Rethinking application of the Rucker Index   Robert Leverett
  Nov 03, 2004 06:00 PST 
ENTS:

    Will Blozan's and John Eichholz'a recent confirmations of more
exceptional trees in the Trout Brook region of Mohawk Trail State Forest
suggests the need to begin the process of breaking down our large,
mainly political units, such as national parks, state forests,
conservation properties etc. into sub-sites that are delineated more
through ecologically derived criteria than convenient political ones. We
all knew this was coming, but I do believe that the time has arrived.

   The Trout Brook cove in MTSF includes about 125 acres of prime
growing habitat that includes similar geology, climate etc. I think Lee
Frelich would describe much of the forest type in Trout Brook as mature,
even-aged, grading into old growth on the steep upper slopes. In
addition most of the forest on the lower slopes has a fairly common
human disturbance history. It seems reasonable that Trout Brook should
have its own Rucker index.

    One undeniable fact is that the Trout Brook area is very rich for
growing trees. The Rucker index for a 125-acre Trout Brook sub-site now
stands at 127.5 and can likely go just a little higher. In 20 or 30
years, the index will climb to between 129 and 130, barring loss of
species.

    On the north side of route #2, the Todd-Clark ridge gives rise to a
200-acre swath of forest that has a Rucker index of around 132. The area
has swaths of older forest and probably represents climax vegetative
development in terms of tree height growth for any area in
Massachusetts. The area has the same geology and climate. It too
logically should have its own Rucker index.

    As we expand the geographical area, naturally we increase the Rucker
index, but it is interesting to follow how well the hot spots like Trout
Brook and Clark ridge fair, i.e. to assess their contributions. With the
latest numbers cranked in, MTSF's Rucker index still stands at 134.5,
courtesy of this past weekends measurement of the Jake tree. So, going
from 200 acres to 6770 yields an increase of only 2.5 points with
respect to the Clark ridge site. Darned impressive.

    Expanding to include significantly larger, more diverse areas that
would eliminate the dominance of a local geology, topography, climate,
and forest history and then telescoping down to small regions to
investigate the patterns will be grist for the cold days of winter spent
indoors at my computer. However, this I can already see. A few small,
contiguous, compact areas will continue to account for most of the tall
tree contributions. I would have once thought that the more searching I
did the more spread out the locations of each of the champions would be.
I never actually expected that 2 or 3 compact areas would continue to
contribute so much to the Rucker index calculations.

   It will take a lot more roaming around and sampling to adequately
validate this pattern, but I can't think of anything I'd rather be
doing. So many trees, so little time ......

Bob
          

Robert T. Leverett
Cofounder, Eastern Native Tree Society
Re: Rethinking application of the Rucker Index   Edward Frank
  Nov 03, 2004 18:14 PST 

Bob,

We have discussed various aspects of this in the past. Last fall as a part
of the discussion regarding the workings of the rucker index itself. I
would like to review what has been said so far:

To Colby Rucker I posed a question about how the indexes could be artificially
inflated by including larger areas, the equivalent of gerrymandering in
designing political precincts.

Colby (July 27, 2003) wrote: “Habitat is much more
important than acreage...Yes, we can increase index ratings by
incorporating more territory. By lumping a lot of Jess Riddle's sites
for Station Mountain or the Andrew Pickens Ranger District, the numbers
went up, but it showed that the Great Smoky MNP wasn't so unique.
Sometimes smaller sites make a good showing, as at Ice Glen (ca. 40 a.),
Belt Woods (43 a.) or Chase Creek (ca. 150 a.). I don't think there'd
be any point segregating sites according to acreage at this point. We
don't have much info on privately-owned sites; Chase Creek is the
primary example.” I believe as we collect more data perhaps some
evaluation may need to be made of this factor. But at the moment we
simply need to rely on the people making the evaluations to fairly
delineate the boundaries of the study area."

In September 2004 I wrote: "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?" 

Bob (Leverett) replied: "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." 

Lee Frelich posted Sep 09, 2004 about what defines a site (an excerpt from
his longer description is as follows: "The hierarchical organization I use
for studies usually goes like this from small to large spatial scale:

Tree

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)."


What do I think about the issue at this time?
It is simply a fact that the larger the area incorporated, the greater the
Rucker index you will be able to calculate. That said, it is also true as
you have pointed out above, often a large proportion of the big trees for a
large site will be concentrated within a small area. It makes sense that
the sites should be defined on an ecological basis. That would give the
best scientific basis for using the data collected. But still you have the
problem of defining what is a particular ecological boundary. Could this
be applied fairly over a large area with diverse geologic, climatologic,
and biotic regimes by many different people? I don't think it can be. It
would be better to have ecologic boundaries, but I don't see how consistent
boundaries for all of the sites in eastern US could be defined. It would
be workable for you to consistently define boundaries within an area you
worked, say MTSF, but a different person in the GSMNP would have boundaries
defined differently. Would these boundaries be comparable in any useful
way?

I don't like the political boundaries used now, so perhaps ecological
definitions could be used for select sites for which we have a large amount of 
data. A detailed description would be needed for the criteria used to define the
boundaries of the sites. I think it would be worthwhile if some sort of
size was listed for each site that was described - in acres hectares, square
miles, or sq kilometers for general information purposes. But these may be
hard to determine and I am not sure it would be practical. In some cases a
political boundary between a primary forest and a second growth timbered
stand regime might be the best definition. I do like the hierarchy Lee
listed above for defining a stand and a site.

I am interested to see what you come up with in this regard.

Ed Frank
Re: Rethinking application of the Rucker Index   John Eichholz
  Nov 03, 2004 19:36 PST 

Ed,

That is quite a nice summary of what has come before. One point I would
add from a practical measure: When a rich, high growth site is
encountered, such as one of the several coves facing north towards route
2 in MTSF, there is a higher potential for most of the trees in it. Move
a few hundred feet in any direction and often the heights fall off
dramatically. The Rucker index measures actual attained height, and as
such has a valid definition for any bounded area. 

