27, 2006 11:33 PDT
On a more general theme, for comparably sized areas, the
sites lead the northeastern sites by about 20 points. From the
now possess, that appears to be a fairly stable differential.
ever increasingly wide range of species, the differential will
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.
would be arbitrary, but 40 sounds about right to me, even though
doesn't match Pennsylvania's southern boundary? Anyone care to
the dividing line for ENTS purposes?
Robert T. Leverett
Cofounder, Eastern Native Tree Society
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
I would say that if the dimensions you recorded for that pine
demonstrate its potential within that geographical area, then
is extremely valuable and it should be included in a regional
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,
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
Again all of the forest types intermingle, but the political
cited seem to match reasonably well to the three zones I
the boundaries are variable nortth and south with intermingling,
boundary that matches fairly well is as good as a lattitude
doesn't match any better. There are also some practi cal and
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
above, Appalachian Mountains, Western Plateau regions,
and Southern coastal plain.
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
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?
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.
looked at a map depicting the major forest types in eastern
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
southern and included most of the northern pine-oak, most of the
beech-maple, much of the oak-hickory, and some mixed Appalachian
The Southern Zone included almost all of the Southern hardwood,
chunk of the Oak-Hickory, Mixed Appalachian, and Southern Mixed
This seemed a reasonable compromise to delineate the zones. If
zones were to be used I would go with southern border of PA,
Indiana to be the demarcation line.
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
skews what otherwise might me a clearer picture when just
latitude. In an aggregate sort of way, species distribution maps
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
serve a specific purpose. Where lists are concerned, I usually
mix of political, educational, sporting, and scientific agendas
entertained. A heck of a mix. Let's keep talking.
04, 2006 08:20 PDT
Are we better off following established ranges of USDA hardiness
04, 2006 08:34 PDT
I would propose using the NatureServe ecological systems:
"Ecological systems represent recurring groups of
that are found in similar physical environments and are
similar dynamic ecological processes, such as fire or
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
wondering if this ecosystem has recieved much acceptance among
scientific community? Do you know if it has recieved favorable
been ignored, or been trashed? Was it published in a recognized
Lee, Don, Don, Paul, Tom, Dale, Bob, Jess, and Will - any
The report itself can be downloaded from the link listed below.
it is an 83
page pdf document, 4.5 MB in size.
04, 2006 20:51 PDT
Then National Park system uses it...
05, 2006 08:04 PDT
The Nature Serve (formerly part of TNC) plant community
program is generally being used by most states and some federal
and is recognized as the 'official' one by IAVS (international
of Vegetation Science), and Ecological Society of America,
section. Parts of it have been published in peer reviewed
helped work on it in an early phase about 10 years ago.