RE: TO ALL ENTS!   Robert Leverett
  Sep 07, 2004 10:09 PDT 


... On a different subject, how many distinct sites can you think of
that have white pines that reach the Thoreau threshold? I've lost count
of the southern locations and the concentration of 150s at those sites.
It would be useful to at least have estimates of the number of 150s at
each listed site, even if we have classes of 200 and above as the most
numerous.  Maybe classes like the following would work:

Lower Bound                    Upper Bound
    1                                          1
    2                                           5
    6                                          10
   11                                          25
   26                                          50
   51                                         100
  101                                         200
  201                                  unlimited


RE: TO ALL ENTS!   Edward Frank
  Sep 08, 2004 20:13 PDT 


The difficulty with your question is figuring out what is defined as a
site. Is the Great Smoky Mountains National Park one site or many? If it
is a series of distinct sites, then virtually every watershed described is
a 150 site. Cook Forest is generally considered 1 site, but there are
several distinct old growth areas at Cook Forest separated by younger
second growth trees. Would an isolated tree in a field that reached 150
feet tall (not likely, but hypothetically) be considered a site? 

Ed Frank
  Sep 09, 2004 04:14 PDT 
    Colby, Will, and I have long struggled with the site definition problem. It rears its head with 150s, old growth, many things. As is clear from our loose usage of the term, a site can be any of those things you mentioned. MTSF has perhaps 6 geographically separate stands of pines with 150s. In bigger picture statistics, I lump them all as one site; i.e. MTSF. Political considerations, geographical features, convenience of access, etc. all influence what we whimsically call a site. About all we can do is to provide descriptions of areas we label as sites. In cases where there is a compact region delineated by clear boundaries and no adjacent areas with similar compositions, site becomes clear to everyone. Beyond those situations, we each define our sites as we see fit. Dale might break Cook Forest into subsites based on convenient boundaries, the network of trails, stand histories, etc. I'm sure that we'd all honor his boundaries. 

Bob, S.C.

RE: TO ALL ENTS!   Lee E. Frelich
  Sep 09, 2004 07:52 PDT 


The hierarchical organization I use for studies usually goes like this from
small to large spatial scale:


Neighborhood, a grove of adjacent trees within a stand.

Stand, an area of one forest type with fairly uniform soils and disturbance
history within a site.

Site, a cluster of similar stands (i.e. pine stands on moraines, lowland
stands along a river, dwarf forests along a ridgetop).

Study area, a cluster of sites that may be very heterogeneous and have
several forest types, usually defined by political boundaries (i.e. Great
Smoky Mountains, MTSF, Porcupine Mountains).

Region, a large are defined by political or biogeographical boundaries
(i.e. the Southern Appalachians, New England, deciduous forest biome).

Note that this scheme for practical application during field studies is
different than the biological hierarchy:


And different than the hierarchy used in the national ecological
classification system (which is fully nested in a spatial sense):

ELTP, Ecological land type phase, basically equivalent to a stand
ELT, Ecological land type
LTA, Landtype Association


Site delineation    Edward Frank
   Nov 11, 2004 19:46 PST 


I have been thinking about how individual sites should be delineated. On
reconsideration, I agree with Bob Leverett's initial feeling that the
delineation of a particular site should be left to the individual
describing it. I would like to see the limits of a site be explained or
delineated, but conditions from area to area are so variable that a
one-size-fits-all strategy for site delineation would be counterproductive
at this moment.

I can give an example of classification problems that still plague geology
today. Coarse grained igneous rocks (volcanic rocks) form a continuum from
one chemistry containing quartz and potassium feldspar through orthoclase
feldspar and hornblende, to olivine and pyroxene. Examples mixtures of
these and all of the in-between mineral assemblages can be found. So early
on in geology they divided the coarse grained rocks into three broad
groups: Granite representing one end of the spectrum, light in color with
quartz and Potassium feldspar. Diorite - a middle ground of half dark and
half light minerals, generally calcium feldspar and hornblende. Gabbro -
dark igneous rock with pyroxene, hornblende, and olivine. Minor amounts of
other minerals are also found in each of these assemblages. This makes
sense, light, medium, and dark. However with a hundred and fifty years of
research (that is how young serious geology is) we have found that plots of
the most common chemistries actually fall into four general clusters.
Many of the of the lighter colored, coarse grained rocks are not
really granite but are granodiorite. On the standard classification scheme
taught to everyone, this common of the light coarse grained igneous
rock falls half within the granite category, and half within the diorite
category. The classification is so ingrained it is hard to change, and it
doesn't match real world clusters of rock chemistries.

So it would be best to see what is out there that naturally demarcate a
particular site, look at how sites in general tend to be demarcated, before
trying to force an arbitrary site boundary classification protocol on the
real world situation.

I can see several factors that might in varying circumstances be used to
delineate boundaries of a site: Between areas that have been timbered and
those that have not (these may correspond in some cases to political
boundaries), The amount of water at a site, (in the extremes arid through
swampy), The exposure at the site (open versus sheltered), Boundary
corresponding to a disturbance boundary, Hilltop hillside, ravine, or flat
valley. I am interested in seeing what else is found in the real world

Ed Frank