I guess what we are
grasping at here is maximum site potential, which would have to be
defined quite locally to be valid. A study of tree heights in a
statistically valid set of random plots across the face of any of these
areas would likely show a strong correlation between features we are all
familiar with and tree heights. So, the Rucker index of a site is a
reflection of the maxima of these samples, while a site potential index
would be an average of them. Honing in on or limiting to a high growth
zone would likely increase (maximize) the site potential index, thereby
demonstrating its local nature.

John
Re: Rethinking application of the Rucker Index   Edward Frank
  Nov 03, 2004 21:46 PST 

John, Bob, Will, and other ENTS

One thing that has always bothered me about the measurements used in the
Rucker index. Everyone always talk about the tallest of the trees we find
as representing the growth potential for that species in a particular area.
To what degree does this actually demonstrate the production of trees in
that area?

The tallest trees may be statistical outliers that represent the freaks of
the species, and not representative of the potential for that species as a
whole. If you measured Manute Bol, 7' 7" former NBA player, would he
represent the growth potential for humans in the area? Yes and no. He
obviously grew that tall so in a literal sense he represents the maximum
growth potential for a given group of humans. But given 1000 other people
with exactly the same diet, and environment, would all of them grow to that
height? No, they would not.

So what you are in effect measuring is the broadness of the upper end of
the statistical bell curve. These particular trees grow to that height, so
the potential for the species to grow that high in that area is
demonstrated, but... does this number represent how tall most trees of the
same species will grow in that area? No, I don't think so. Everything
else being equal, most trees would not grow to that height, most would be
shorter.

It has been suggested that some of the Eastern White Pine tree stands at
Cook Forest are 300 years or so old. At that age are they continuing to
grow taller, and how fast? The Longfellow Pine is 182 feet tall. Will the
other trees given time grow that tall or stop growing upward at some lower
height?

Say if you had two species of trees with the same maximum height found on
your measuring trip. Both would have the same height potential as shown by
your measurements. But if one distribution was broader or skewed to the
upper end, then the actual numeric average of the height reached over time
for all trees of each species may be drastically different.

We are looking at each site essentially as a snapshot in time. We are
measuring the tallest trees of each species on that site. How well do these
tallest trees we are measuring, these statistical upper outliers, represent
the actual growth that would take place for the majority of that species at
that site?

I may not have expresses myself clearly, but I don't know how else to
explain my quandary.

Ed Frank
More on Rucker indices   Robert Leverett
  Nov 04, 2004 07:06 PST 

Ed:
    Concerns expressed so far about use of Rucker indices are legitimate
and it is good that we periodically explore the role and value of the
Rucker index as we tend to apply it. Renewed discussions and your
research of what each of us has said in the past is a way that we can
keep ourselves from straying too far from the straight and narrow.
    An important point to make to the membership at large is that
there's more to what the few of us are doing with Rucker indices than
shows on the surface in these e-mail posts. What accompanies the use of
the indices by those of us who regularly employ them is usually unstated
in our ENTS e-mails. Tree age, or at least age class, is a key factor
that we don't always report on in our e-mail posts, but all of us employ
age constantly. Then there are the environmental factors that we
sometimes discuss, but don't usually report in any systematic way. I
come closest with latitude, longitude, and altitude. There are also the
height to diameter ratios that we compute, but only occasionally report,
such as when an unusually high ratio is encountered. For my purpose, I
look at the ratios in my database constantly. Lee has a method for
employing H/D ratios that allows for site to site comparisons as a
substitute for the site index approach of forestry that requires knowing
tree-stand age.

    I would acknowledge that what we do on the ENTS list is often the
sport end of the reporting, i.e. Will, Dale, Jess, Tom, John, John, me,
etc. doing the fun thing, but there's a constant behind the scenes push
to understand what the numbers mean. The deep science is being handled
by Lee Frelich.

     As is apparent to those who have been on the list for a long time
(provided they read the e-mails), I periodically send out a
communication to refocus discussions on indices and our use of them -
knowing full well the daunting challenges of us agreeing on a fine-tuned
system of application. To our membership at large, I would say that
there is a behind-the-scenes order to what otherwise appears to be
little more than a sporting endeavor. We are moving toward the creation
of a system of "ecological compartments" in MTSF. We have a number of
recognizable and definable habitats and forest associations/types in
Mohawk and we can draw fairly accurate boundaries to reflect them. We
can also divide them into high and low growth regions. Getting all the
measurements and observations into a database is a lot of work though. I
suspect that each of the Tree Amigos carries a mental map of MTSF and
the different types of terrain and habitats within Mohawk. I most
definitely do. My brain cell maps tell me much more about what to expect
in tree growth than I presently communicate with words in my e-mail
postings. I expect that we still all carry our best computers in our
heads.

    For instance, when in MTSF, I clearly recognize the irregular
boundaries of the old growth, of even-aged stands of trees of human
origin, of bands of high growth, of low growth, the seeps, the dry
zones, of the different forest classes. Ed, as you specifically saw, I
don't understand the bed rock in Mohawk and that is a deficiency I want
to eventually overcome. But through the twists and turns, I continue to
see many applications for indexing that can communication the tree
growth implications for various ecological classifications that we might
devise, but this having been siad, the time to do all the research
remains daunting. We peck away at it, picking up a few numbers here and
there and reporting on our finds, often in a sporting or promotional
way. That part of it is sheer fun, but the ecological picture is always
behind the scenes in our minds and kept in context with dozens of other
sites.

