Regional Tree Divisions   Robert Leverett
  Apr 27, 2006 11:33 PDT 

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?


Robert T. Leverett
Cofounder, Eastern Native Tree Society
Regional Tree Divisions   Robert Leverett
  Apr 28, 2006 05:06 PDT 


   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


Re: Regional Tree Divisions   Edward Frank
  Apr 28, 2006 16:51 PDT 


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

A Mid-transition zone with mixed forest types: Including PA, OH IN, IL, MO,

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 


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.



   Good food for though. Lee, what do you think about Ed's three zones?

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

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

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.

Regional lists   Robert Leverett
  May 04, 2006 04:15 PDT 


   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.

RE: Regional lists   Paul Jost
  May 04, 2006 08:20 PDT 

Are we better off following established ranges of USDA hardiness zones?

RE: Regional lists   Darian Copiz
  May 04, 2006 08:34 PDT 

I would propose using the NatureServe ecological systems:

"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"

Re: Regional lists   Edward Frank
  May 04, 2006 16:50 PDT 


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

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 


Then National Park system uses it...

Re: Regional lists   Lee Frelich
  May 05, 2006 08:04 PDT 


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.