Buttress measures   Roman Dial
  Sep 27, 2005 21:09 PDT 

While we were in Borneo we had a Malaysian research assistant (RA) who
knows the tree species scout around for more big trees while we were
climbing found big ones. We sent him out with a tape to get measure of
the buttreses.

I suggested he measure the buttresses not at breast height but at about
300 cm above ground as that captures most of the impressiveness of these
buttreses but avoids the roots which can be a foot thick above ground,
too. Also the tape went from buttress to buttress, not into the trunk,
so that this was in essence a minimum convex polygon that enclosed the
buttressed base of these trees (the biggest was 32 m around -- that's
more than 100 feet around!).

What I wanted was two fold: (1) using a rather weak correspondence
between buttress and tree height (for 28 big trees I got an r-square of
a bit over 0.5, and generally trees over 15 m around were also over 65 m
tall) I wanted to use the RA to help us sniff out big tree groves and
(2) an attempt to get a measure that captures the impressiveness of
buttresses without a huge amount of effort. Something like a tropical
version of the stanfar index that relies on the two impressive measures
of a tropical tree: buttresses and height

Do the ENTS out there have any suggestions or does buttress measuring
seem too dodgy?

Re: buttress measures   Bruce P. Allen
  Sep 28, 2005 08:00 PDT 


Based on measuring diameters on >10,000 cypress and swamp and water
tupelo buttresses in South Carolina, I don't think there was a
consistent relationship between buttress size and diameter above
buttress - and presumably height. Some of the larges buttresses had
the very small trunks.

Re: buttress measures   Edward Frank
  Sep 28, 2005 08:37 PDT 


I am in favor of collecting a variety of measurements. At this point I am
not sure what, if anything, the butress measurements mean. But on the other
hand any significance likely would not be found until a data set was

The cbh vlaue is good for working on moderate sized trees to determine trunk
diameters. It is generally above the root flair, but not so far up the tree
that trunk tapering has affected the measure to any great degree. For large
trees with large butresses or trees with big butresses like bald cypress
this value is still within the area of root flair - trunk diameter
measurements equivalent to normal cbh would need to be taken well up the
trunk - maybe 6 to 10 meters. For dwarf trees, shrubs, or other very small
trees, cbh is much too high to represent the diameter of the trunk. I have
propsed before that these should be taken at 1 foot or above root flair
whichever is higher.

Bob Van Pelt has made detailed maps of the butress footprints of some of his
large trees. One problem we have been considering, even with our <200 foot
trees is how to determine where the base point of the tree is located. I am
sure that can be an even bigger problem with these bigger diameter

So all in all, collect the measurements and see if they lead anywhere. I
would also encourage you to participate in the ENTS group. We are trying to
expand our areas of interest beyond the eastern US.

Ed Frank
Re: buttress measures   Edward Frank
  Sep 28, 2005 09:00 PDT 


That is quite a few butress measurements. Did you measure both butress and
trunk diameters for all of them or just some? Were these taken as part of
timber surveys over the years? It would be an interesting data set to see

RE: buttress measures   Robert Leverett
  Sep 28, 2005 09:44 PDT 

ED, Roman, Bruce, et al:

Since undertaking a mission to measure the volumes of the largest
white pines and hemlocks in the Northeast and later across the entire
range of each species, including good buttress measurments has risen to
near the top of my challenges. Studying and measuring the buttressing
for trees growing on steep slopes versus in flat wet areas and the
tendency for some species to develop conspicuous buttressing for even
medium-sized trunks should keep me off the streets for the better part
of the fall and winter.

I was fascinated by the heavy buttressing of the Cherry bark oaks in
Congaree, but a similar, though more subdued form of the buttressing is
evident on the American, slippery, European, and Siberian elms here in
western Massachusetts. It appears that there are archetypal buttressing
forms that cut across a number of species.

For me, measuring buttressing ties appropriately into the overall
challenge of volume modeling. But this is one time I'm happy to be in
New England. I take one look at a photo of a huge, heavily buttressed
bald cypress and it makes me want to turn tale and run. Roman, I can't
even imagine the impact those great tropical trees must have had on you
and your team.

Re: buttress measures   Bruce P. Allen
  Sep 28, 2005 12:05 PDT 


I was interested primarily in the diameter, the
buttress dimensions were simply an
observation. The trees were located in 6 1-ha
permanent plot sampled multiple times in two flood plains.

RE: buttress measures   Roman Dial
  Sep 28, 2005 18:55 PDT 


That is a good sized data set, for sure! And it is certainly true that
some tall trees have relatively smaller buttresses in the tropics, too.

Here's a paper I just looked at that gets about the same sort of
r-square between buttress diameter and height for 300 individuals in the
Amazon (Asner et al. Biotropica 34: 482-492) that I got for my one-tenth
the sample size in Borneo.