     For instance, Mohawk is really a window to the upper Deerfield
River watershed in Massachusetts. Monroe State Forest is another. John
Eichholz's Mount Peak site is a third. As we accumulate site indices,
the productivity of the Deerfield River corridor can be compared and
contrasted to both adjacent and more distant watersheds. Even with our
catch as catch can approach, with enough data points, present and
potentail growth pictures will eventually emerge for the specified
watershed at the macro view and of course at the micro site level - and
that is what we are really seeking to understand - species potential.
    What I've just said does not mean that I don't value the site
indexing except for scientific purposes. While political boundaries
don't mean anything in science, they are necessary in our presentations
to state officials and the general public, because for the management of
public lands in Massachusetts, state forest, park, and reservation
boundaries are of critical importance. Nothing revealing there. So, does
this mean that the 134.5 Rucker index as applied to the political unit
of MTSF has significance beyond sport and some science? Yes, without
question. Science, politics, sport, and promotion all play important
roles. The role exist for Cook Forest, PA, Hartwick Pines, MI, the
GSMNP, and so on.

      The deliciously satisfying part of all this is that we in ENTS are
uniquely positioned to hit all the bases; science, sports, politics, and
promotion - and have fun doing each, something that cannot always be
said when one is acting solely within the boundaries of one's
profession.

Bob


Robert T. Leverett
Cofounder, Eastern Native Tree Society
Sites   Darian Copiz
  Nov 04, 2004 10:35 PST 

Just some thoughts. For a site to offer the best empirical data, I
think as many variables as possible should be eliminated. I would
define a site as the same contiguous or nearly contiguous soil, slope,
and aspect. That would mean that a ravine cutting through a flatter
upland area would not be part of the upland area site. Not sure of the
practicalities of this, but it seems to make sense to me. Maybe all the
huge hemlocks grow only in the ravine. If the site in question is
primarily the upland portion, would including the ravine tell us very
much about the area as a whole?
RE: Sites   Robert Leverett
  Nov 04, 2004 11:02 PST 

Darian:

   And indeed that is usually the case. Ravines have their own special
micro-topography as do concave boulder fields with abundant seepages.

    Some of us started the process of identifying the growth varibales
by trying to identify just the most essential ones. Continuous access to
moisture, soil chemistry and depth, aspect, protection from high winds
and landslides, and annual degree-days were the principal ones we
commonly entertained. The practical problem is that within even small
areas of mountainous regions, we often find a variety of high and low
growth microsites.

     Benches at the base of rock ledges and the center of concave
boulder fields with medium-sized boulders have produced surprises. The
toe slopes of ridges can be phenomenal growing machines. Essentially if
a microsite offers sufficient water, soil, and protection, the
probability of rapid tree growth skyrockets.

   We're going to be at the job of quantifying the environmental
variables for a long time. However, at this juncture, I'm reluctant to
adopt any protocal that is labor intensive, just because my time is so
limited. So the search for surrogates goes on.

Bob
Re: Greenbrier & Cosby (Smokies)   dbhg-@comcast.net
  Nov 06, 2004 04:47 PST 
Jess:

    As usual, a wing ding report. We've come to expect stellar performances from you in the fine detail you provide us. Your trip reports set the standard.

    In terms of the areas that you regularly visit, what are your thoughts on the division sites and sub-sites for the purpose of applying Rucker height, diameter, and height/diameter ratios? I ask this question, not because I can't infer from the detail you provide how you are "seeing" the sites, but because I've been thinking about developing the concept of breaking down the politically-defined sites in Massachusetts into sub-sites, where a variety of terrain types are represented. However, I don't want to find myself subconsciously tree-mandering the sites to get a high index, nor getting excessively detailed trying to thread the needle in terms of defing a site around relatively constant characteristics.

   In thinking about minimum sub-site size, where the area is vast, such as the Great Smokies, a sub-site must take on more of the role of a sample, with aneed for a lot of samples see the big picture. The area is vast and the discoveries never ending. So I'm unsure if the same approach can be taken as in the case of the Massachusetts sites that we typically cover.

    For instance, with the Ice Glen site, the area we usually include covers almost exactly 25 acres. Those acres have produced an index of 126.2. Expanding the acreage to 50 would likely not raise the Rucker index so much as a 1/10 of a point. So we have likely captured a regional maximum. It is possible we could add 0.3 - 0.5 points by expanding into the hundreds of acres or even thousands. But basically, we're at the zenith of the region. Call us lucky, I guess.

    With MTSF, we have a much more complicated situation. The whole of Mohawk seems to represent the maximum for a very large region, but to get that maximum, we combine more types and variations of terrain. Lots to think about.
Bob
Re: Rethinking application of the Rucker Index   John Eichholz
  Nov 08, 2004 20:20 PST 

Ed:

Good points.

I think (time will tell) that working within a high growth area we will
be able to show that the height of canopy trees of a single species
follows a bell curve. The modal (most frequent) height will say
something useful about the growth potential of the area, epecially if
combined with information about age since disturbance and stem
diameters. But, usually it is too much work for us to measure enough to
determine the modal height. The shape of the curve is ultimately
unknown, but there are some trends.

I think a few iterations of the Rucker index will be enough to get
beyond the outliers for small sites. With the small number of trees in
some of these high growth areas anything more than one or two outliers
starts to seem normal. Also, the maximum heights, represented by the
first iteration, are real trees. Unless they are relics or somehow of a
different history than the rest of the site, they do reflect the rest of
the trees nearby. They have similar genetics and growing conditions at
least. Pondering the exceptions gives a deeper meaning to the sport of
searching.

This may break down once an area goes beyond the stem exclusion phase to
the gap replacement (?) phase. Succession will also have an effect. A
second growth stand has more predictable characteristics than an old
growth stand. The frequency of catastrophic climatic events also limits
growth. In the end there may be more questions than answers. But, if
we look for answers we might find them.

