Limited Species Rucker Indices   Edward Frank   Nov 22, 2004 19:35 PST  Howard, One concern with the Rucker Index we need to figure out, and we touched on it when discussing some of the western forests - is that in some of the harsher environments there aren't ten species of trees from which to create a standard Rucker index. Some examples would be at the extreme northern edge of the taiga forests. Basically the only species present in these areas is spruce. They may be old growth untouched by man, but the 10 tree rucker index is not usable. I think some of the desert communities in the arid and semi-arid west would also have a limited diversity. Another case would be a site is so dominated by one or two species, that even if there are occasional representatives of other species, whatever their height, a false picture of the site would be formed by including the full ten species depth. An example would be some of the redwood forests in the west. Bob Van Pelt wrote: "The low diversity of trees in some Western forests quickly reduces the Index to below 200. Humboldt Redwoods SP, for example, has the world's tallest tree, and 86 trees over 350'. Due to the overwhelming dominance by redwood, the Index drops below 200 after only six species are included!" Oct 29, 2002 These are not likely a problem for the area you are reporting, but I could see a lack of diversity in perfectly untouched old growth on some of the knobs - the dwarf forests I have been thinking about lately - in both the Catskills, in Mass, and other areas of New England with similar topography. Ed Frank RE: Kaaterskill Falls-Catskills-NY   Robert Leverett   Nov 23, 2004 10:46 PST  Ed, Howard, Will, Dale, Lee, John, Don, et al:    In preparation for next year's Black Hills excursion, I've been toying with the idea of the Rucker Index tied to a different number of species. We might have a RI5, where 5 represents the number of included species. I had thought about suggesting something of this sort once before, but at the time, it sounded like over-kill. Then WNTS was born. Don Bertolette needs to have the primary say-so on the approach used to compute Rucker indexes for sites in the Rocky Mountain West, an approach based on the number of available species seems natural.          Bob RE: Rucker index   Lee E. Frelich   Nov 23, 2004 11:38 PST  Bob et al.: Yes, you can do a Rucker3, R5, R10 or any number of species you want. You can always pare down the number of species in a diverse forest so that it can be compared to a less diverse one. I have already been using it in lectures at the University of MN. Lee Re: Kaaterskill Falls-Catskills-NY   Don Bertolette   Nov 23, 2004 13:20 PST  Bob- Ed's right, relative to the NE, the forests of the NW and SW are often depauperate species-sise. I can think of exceptions to the rule (I've shown you some classic mixed conifer old-growth with 6 or 7 species that could put up some big numbers. My guess is that we're going to find that East is East and West is West and only the Treeti shall meet at the Uintahs shall they meet... (quoting from a document some months past... "this summer's past trip that included the Black Hills, I realize that there is a story to be told and modified Rucker indices to be calculated (forget about a 10-species index). I'll likely spend a good deal of time in the Utah Wasatch and Uintahs also.") -Don Re: Kaaterskill Falls-Catskills-NY   fores-@earthlink.net   Nov 23, 2004 13:52 PST  Even for the Northeast, 10 species sounds like quite a lot. Also, if we are truly interested in growth potential, once you past the first 4-5 species, it would seem that there might be a number of tracts where the remaining 5-6 trees would be hangers on and less adapted to the particular microsite? Maybe a RI10 and RI4 should be kept for everything (where possible), along with the HRI. (And while I'm at it, just to make a complete complicated mess of everything, fat diameters trees are also very impressive and seem to me as important as purely tall ones, perhaps a fatness index should be kept along with the Rucker height index, restricted to count only in forest (no field) grown trees having single trunks to say 20' or greater above ground, and just to add even more, something like the American forest great trees list, except with the restriction that the trees be tall, columnar, forest grown types, and that crown spread counts for nothing, front yard and field trees can be very nice, but there are much different breed than forest grown trees, which I think should have there own list.) An Appalachian mixed mesophyetic forest might easily have 10 solid species, but otherwise, it seems perhaps a stretch. I can think of some fabulous old-growth tracts in the Adirondacks that are so sugar maple dominated, that beyond some scattered white ash and yellow birch I don't recall seeing all that much else, and yet the tract was tall and impressive, clearly OG, but I'm not sure if it could qualify for the 10 species rucker, perhaps there are 10 species there, but I have my doubts, and even if so, it would surely have its index unfairly cut down quite drastically. Then again my tree identification skills are weak, and I haven't really paid enough attention, perhaps. Even my backyard tract back in NJ, which has some nice trees, quite well grown back and significant pit and mound topography, I can think of sugar maple, two oaks, white ash, tulip, ironwood, hemlock (1 single tree), beech and maybe one other. That's 9. I'm not sure if there is a 10th species in the tract, and yet its quite a nice tract, although the older part is quite small in acreage, which is the only part I was counting, it would go beyond 10 species if I extended it to encompass the extensive surrounding woods (some parts of which are also quite mature), so perhaps it is simply too small a tract to make a fair test out of, although the additional species would be picked up from areas with different growing conditions. RE: Rucker index   Edward Frank   Nov 23, 2004 18:50 PST  ENTS, I tried to address the terminology of using something other than 10 species to create an index variant. The post was dated April 25, 2004. http://www.nativetreesociety.org/measure/all_ruckered_out.htm Certainly it is easy to create a shortened version of the index for comparison between areas with less species diversity to those with a higher diversity. Lee using this format in his lectures is excellent. One reason that I like the ten species requirement for a standard index is that it requires a certain depth of measurement. A site is examined in more detail in the attempt to find tall specimens of all ten species, rather than concentrating on just those few species you expect to produce the tallest trees. In the acre or so of land my home sits on, I can list over a dozen different species that could be measured for an index of "My Backyard." I think if these additional species are present, it is important to measure them to adequately represent the diversity of the site. I have argued in the past that if possible, I would like to see an RI20 including twenty species if that many are present. In some cases as have been cited by others and myself there simply is not a great enough diversity to include 10 species, or possible inclusion of a full ten species would provide a false impression of the site. In these cases a RI of less than ten is appropriate. I have also been considering how we can use our height measurements to look at forest composition and structure from the uppermost canopy to the herbaceous layer on the forest floor. I will address this in another post in a few days. Ed Frank Home