How to deal with buttressed tropical trees

General discussions of measurement techniques and the results of testing of techniques and equipment.

Moderators: edfrank, dbhguru

User avatar
dbhguru
Posts: 4464
Joined: Mon Mar 08, 2010 9:34 pm

How to deal with buttressed tropical trees

Post by dbhguru » Fri Jan 01, 2016 11:20 am

Ents,

My friend Don Bertolette's recent Hawaii visit reminded me of how far we have to go in figuring out how to measure and judge big buttressed tropical trees for the champion tree competitions. DBH and CBH do not work. Period. However, it is turning out that there are ways for estimating volume. Some weeks back Don Bragg sent me a copy of the following article;

On the geometry and allometry of bigbuttressed
trees - a challenge for forest
monitoring: new insights from 3D-modeling
with terrestrial laser scanning
authored by

Nils Nölke (1), Lutz Fehrmann (1), I Nengah Surati Jaya (2),
Tatang Tiryana (2), Dominik Seidel (1), Christoph Kleinn (1)


The authors propose the following equations for computing volume below the buttressing of tropical trees.
VbEquation.png
DAB is diameter above buttressing, Hdab is height from ground to DAB, and fb is a buttress form factor that averages to 1.53 for the trees they include in their small sample. The measurement of DAB is a natural for the reticle, and we have use of the reticle zeroed in (reference the latest edition of the Bulletin of the Eastern Native Tree Society).

The above mentioned article plus two extremely detailed papers by Drs, Steve Sillett Bob Van Pelt, and others make me wonder if the DAB approach would work for our less complicated, but still strongly buttressed eastern trees such as cherry bark oak bald cypress, and even American elm.

Our approach vis-avis the champion tree program might be to: (1) compute regular big tree points for the part of a heavily buttressed tree above the buttress, (2) compute buttress volume, and (3) add the two measures together. This would be a far easier process than trying to compute volume for the entire tree, which in a tropical setting could be virtually impossible for most tree measurers. There would be some judgment over the point where buttressing ended. We would need to develop guidance for that. Just thinking out loud.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

User avatar
Matt Markworth
Posts: 1302
Joined: Fri Nov 23, 2012 8:41 pm

Re: How to deal with buttressed tropical trees

Post by Matt Markworth » Fri Jan 01, 2016 7:23 pm

Bob,

To get more examples, the next time I see a tree with sizable buttresses I'll take enough photos to do a 3D model and then use Meshlab to calculate buttress volume. Also, for higher up measurements, I have a Vortex Solo R/T 8x36 on order and will start to practice with it when it arrives.

Matt

User avatar
Bart Bouricius
Posts: 562
Joined: Sat Apr 17, 2010 9:41 am

Re: How to deal with buttressed tropical trees

Post by Bart Bouricius » Sat Jan 02, 2016 6:02 pm

Here are a few examples to help the thinking process. Many of these are from past posts, but I wanted to put them together for comparison. These are all from Costa Rica and Peru. One problem is that when large buttressed trees are in the open they tend to be engulfed by vines and epiphytes which is basically a separate but overlapping issue. The reticle does not help to see through this foliage.
e DSCN0348.jpg
02-BigTreeKapokPeru2143.jpg
DSCN4358.JPG
IMG_fig 6564.jpg
IMG fig2_6748.jpg
for Paul3Jav IMG_0855.jpg
Attachments
04-Bart-Sarapiqui-Tree-No-1_P2862.jpg

User avatar
Don
Posts: 1560
Joined: Tue Mar 09, 2010 12:42 am

Re: How to deal with buttressed tropical trees

Post by Don » Sat Jan 02, 2016 7:19 pm

A couple of thoughts...I'm now seeing the buttressed tropical trees a little differently...in a variation on forestry and rocket science, I'm now seeing them as rockets, with the stabilizing fins at the base...I have the sense that if we shaved off the 'fins' we'd find a fairly columnar bole. If not, at least quantifiable by a factor eventually associated by species/region.

Responding to Bart's comment of other plants attaching/growing over, that makes things pretty much unworkable once you can't get to the 'inner tree'. Several of those (Koa, I think) were enclosed by strangler figs/etc. to such an extent, that I couldn't physically get within perhaps as much as 10' of the "inner tree". I don't think there will be soon a solution for those...

Attaching a couple of images of such a 'beast', the first fairly close, the second taken far enough back to see the a perimeter 'flush' that in time could create an 'enclosure' perhaps 100' across...
-Don
Kauaii Strangler.jpg[/attachment} [attachment=1]Kauaii Strangler.jpg
Attachments
Strangler Perimeter.jpg
Kauaii Strangler.jpg
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Science Center
Grand Canyon National Park

BJCP Apprentice Beer Judge

View my Alaska Big Tree List Webpage at:
http://www.akbigtreelist.org

User avatar
Will Blozan
Posts: 1153
Joined: Fri Mar 12, 2010 7:13 pm

Re: How to deal with buttressed tropical trees

Post by Will Blozan » Sun Jan 03, 2016 9:47 am

Bart,

With enough samples of an individual species of tree the form factor will be all that is needed to arrive at a reasonable minimal estimate of volume in the buttresses and under epiphytes. Only two measures would need to be taken- which would be two likely to be obtained with a little diligence for a sighting position. DAB and HAB.

Don,

I am not sure what you mean by "shaving off the fins". I have never seen a tropical tree that has a cylindrical bole "underneath" the fins. The trunk just morphs into supportive tissue. Soome of the biggest trees Bart, Jess and I measured in Panama were but inches thick at midslope. But DAB was 6 feet or more.