John
RE: Rethinking application of the Rucker Index   Robert Leverett
  Nov 09, 2004 11:35 PST 

John:

   I think you are on the money. Those of us who apply the Rucker index
are not just blindly looking for the tallest tree of each of the 10
tallest species. We're measuring many trees and getting a sense of what
a single iteration of the Rucker index tells us. My wintertime challenge
is to write a Visual Basic program that computes an nth order Rucker
index for a site. Doing it manually is too much work. I have a program
that computes a 1st order index for a site. I just have to figure out
how to replicate the process. But before spending the time developing
the program, I'll probably update Mohawk out to ten iterations. We've
added lots of tall trees.

Bob
Re: Greenbrier & Cosby (Smokies)   Jess Riddle
  Nov 10, 2004 09:21 PST 

In general, I see little reason to breaking down the SC sites into smaller
units. That position results from the fact that multiple interfaces
coincide to naturally delineate most of the sites. .. Full text of reply at:

South Carolina Site Divisions
Questions for Jess and Will    Robert Leverett
   Nov 11, 2004 05:40 PST 


Jess:

    You've given us useful insights into how you see the landscape-scale
areas and specific sites you are studying.

    In MTSF, bedrock geology, depth of the humus layer, aspect, slope
angle, a loose composite terrain index, water availability during the
growing season, degree-days, protection from high winds, frequency of
ice storms, and forest history leading to the current composition and
age structure have become the variables we discuss at the micro-site
level. Measuring them all is a different issue, but at this point, we
try to qualitatively assess them. As the physical area expands to
include more variation in the above factors, our attention turns more
toward identifying area-wide ceilings and general trends. For instance,
as an example of a ceiling, a Rucker index of just under 135 appears to
be the absolute maximum for any contiguous area of around 2,500 acres in
MA. What is more interesting is that the 135 ceiling can be applied to
much larger contiguous areas. This was not expected when we began to
compute the Rucker indices and build our sites studied list.

   For instance, the Rucker index for all of Massachusetts presently
stands at 137.65. For the single property of MTSF, the index is 134.46.
That's only 3.19 points or a 2.4% increase to go from one small property
in the Berkshires to the entire state - a state that includes several
rich river valleys. Even with future discoveries, that are bound to
come, it is doubtful that the percentage increase will go beyond 2.9% or
3.0%. I won't go into the reasons for projecting this ceiling, but there
is a wealth of supporting evidence.

    It will be interesting to see if the surrounding states have
comparable single site dominances that hold as ENTS continues searching
and documenting the best tall tree sites. At present Cook Forest State
Park's 135.58 compares to 144.29 for PA as a whole. Adding 8.71 points
to Cook to reach the State index amounts to an increase of 6.4% over
Cook Forest's index. I would expect that percentage to rise even higher
as Dale covers more and more territory. I could see PA's state Rucker
index going as high as 146. That would amount to a 7.7% increase over
Cook. That's PA. What about NY?

    Based on what we see, it is likely that the Zoar index will stay
between 93% to 95% of NY's index. However, our data for NY is extremely
limited. The 5% to 7% projection is going out on the proverbial limb,
but based on the regional data that we have collected for the
represented species, the projection appears quite realistic. Are there
other single site dominances?

    I'm willing to bet that the Claremont site in NH is within 4% to 5%
of the entire State. Unfortunately, we don't presently have enough sites
to justify prediction of single site dominance for CT, RI, VT, ME, or NJ
- the remainder of the Northeast.

    The central question facing us now is why are Zoar Valley, Cook
Forest, and MTSF so dominant in their respective states? Is it a lack of
state coverage by ENTS? In the case of Massachusetts, the answer is
emphatically no. That will likely also soon be the answer for PA. NY
will require much more time. But, suppose we scour NY from corner to
corner measuring and documenting and Zoar Valley holds to within 6% to
7% of the entire state. What would we make of such an extraordinary
statistic, given the size and forest diversity of the empire state?
Similarly, suppose Cook holds onto its margin relative to the rest of
the keystone state. Anomalies? I don't know.

   Moving southward, let's take the NC part of the Smokies and compare
it to all of NC. Will Blozan is the expert, but I'd be surprised if the
story is much different. I'll bet the Smokies rides to with 4% to 6% of
the NC, as a whole - maybe within 2% to 3%. Will, what do you say?

    Now to South Carolina? Jess, what is SC's current Rucker index? How
does it compare to: (1) your best mounatin property, (2) Congaree?

Bob


Robert T. Leverett
Cofounder, Eastern Native Tree Society
Re: Questions for Jess and Will   Jess Riddle
  Nov 15, 2004 06:27 PST 

The Rucker Indices for the tallest piedmont site in SC, the tallest
mountain site in SC, and the state of South Carolina are followed by a
discussion of that Rucker Indices of superlative sites versus the Rucker
Indices of their host states.
Species listed by first two letters of genus and first two letters of
specific epithet.

Congaree Swamp NP

PITA 167.2 Pinus taeda = loblolly pine
LIST 157.1 Liquidambar styraciflua = sweetgum
QUPA 154.0 Quercus pagoda = cherrybark oak
PLOC 144.0 Platanus occidentalis = sycamore
TADI 141.0 Taxodium distichum = baldcypress
ULAM 135.0 Ulmus americana = American elm
QUMI 132.8 Quercus michauxii = swamp chestnut oak
PODE 131.0 Populus deltoides = eastern cottonwood
QULY 131.0 Quercus lyrata = overcup oak
DIVI 126.9 Diospyrus virginiana = persimmon

RI 142.00

Central Brevard Fault Zone

LITU 170.2 Tamassee Knob Lirodendron tulipifera = tuliptree
CAGL 168.2 Lee Branch Carya glabra = pignut hickory
CACO 154.2 Station Cove Carya cordiformis = bitternut hickory
QURU 150.0 Lee Branch Quercus rubra = northern red oak
QUMO 143.9 Tamassee Knob Quercus montana (Q. prinus) = chestnut oak
ROPS 143.4 Tamassee Knob Robinia pseudoacacia = black locust
QUAL 141.8 Station Cove Quercus alba = white oak
LIST 141.4 Tamassee Knob Liquidambar styraciflua = sweetgum
ULRU 141.3 Station Cove Ulmus rubra = slippery elm
PIEC 139.9 Tamassee Knob Pinus echinata = shortleaf pine

