More modeling   Robert Leverett   Nov 02, 2005 05:44 PST  Will, Jess, Lee, et al:     As we gather more volume data on the white pines and eventually other species, it should be possible to develop standard species profiles to help us better understand how a species growing in a forest environment changes its shape over time. For example, we all see the dominate symmetry of young white pines in a stand. We also see the unruly shapes of field pines. We observes that as forest-grown pines get old, they develop a more columnar form, but some much more so than others. For pines in the 150-foot class, we expect that most of the volume will be in the first 100 feet and all these observations are sound. What we don't know is how to quantify what we see and if there are rules of thumb that we can apply. So, despite all the modeling we have done, there are more loose ends than tied knots. The reason for the plethora of loose ends is that we've had to concentrate on just how to get ball park volumes. But now we have the RD 1000, and with that little beauty comes the possibility of developing models that reflect how volume is built over time. It is just pure unfunded research - no commercial motivations. So progress will be very slow. But progress will come.     A question that I recently posed to myself was this. Is the volume of a trunk from a diameter point of x inches to the top of the tree predictable within reasonably tight boundaries for a species like white pine? Hemlock, etc.? For instance, let's say I scan up the trunk of a tall pine to a point where measurements with the RD 1000 suggests that the trunk has narrowed to 18 inches and from there continuously narrows in a reasonably conical shape. If the visibility is poor and I can't get satisfactory diameter measurements at higher points, can I make a reasonable prediction of the remaining volume? Well, a couple of days ago, I thought I could. But looking at my data, I am puzzled at the patterns I am seeing. Three possible explanations follow.    (1) There is a significant difference in the proportions for younger slimmer pines as compared to larger older one for how much volume can be expected at and above a diameter of 18 inches.    (2) The amount of retained limb mass, courtesy of the pine's growing environment changes trunk curvature sufficiently to create discernibly distinct populations necessitating the introduction of form classes early on.    (3) My data suck (Oh well)    Starting this weekend, I will begin sharing much more detail on individual tree modelings and measurements with those of you on the list. I've already been doing that with a select few off this list, not wanting to drown the rest of you in numbers. But now with Pamela Briggs on the list and finally getting my dear partner Monica Jakuc signed up on Topica, there can be a welcome counterbalance of list topics. So, I won't feel guilty in dumping tons of data onto the list in hopes that more supple brains than mine can help the faithful few tree modelers make sense out of the seemingly endless patterns. Dr. Tom Diggins once observed that ENTS is an incredible brain trust. It only makes sense to make use of it. So beware, folks, the numbers are going to roll. Bob     Robert T. Leverett Cofounder, Eastern Native Tree Society   Home