Regional Tree Divisions   Robert Leverett   Apr 27, 2006 11:33 PDT  ENTS, On a more general theme, for comparably sized areas, the southeastern sites lead the northeastern sites by about 20 points. From the data we now possess, that appears to be a fairly stable differential. Over an ever increasingly wide range of species, the differential will likely float between 17 and 23 points. At this point, a fair question is where do we want to draw the north-south line? A reasonable spot would be at 40th parallel. Any line would be arbitrary, but 40 sounds about right to me, even though it doesn't match Pennsylvania's southern boundary? Anyone care to vote on the dividing line for ENTS purposes? Bob Robert T. Leverett Cofounder, Eastern Native Tree Society Regional Tree Divisions   Robert Leverett   Apr 28, 2006 05:06 PDT  Scott,    One objective of our lists and big tree/tall tree analysis is to develop maps that show the potential of a species across its full range. I would say that if the dimensions you recorded for that pine demonstrate its potential within that geographical area, then your data is extremely valuable and it should be included in a regional list of maximums.  Bob Re: Regional Tree Divisions   Edward Frank   Apr 28, 2006 16:51 PDT  Bob, Breakdowns of naturally occurring phenomena and features should be based upon natural break points in the continuum. I feel, if you are looking at zones based upon latitude, there really are three zones for consideration in the eastern US. I would break the data into these three sets. A northern zone: Including NY and New England, Michigan, Wisconsin, and Minnesota. A Mid-transition zone with mixed forest types: Including PA, OH IN, IL, MO, KY, WV, VA, MD, DC, DE, NJ A southern zone: NC, TN, ARK, LA, Miss, AL, GA, and FL (except for extreme southern FL). Again all of the forest types intermingle, but the political boundaries cited seem to match reasonably well to the three zones I delineated. When the boundaries are variable nortth and south with intermingling, a political boundary that matches fairly well is as good as a lattitude boundary that doesn't match any better. There are also some practi cal and common usage considerations which would favor political boundaries also. The basic boundaries of the forests are not so much north south as ne-sw and linked to geographical/climatic zones. There is a northern zone as defined above, Appalachian Mountains, Western Plateau regions, Midwestern Plains, and Southern coastal plain. Ed Frank RE: Regional Tree Divisions   Lee E. Frelich   May 01, 2006 05:53 PDT  Bob: Ed's zones correspond roughly to those proposed by some researchers who did common garden analyses of white pine seedlings. Who knows whether height patterns will be the same. I am not going to advocate any grouping until I do a variety of multivariate analyses of the data. Lee   Ed,    Good food for though. Lee, what do you think about Ed's three zones? Bob RE: Regional Tree Divisions   Edward Frank   May 03, 2006 14:25 PDT  Bob and Lee, My suggestions on how to break down the zones for use in making comparisons are not based on any sophisticated type of analysis. I looked at a map depicting the major forest types in eastern United States and choose them based upon those groupings. My northern Zone included most of the Northern Hardwoods, Boreal Forest, Northern Savanah, and some maple-basswood The Middle zone included many different forest types, both northern and southern and included most of the northern pine-oak, most of the beech-maple, much of the oak-hickory, and some mixed Appalachian among other fragments. The Southern Zone included almost all of the Southern hardwood, a big chunk of the Oak-Hickory, Mixed Appalachian, and Southern Mixed Pine-Oak. This seemed a reasonable compromise to delineate the zones. If only two zones were to be used I would go with southern border of PA, Ohio, and Indiana to be the demarcation line. Ed Regional lists   Robert Leverett   May 04, 2006 04:15 PDT  Ed,    It's a tough call to make under any circumstances. I had opted for a simple way out with just two zones, but certainly recognize that altitude, proximity to large bodies of water, and annual precipitation skews what otherwise might me a clearer picture when just considering latitude. In an aggregate sort of way, species distribution maps reflect the composite influences of these variables.     Our discussion is a valuable one and pushes me to re-examine the need for geographical subdivisions except where regional comparisons serve a specific purpose. Where lists are concerned, I usually have some mix of political, educational, sporting, and scientific agendas being entertained. A heck of a mix. Let's keep talking. Bob    RE: Regional lists   Paul Jost   May 04, 2006 08:20 PDT  Are we better off following established ranges of USDA hardiness zones? Paul RE: Regional lists   Darian Copiz   May 04, 2006 08:34 PDT  I would propose using the NatureServe ecological systems: http://www.natureserve.org/publications/usEcologicalsystems.jsp "Ecological systems represent recurring groups of biological communities that are found in similar physical environments and are influenced by similar dynamic ecological processes, such as fire or flooding" Darian Re: Regional lists   Edward Frank   May 04, 2006 16:50 PDT  Darian, That is a neat article. I have skimmed over the text and will print it out for a more detailed read. It could be used for our purposes. I am wondering if this ecosystem has recieved much acceptance among the general scientific community? Do you know if it has recieved favorable comment, been ignored, or been trashed? Was it published in a recognized Journal? Lee, Don, Don, Paul, Tom, Dale, Bob, Jess, and Will - any thoughts or comments? The report itself can be downloaded from the link listed below. it is an 83 page pdf document, 4.5 MB in size. Ed Frank Re: Regional lists   Don Bertolette   May 04, 2006 20:51 PDT  Ed- Then National Park system uses it... -Don Re: Regional lists   Lee Frelich   May 05, 2006 08:04 PDT  Ed: The Nature Serve (formerly part of TNC) plant community classification program is generally being used by most states and some federal agencies, and is recognized as the 'official' one by IAVS (international Association of Vegetation Science), and Ecological Society of America, Vegetation section. Parts of it have been published in peer reviewed journals. I helped work on it in an early phase about 10 years ago. Lee   Home