RI 149.43


South Carolina

LITU 170.2 Tamassee Knob Lirodendron tulipifera = tuliptree
PIST 168.9 Walhalla Fish Hatchery (E. Fork) Pinus strobus = estern white
pine
TSCA 168.9 East Fork Chattooga River Tsuga canadenis = eastern hemlock
CAGL 168.2 Lee Branch Carya glabra = pignut hickory
PITA 167.2 Congaree Swamp NP Pinus taeda = loblolly pine
LIST 157.1 Congaree Swamp NP Liquidambar styraciflua = sweetgum
CACO 154.2 Station Cove Carya cordiformis = bitternut hickory
QUPA 154.0 Congaree Swamp NP Quercus pagoda = cherrybark oak
FRAM 153.4 Wadakoe Mountain Fraxinus americana = white ash
QURU 152.9 Whitewater River Quercus rubra = northern red oak

RI 161.50

 State vs Congaree. (161.5/142.00-1) x 100 = 13.7%
State vs Brevard Belt (161.5/149.43-1) x 100 = 8.1%

Looking at the circumstances necessary for a significant increase in a
Rucker Index, the dominance of MTSF in Massachusetts and the greater
variety of contributing sites in SC do not seem all that surprising. A
state could have a much higher RI than the best site in the state under
one of two conditions or their combination: much taller individuals of
the same species as at the best site grow found elsewhere in the state; or
very tall species that do not grow at the best site grow elsewhere in the
state.

How likely is it that top ten species at the best site would all approach
their regional maxima? Several months ago, Colby Rucker posted a well
thought out argument for the best site for a species being the one that
the species is best adapted to, where it has the greatest competitive
advantage, and that that would usually not coincide with the area of
greatest resource ability. That hypothesis could be interpreted as
implying that height records would require different sites and thus be
quite spread out spatial; however, sites as trees actually use them are
much smaller than any of the areas we have defined them, and disturbances
could shift a specific location from being ideal for one species to being
nearly ideal for another species. Additionally, even our relatively
homogeneous sites contain small but significant variations in moisture
availability, aspect, and soil composition. Consequently, slight
gradients in environmental conditions, microsites, and disturbance
patchiness on a background of high water and soil nutrients, physical
requirements of great height growth of all species, could result in nearly
ideal habitat for several species occurring in a small area that appears
relatively homogeneous.

How likely is it that all of the tallest species in a state would all
occur at one location? The distribution of physiographic provinces within
a state and latitude of the state largely answer that question. Most rich
site support all or nearly all of the tall species in that physiographic
province. However, in other physiographic provinces, the same species may
have vastly different growth potential. For instance, silverbell grows in
the understory along many southeastern piedmont streams, but becomes an
overstory species in the southern Appalachians. Also, in the northeast,
nearly all of the tall species grow well in the mountains; the coastal
plain of the region has few extremely tall species. Conversely, in the
south, a host of bottomland species reach great size in the piedmont and
coastal plain, but cannot survive compete in the mountains.

Going back to the individual sites, MTSF provides excellent growing
conditions for almost all of the mountain species in Massachusetts. In
other regions of the state, sycamore, tuliptree, and cottonwood are the
only additional tall species I know of, and of those I think sycamore is
the only one that is known to challenge the mountain species in height in
that region (have I been paying close enough attention to your e-mails
Bob?). Hence, small improvements in mountain species at other sites and
sycamore are the only avenues left for Massachusetts to increase the
state's Rucker Index over MTSF.

The same general argument applies to Cook SF, but the argument is not
quite as strong. A few broadleaf mountain species, tuliptree in
particular, do not approach their regional maximums in the park, and
lowland species like sycamore and cottonwood reach more impressive heights.
In South Carolina, the tallest species different regions of the state
ensure some of the tallest species of the state stay well separated, so no
one site can achieve the dominance of some of the northeastern sites.
Compounding that divide is the fact that the best conifer and broadleaf
sites in the mountains do not coincide. In spite of those considerations,
the central section of the Brevard Belt still comes within 10% of the
state Rucker Index. That situation highlights the fact that the
second-tier tall species are not that much shorter than the tallest group
of species. 15 feet may seem like a great height difference, but that
length is still less than 10% of the height of the tallest species.

North Carolina has great tree diversity and distinct physiographic
provinces, so the dominance of the Smokies appears to contradict the
pattern established in looking at the other sites. I attribute part of
the dominance simply to the fact that the Smokies are a special area.
Lack of disturbance, and lack of continued disturbance, climate, geology,
and the resultant high diversity all work in favor of the site. The other
part of the smokies dominance is probably an artificial artifact of how we
have set up the situation. The NC side of the park contains several
distinct high growth areas that are separated by areas of shorter forest
with different growing conditions, and the high growth regions are spatial
separated by a few miles. If not for the park boundary, we would probably
see the area as having several distinct superlative sites rather than one
large, incomparable site. The other human factor is the paucity of data
we have form the NC piedmont and costal plain. Will Blozan has just
recently found one excellent piedmont site giving a specific example of
the regions potential. How tall can sweetgum, loblolly pine, cherrybark
oak, and shumard oak grow in the state's floodplains.

Zoar Valley's dominance in New York points to some holes in this theory
and the spectacular nature of the site. New York has several distinct
regions, yet Zoar Valley appears to include excellent habitat for all of
the tall hardwood species in the state. The lack of conifers makes the
sites dominance more impressive, but reinforces the fact that the second
tier of tall species really is not that much shorter than the tallest
group of species.

Enough half thought through rambling.
Jess Riddle
Jess and Bob Colloquy   Robert Leverett
  Nov 17, 2004 06:45 PST 

Jess:

   Good analysis and interesting points to ponder. I'll provide my
comments at appropriate spots below in a first Jess then Bob format.
Then maybe others will see merit to joining in.