Will

User avatar
Will Blozan
Posts: 1153
Joined: Fri Mar 12, 2010 7:13 pm

Re: How to deal with buttressed tropical trees

Post by Will Blozan » Sun Jan 03, 2016 12:13 pm

Here is an example of a tree reticled by Jess Riddle and I in Panama last March. It was a tree we could see from our camp which made access pretty easy. It is a Cedrela odorata, locally known as "Cedro", and grows in Amistad International Park.
As viewed from camp
As viewed from camp
Top detail
Top detail
Me at base dodging bullet ants
Me at base dodging bullet ants
Conventional measurements are 191.8' tall (53.5 m) and 27' "cbh" (8.23 m). Obviously, the tree is buttressed and the diameter overstated hugely. For the initial volume measurement we only measured diameter at 24.8' (7.56 m) above midslope and higher, since that is were it was more or less cylindrical. Diameter here was 5.42' (165 cm), and from here we carried a column down to midslope. At 108.3' the tree forked from 4.7' diameter (143 cm) into two identical leads 3.27' wide (99 cm), both reaching max height.
Max at lowest available "mid-slope"
Max at lowest available "mid-slope"
Approximate location of DAB
Approximate location of DAB
With a column from DAB (diameter above buttress) the lower bole scales 572 cubic feet (16.2 m3) of wood and the entire tree without branches is 2,681 cubes (75.92 m3). With a form factor suggested in the paper in this post, the average factor (1.53) would increase buttress volume to 3,165 cubes (89.6 m3). Big difference!

Ok, now let's use the standard "CBH" wrap (which, BTW, was almost 15' above midslope... Total volume now is 3,533 cubes (100 m3). Obviously, mostly air space!

So in summary, basing tree volume on DAB short changes a tree such as this by over 10%, assuming the form factor is close to reality.

-Will

User avatar
ElijahW
Posts: 803
Joined: Sun Jun 26, 2011 4:04 pm

Re: How to deal with buttressed tropical trees

Post by ElijahW » Sun Jan 03, 2016 9:03 pm

Hey, Will, cool tree. The only species I've seen that come to mind with that kind of buttressing in the eastern US are elms and cypress. Will we hear more about this trip?

I bought a Solo Vortex R/T a few weeks ago, but have not used it on a tree yet. I've been reading a lot about how to figure trunk volume, and Bob's spreadsheets should help quite a bit. I can see why you like the Vortex; it feels great in-hand and is easy to focus.

Sorry to get off-topic, but I really enjoy seeing pictures of tropical trees. I've read all of Bart's posts, and look forward to anything new coming out of the South. Thanks,

Elijah
"There is nothing in the world to equal the forest as nature made it. The finest formal forest, the most magnificent artificially grown woods, cannot compare with the grandeur of primeval woodland." Bob Marshall, Recreational Limitations to Silviculture in the Adirondacks

User avatar
Will Blozan
Posts: 1153
Joined: Fri Mar 12, 2010 7:13 pm

Re: How to deal with buttressed tropical trees

Post by Will Blozan » Mon Jan 04, 2016 6:58 am

Elijah,

Yes, much more coming. The Vortex Solo is awesome. Do you have it on a tripod? Absolutely essential for volume work.

Cherry bark oak and sometimes shumard would be good candidates as well.

Will

User avatar
ElijahW
Posts: 803
Joined: Sun Jun 26, 2011 4:04 pm

Re: How to deal with buttressed tropical trees

Post by ElijahW » Wed Jan 06, 2016 11:08 pm

Will,

I don't have a tripod yet, but it's on the list. I'm looking forward to seeing some more giant tropical trees.

Elijah
"There is nothing in the world to equal the forest as nature made it. The finest formal forest, the most magnificent artificially grown woods, cannot compare with the grandeur of primeval woodland." Bob Marshall, Recreational Limitations to Silviculture in the Adirondacks

User avatar
Don
Posts: 1560
Joined: Tue Mar 09, 2010 12:42 am

Re: How to deal with buttressed tropical trees

Post by Don » Wed Jan 06, 2016 11:27 pm

Matt-
After reading some of the Sillet, et al papers dealing with buttresses and how to quanitify them, I had some ideas that I thought I'd run by you, in the context of hinting at some helpful measurements you might include in your 3D modeling efforts. It could be really helpful to have:
1)good root/base foot print coverage,
2)a dbh measurement, plus, knowing that the tape would basically describe a 'chorded' polygon in cross-section, a minimum/maximum/average distances from the chord-bisecting perpendicular lines going to the bole),
3)height to top of buttress. (defined by first insignificant difference between successive 50cm perimeters above buttress).
It's hard to word these, you've undoubtedly have questions, do not hesitate to ask for further clarification.
If there's some way to integrate these locations in the actual 3D meshlabbed image, that'd be great!
Personally, what you're working on is my idea of where measuring of non-standard tree forms for national register candidacy will be in the future. Don't know about you, but I find this exciting!
By the way, I see the reticled monocular, when mounted in a manner such as Will Blozan does, as an essential tool of the non-standard form tree measurer...
-Don
Matt Markworth wrote:Bob,

To get more examples, the next time I see a tree with sizable buttresses I'll take enough photos to do a 3D model and then use Meshlab to calculate buttress volume. Also, for higher up measurements, I have a Vortex Solo R/T 8x36 on order and will start to practice with it when it arrives.

Matt
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Science Center
Grand Canyon National Park

BJCP Apprentice Beer Judge

View my Alaska Big Tree List Webpage at:
http://www.akbigtreelist.org

Post Reply

Return to “Measurement and Dendromorphometry”