Buttress measures   Roman Dial   Sep 27, 2005 21:09 PDT  ENTS: 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? Roman Re: buttress measures   Bruce P. Allen   Sep 28, 2005 08:00 PDT  Roman, 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. Bruce Re: buttress measures   Edward Frank   Sep 28, 2005 08:37 PDT  Roman, 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 collected. 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 specimens. 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  Bruce, 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 compiled. Ed 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. Bob Re: buttress measures   Bruce P. Allen   Sep 28, 2005 12:05 PDT  Ed, 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. Bruce RE: buttress measures   Roman Dial   Sep 28, 2005 18:55 PDT  Bruce, 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 trees. 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. Roman 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  Ed, 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 cool." 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..... Roman Re: Butresses   Bruce P. Allen   Oct 03, 2005 07:13 PDT  Ed, 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. Bruce 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.   Home