Jess said:

Looking at the circumstances necessary for a significant increase in a
Rucker Index, the dominance of MTSF in Massachusetts
and the greater variety of contributing sites in SC do not seem all that
surprising. A state could have a much higher RI than the
best site in the state under one of two conditions or their combination:
much taller individuals of the same species as at the best site grow
found elsewhere in the state; or very tall species that do not grow at
the best site grow elsewhere in the state.

Bob's reply:

    The circumstance I would have expected for Massachusetts would have
been the combination. Three species that I would
have thought would have contributed more to the state's differential
over the single site is tuliptree, sycamore, cottonwood, and
maybe one of the hickories. I would also have expected a small
differential in the state's favor from black cherry and sugar maple.
All in all, I would have expected the state's index to be around 140
and the highest single site to be around 130 for a differential
of 10 instead of 3.19. I realize that 10 doesn't seem all that far
removed from 3 when the base is between 130 and 140, but when
the species are tracked over a large geographical region, amounts that
seem small to others can be conspicuous to us. So I'm not
arguing for large overall differences, just for more differences than
we are seeing.

Jess said:

How likely is it that top ten species at the best site would all
approach their regional maxima? Several months ago, Colby Rucker
posted a well thought out arguement for the best site for a species
being the one that the species is best adapted to, where it has
the greatest competitive advantage, and that that would usually not
coincide with the area of greatest resource ability. That
hypothesis could be interpreted as implying that height records would
require different sites and thus be quite spread out spatial;
however, sites as trees actually use them are much smaller than any of
the areas we have defined them, and disturbances could
shift a specific location from being ideal for one species to being
nearly ideal for another species. Additionally, even our relatively
homogeneous sites contain small but significant variations in moisture
availability, aspect, and soil composition. Consequently,
slight gradients in environmental conditions, microsites, and
disturbance patchiness on a background of high water and soil nutrients,
physical requirements of great height growth of all species, could
result in nearly ideal habitat for several species occurring in a small
area that appears relatively homogeneous.

Bob's reply:

True. The many microsite differences can create a far wider range of
growing habits than we might typically believe. This is
especially true in mountainous terrain that provides dramatic changes in
aspect, slope, bedrock geology, mositsure availability,
and protection. So this argues for a single site reaching closer to not
only the regional maximum, but the max for the entire state.

Jess said:

How likely is it that all of the tallest species in a state would all
occur at one location? The distribution of physiographic provinces
within a state and latitude of the state largely answer that question.
Most rich site support all or nearly all of the tall species in that
physiographic province. However, in other physiographic provinces, the
same species may have vastly different growth potential. For instance,
silverbell grows in the understory along many southeastern piedmont
streams, but becomes an overstory
species in the southern Appalachians. Also, in the northeast, nearly all
of the tall species grow well in the mountains; the coastal
plain of the region has few extremely tall species. Conversely, in the
south, a host of bottomland species reach great size in the
piedmont and coastal plain, but cannot survive compete in the mountains.

Bob's reply:

Yes, and for that reason, I wonder if further searching of the SC
lowlands will yield a couple species that will knock out a like
number of mountain contributors to widen the difference between state
and single site? Past comments of BVP suggest that he
believes the rich lowlands once grew the tallest trees.

Jess said:

Going back to the individual sites, MTSF provides excellent growing
conditions for almost all of the mountain species in
Massachusetts. In other regions of the state, sycamore, tuliptree, and
cottonwood are the only additional tall species I know
of, and of those I think sycamore is the only one that is known to
challenge the mountain species in height in that region
(have I been paying close enough attention to your e-mails Bob?). Hence,
small improvements in mountain species at other
sites and sycamore are the only avenues left for Massachusetts to
increase the state's Rucker Index over MTSF.

Bob's reply:

Yep, indeed you have been following the Massachusetts posts, Jess. But
tuliptree should do more than I've confirmed. Again,
the differential between the state and the state's premier site might,
for the arguments you've made, not be overwhelming, but it
should be more than we are observing. The state's second highest site is
Ice Glen. It's Rucker index stands at 126.2 as opposed
to Mohawk's 134.5. Mohawk exceeds Ice Glen The state index exceeds Ice
Glen by 11.45 and MTSF exceeds Ice Glen by 8.26.
There is only one other site in Massachusetts that exceeds 120 and I
suspect we could look indefinitely and find at most one or
possibly two more and the odds are that they would just break 120. The
degree of domination of the single site of MTSF is the
unanticipated part of the equation.

Jess said:

The same general argument applies to Cook SF, but the argument is not
quite as strong. A few broadleaf mountain species,
tuliptree in particular, do not approach their regional maximums in the
park, and lowland species like sycamore and cottonwood
reach more impressive heights.In South Carolina, the tallest species
different regions of the state ensure some of the tallest
species of the state stay well separated, so no one site can achieve the
dominance of some of the northeastern sites. Compounding
that divide is the fact that the best conifer and broadleaf sites in the
mountains do not coincide. In spite of those considerations,
the central section of the Brevard Belt still comes within 10% of the
state Rucker Index. That situation heighlights the fact that
the second-tier tall species are not that much shorter than the tallest
group of species. 15 feet may seem like a great height difference, but
that length is still less than 10% of the height of the tallest species.
North Carolina has great tree diversity and distinct physiographic
provinces, so the dominance of the Smokies appears to contradict the
pattern established in looking at the other
sites. I attribute part of the dominance simply to the fact that the
Smokies are a special area. Lack of disturbance, and lack of
continued disturbance, climate, geology, and the resultant high
diversity all work in favor of the site. The other part of the smokies
dominance is probably an artificial artifact of how we have set up the
situation. The NC side of the park contains several distinct high growth
areas that are separated by areas of shorter forest with different
growing conditions, and the high growth regions
are spatial separated by a few miles. If not for the park boundary, we
would probably see the area as having several distinct
superlative sites rather than one large, incomparable site. The other
human factor is the paucity of data we have form the NC
piedmont and costal plain. Will Blozan has just recently found one
excellent piedmont site giving a specific example of the regions
potential. How tall can sweetgum, loblolly pine, cherrybark oak, and
shumard oak grow in the state's floodplains.

