrum are tree which taper rapidly, while at the upper end of the normal spectrum are those trees that have a slower taper for a much greater portion of the trees height before tapering to a point. The third group of trees were those that had their tops damaged or removed. Since these trees had the profile in their lower portion more representative of larger and taller trees, and a foreshortened top segment representing the least cylinder occupation of any portion of the tree, these tree had an anomalously high % cylinder occupation.

The same could be done for the pine volumes you are measuring. I would expect, if this tree you measured in Bryant Woods has had its top removed and regrown that it would be in the anomalously high outlier or at least in the upper end of the normal spectrum.

What can this tell you? By itself it can indicate that a particular tree has been damaged in the past. it is a measure nor of size of the tree but of shape. I am wondering if there would be a general trend in this value from younger to older trees in an area indicating that the trees basic shape changes with time and as it grows? I am also wondering wonder if there might be a regional trend from south to north that could be determined? The other thing is would there be a clustering of values from trees in a particular environment? For example, would the trees nearer the coast that Andrew Joslin thinks are kept short because of winds, form a meaningful cluster of data points?

This goes along with the idea of plotting three parameters on a triangular ternary plot. Initially I was thinking about plotting girth - height - and average crown spread. This would be a shape diagram for different species of trees, perhaps also show a distinction between young and old trees in a species, and perhaps variations in shape with location or environment. Perhaps the plot of height - girth - and volume would also be interesting. I have a basic ternary plot program posted in the measurement section of the website. Does anyone know or have a macro to create ternary plots in excel?

I certainly think this is something worth pursuing, and you may have enough volume measurements at this point to do some preliminary calculations and plots.

Ed Frank

== 2 of 6 ==
Date: Wed, Aug 20 2008 8:07 am
From: dbhguru@comcast.net


Ed,

Yea, I'm loading up for bear. A set of volume formulas is tumbling around in my noodle getting ready to spill out and find their way into e-mails. I hope that none of the 231 ENTS members will be driven way, but remind the intimidated, that's what the e-mail delete button is for.

You make a compelling case for calculating the percentage of a cylinder occupied by a trunk. Each time you present your ideas on the subject, they become more appealing. ... I particularly like the way it would help to capture the volume for of "decapitated" pines that have recovered enough to present us with very bushy, indistinct tops. Good stuff.

Bob