The bigger issue really (for me) is coming up with indices that capture
the "coolness factor." I really like the Rucker index because it's
simple and it captures some of how neat a forest might be. A neat forest
(for me) is a place where I wander around and see a variety of amazing

Two ways stand out of getting amazing trees. One is visiting timberline
where often the diversity in species is very low but the diversity in
forms and their "presentation" (against rocks, in meadows, creeping,
wind blasted -- the huge variety of krumholtz) is spectacular -- each
tree is so individualistis in morphology. The other way is a forest of
just big trees of a variety of different types.

I have neck problems -- too many years of looking up (first rocks, then
mountains, now trees) -- so I do like big girth and especially wild
buttreses. Buttressing in the primary lowland tropics of Borneo is a
delight to experience (I am also partial to high volume and twisted
lianas, but that's a differnt story).

What I am trying to get to in a long winded way is this: I want to
combine height with buttressing in tropical trees to come up with a
"wow" index (and the words "wow", "beast", "wall of wood", "giant",
"holy cow", "oh my god" don't satisfy my quantitative/analytic side
sufficiently). My hunch is that the AF Point system for identifying
Champions is a temperate version of this same desire. A numerical means
of capturing the "wow" factor of big trees using CBH, height, and crown
spread. I want to use buttresses together with height to calculate a
"wow" factor for tropical trees.

Indeed I sense many ENTS out there, especially those playing with their
RD 1000's are doing this with wood volume. I know BVP has infected Brett
Mifsud with volume as the rawest of the raw "wow" factor calculations,
but as yet most of us don't have the experience measuring volume for the
numbers to have the same meaning as girth, height and spread, the
classic combination.

Butresses   Edward Frank
  Oct 02, 2005 17:51 PDT 

Bruce and Roman,

The large root butresses on trees like the bald cypress are obviously an
adaptation to the trees growing in a swampy environment to provide
additional stability for the tree. The potential for the butresses is
genetic, but I wonder to what degree the actual environment influences the
size of the butress. Are the butresses larger in areas where the soil is
less stable, suportive, or strong? I am always amazed at the small size of
the root ball turned up when large trees are blown over by the wind. Does
swaying of the trees caused by wind stimulate the enlargement of the root
butress?   Bruce you have observed that the size of the butrees does not
seem to be directly related the size of the trunk - what is causing the
differences in butress sizes? Roman you cited a paper in which a
relationship between butrees and trunk size was found in the Amazon. Is
whatever variable that is causing the butress size variation in the swamps
of the American southeast exhibit less variation in the Amazon sample set/?
Do you any specutlation on why this is the case?

Ed Frank
RE: Butresses   Roman Dial
  Oct 02, 2005 21:08 PDT 


My answer will not be very satisfactory!

First, let me digress on philosophy of science of ecology. In general,
there seem to be two types of ecologists. The first looks at the
ecological equivalent of a rainbow and says, "Look at the incredible
number of colors in a rainbow. The closer we look the more colors we
see." Another ecologist looks at a rainbow and says, "Wow, every time
the sun comes out while it's raining we see a rainbow. That's really

One ecologist concentrates on the incredible diversity, the other on the
repeating patterns.

My very brief treatment of Borneo buttreses, using a very-very, very
crude and perhaps dodgy measure (tape stretched around the perimeter at
about 1 foot ~ 300 cm above ground) gives a log-log plot of height in
meters as proportional to the quarter power of the dodgy measure of
buttress diameter. More than half the variability in height is
correlated with variability in the dodgy buttress measure. This is the
"tedious expression of the obvious" statement that taller trees are
bigger around at their supporting surface.

So now, those of us who are amazed at the infinite colors in a rainbow
are mostly interested in the other half of the variability in buttress
sizes that are not "explained" by tree height. It is the departures from
the regression line that take us back out into the field to find out
when do short trees have big buttreses and when do tall trees have
skinny ones.

Meanwhile the others of us are blown away by the fact that the quarter
power shows up as an exponent on buttress diameter when figuring tree
height, since that quarter power exponent shows up all over ecology,
from animals to plants, from vascular networks to ecosystem properties.
We think that it must be a fundamental property of life that moving
material through a (fractal) branching network leads to a constant
relationship betwen how big around something is and how long it turns
out to be.

See, I warned you! Not very satisfactory.....

Re: Butresses   Bruce P. Allen
  Oct 03, 2005 07:13 PDT 


The biggest factor affect buttressing in cypress and tupelo is the
depth and duration of flooding. Tupelo seem to have the lowest
correlation between buttress size and stem diameter. I have photos
of tip up mats 25 feet high but no more than 2 feet thick, rooting
depth is the key. I have almost never seen cypress tip up in spite
of very soft substrates.

RE: Butresses   Willard Fell
  Oct 03, 2005 08:15 PDT 
Here's a photo I took yesterday where the water was about 4 foot down
and you can see the relationship between the water level and the butt
swell on pond cypress.

parrish_pond.jpg (43003 bytes)