Bob's reply:

Agreed. The Smokies contradict the pattern. Taking in such large areas
is a political convenience that can lead us to make apples
to oranges comparisons. We need to take many sub-regions of the Smokies
to give a more accurate picture of what sites yield
that are defined more on ecological considerations.

Jess said:

Zoar Valley's dominance in New York points to some holes in this theory
and the spectacular nature of the site. New York has
several distinct regions, yet Zoar Valley appears to include excellent
habitat for all of the tall hardwood species in the state.
The lack of conifers makes the sites dominance more impressive, but
reinforces the fact that the second tier of tall species really
is not that much shorter than the tallest group of species.

Bob's reply:

With our beginning searches of the Hudson River Valley that could extend
to NY City and Long Island, Zoar's Rucker index
dominance will almost assuredly diminish a bit, but like Mohawk, will
retain a commanding lead. In searching for other
New England super sites, it will be interesting to follow the trends on
a state by state basis. The results may be more along the
lines of curiosities than science, but at the least, I think many useful
observations will be made. For instance, the historical land
use patterns in New England, the relatively infertile soils of the
central and eastern parts of the state, the overall cool climate, the
average forest age, and the species involved, load the odds in favor of
higher site index values for the Connecticut River Valley,
the Berkshire plateau, the Housatonic River Valley, and the Taconic
uplift, but the degree of dominance of a single site in the
Berkshire province still surprises me. I see Mohawk as an anomalie.
Nothing I've seen elsewhere in Massachusetts suggests another such high
Rucker index and small differentail between the state index and Mohawk.
Mohawk, then, seems to be a significant statistical outlier. Think what
I'm searching for is predictability: for a state as a whole based on
accumulated species knowledge, for the maximum of any single site, for
typically good sites, etc. The Zoar Valley and Mohawk supersites give us
something to ponder and may provide extra ammunition to seek extra
protections for them. Still lots to think about and discuss.

Jess concluded:

Enough half thought through rambling.

Bob's concluding shot:

Jess, I fear that half thought through rambling is what I do best. But
as ramblings go, your's are far better organized than mine.


Robert T. Leverett
Cofounder, Eastern Native Tree Society
Re: Jess and Bob Colloquy   Edward Frank
  Nov 17, 2004 14:56 PST 

Bob,

These analyses are excellent. I find the arguments well thought out and
each make valid points. At the risk of stating the obvious I would like to
add a couple of numbers into the pool.

Massachusetts:   7,840 sq mi
South Carolina: 30,109 sq mi
Pennsylvania:    44,817 sq mi
Great Smoky Mountains National Park: 815 sq mi

Mass, Conn, & RI combined: 13,730 sq mi
Mass, Conn, RI, VT, & NH combined: 31,888 sq mi

In Pennsylvania the state Rucker Index is made up of trees from three
specific areas: Cook Forest State Park, Wintergreen Gorge, and Fairmount
Park. 5 1/2 Massachusetts could be fit into PA. In a reasonable division
of the state into 6 Massachusetts sized parts, it is likely that each of
these areas would be in a separate section and each would dominate the
Rucker Index for its segment, much like MTSF does for Massachusetts.

In South Carolina, most of the Rucker Index numbers are from two areas:
The Brevard Fault Zone and Congaree Swamp National Park. If you broke
South Carolina into 4 Massachusetts sized areas, these could very well be
in separate sections and would appear to be a one-site dominant pattern.

The Great Smoky National Park is somewhat of an anomaly, but I should point
out you have 815 sq miles of nearly continuous 70 year old forests. They
have not been timbered as most of the square miles of forest found in the
other states. I don't have anyway of determining how many square miles of
forest in these other areas have not been timbered since the 1930's. I
would also like to note that GSMNP contains a very diverse habitat, with a
higher average annual rainfall than the other areas under discussion.

Ed Frank
RE: Jess and Bob Colloquy   Robert Leverett
  Nov 18, 2004 08:21 PST 

Ed:

    The local maximum tree height model that is emerging as we go from
the extreme northeast New England first westward and then southward
suggests to me that bedrock geology and land use history are the
principal factors explaining the jump in heights across the states of
Massachusetts and Connecticut. The same may be true of New Hampshire,
but once the eastern border of Vermont is reached, the trend does not
apply. The eastern side of Vermont starts with the rich Connecticut
River Valley region. I'm unsure what the trend is for Maine.

     We seem to be accepting an hypothesis that larger states with more
climatic, geological, and topographical diversity will exhibit larger
differentials between the highest single site and the entire state. NY
is a case in point. After last Sunday's catch, I wouldn't rule out a
tuliptree somewhere in the Hudson River Valley that challenges the Zoar
Valley tree. I could imagine NY as a whole having a top 10 looking like
the following:


White pine         160
Tulip tree         158
White ash         142
Sycamore         140
Hemlock                 137
Sugar maple         136
Cottonwood         136
Black cherry         135
Shagbark hickory 135
Bitternut hickory 135


     These predicted heights would yield a Rucker index of 141.4 and a
differential with Zoar Vally of 5.71.

     Going southward to Cook, the differential continues to increase
with the differentail in the southern states reaching 8 to 10 points
-provided we define sites that include at most a few thousand acres.

     Speculating about where the trends are going is rather like
engaging in day to day stock market analysis, but fun.

     Next month, I plan to return to the private site in Claremont NH
with the intention of computing a full Rucker Index. I currently believe
Claremont to be New Hampshire's lone super site. The Rucker index should
be at least 120 and that is likely to be as good as it gets for either
NH, VT, or ME. The state index for all NH probably does not exceed 126
or 127.    

     I wonder if either Lee or Paul would like to go out on the
proverbial limb and predict site and/or state maximums for Minnesota,
Wisconsin, and Michigan?

Bob
RE: Rucker index   Lee E. Frelich
  Nov 18, 2004 08:37 PST 

Bob:

My prediction for Rucker indexes are 130-135 for Michigan, 125-130 for WI
and about 110-115 for MN. A collection of different sites would probably
have to be used for statewide indexes, since each super site is only likely
to include a few species that are the tallest in the state.

Lee
RE: Rucker index   Robert Leverett
  Nov 18, 2004 09:31 PST 

Lee:

For most of the species we are studying, do you think we will reach a
point in the next several years where we can use just latitude and
longitude to predict maximum indices and maximum individual species
heights across the range of latitudes and longitudes with which we deal,
with some regional spikes such as around the Great Lakes? You're a lot
better at sensing the broader trends than I am, but I think I do see
emerging from the murky mist stable trends here in my little corner of
New England, but they seem to change going westward.

   If the overall trend of the highest index sites contributing
overwhelmingly to the state maximums continues for the Northeast and
perhaps central states, do you think that we'll encounter a very
different situation in the deep South for say Louisana, Mississippi, and
Florida? Those states don't have mountainous terrain. I also expect Will
has some thoughts about site to state relationships for the extreme
southern end of the eastern forest biome. Will?

   With respect to my neck of the woods, I'm really hoping that the
mature trees on the old Hudson River estates will give us a more indepth
look at the capabilities of the species in which we are investing so
much time. But the FDR and Cornelius Vanderbilt estates reminded me on
just how much things can change from broad regional patterns to that of
specific sites. White pine grows on both estates, but is a lesser player
than usual for the latitudes. Liriodendron is the undisputed king at
both sites. It clearly outgrows the white pine and may, just may,
produce a 160-footer somewhere along the Hudson River corridor. By
contrast, by the time the Adirondacks are reached, tuliptree has dropped
out of the forest and Pinus strobus reigns supreme. Howard Stoner may
eventually pull out a 160-footer for us somewhere in the Daks. White ash
may reach a maximum toward the center of the state, e.g. at Zoar Valley.
So, we'll likely find maximums scattered all over the state. Yet Zoar
Valley will continue reigning supreme as the empire state's sole super
site.

    Now travel eastward into western Massachusetts and a single site
logs 17 state height records, with much more limited prospects of
finding new champions in other parts of the state for those species to
reduce Mohawk's dominance.

    With a developing network of tree hunters in Connecticut interested
in ENTS, it will be extremely interesting to see if it is the
Massachusetts or the New York example that extends southward - and why.

    So many factors to consider, so much fun doing it.

Bob     
RE: Rucker index   Will Blozan
  Nov 18, 2004 17:51 PST 

I suspect, even though the southern states have excellent growth rates and
growing season, that the frequency of hurricanes may negate any projected
growth maximums. Barring such wind events, I feel the Deep South would have
all the records for native trees growing there, even though it is relatively
flat. The river corridors with slight relief would harbor huge trees of
diverse species. We desperately need an ENTS rep in the Deep South. From
what I learned in forestry school, the growth rates are extreme for the
lower MI valley. But who knows? ENTS should...

Will
RE: Rucker index   Don Bragg
  Nov 19, 2004 05:36 PST 

Here in Arkansas, we are relatively sheltered from the impacts of hurricanes, so this disturbance would only prove a minor limitation to tree height. We are more impacted by ice storms and lightning strikes, both of which frequent our woods. That, and a seeming allergy to allowing stands to age past 40 years. We do have phenomenal growth rates, but few opportunities to see the long term potential of species. My work with the General Land Office survey notes and other historical data have found numerous records of 140+" diameter cypress, 80+" white oaks, 70+" tupelo and sweetgums, 60+" pine (probably loblolly), 50+" overcup oak, etc. (these were from just one county in southeastern Arkansas). Heavy logging and agricultural land clearing have virtually eliminated the old-growth, and restrain the regrowth.

On a brighter note, I plan to extend ENTS work on big (and old) tree dimensioning to the Midsouth. Our research unit will soon be purchasing a LaserPro 200LR, and I am putting together a study plan to extend height-diameter models to include champion-sized trees. Since little information on these champion trees is available, I envision spending a fair amount of time searching the woods for big trees to measure. While one person can't cover the whole area, I'll do my best to cover the region as thoroughly as possible. This portion of the Deep South may have a lot to offer, since much of the landscape wasn't subjected to decades of intensive cotton farming, and thus our sites aren't as degraded.

Don
RE: Rucker index   Lee E. Frelich
  Nov 19, 2004 05:47 PST 

Bob:

Yes, we will be able to predict maximum height from latitude and longitude
(but latitude will have the larger influence) alone. These maximum heights
are for trees growing in areas where water and nutrient supply are the most
constant (never flooded and never dry), and that either grow in areas
sheltered from wind or by chance have not been hit by high wind (using the
Midwest standard for what constitutes high wind).

Lee
RE: Jess and Bob Colloquy    Robert Leverett
   Nov 19, 2004 07:00 PST 

Ed:

    Nope, I was with you. Your points were well made and they didn't
fall on deaf ears. I'm currently thinking through what you said,
trying on different hats for size, in a manner of speaking. The role and
distribution of super sites is a fascinating line of investigation for
us to pursue and what their existence implies or may imply in terms of
forest ecology and land use history and how that combination varies from
north to south and east to west to yield a range of predictable
differentials.

    Focusing on New England as a region, we get 62,811 square miles of
land area (71,997 with water, including ocean zones). Allowing for the
possible discovery of a tuliptree in southwestern Connecticut in the
151-foot height range, New England's Rucker index would rise to 139.6.
MTSF's index is 134.5. The differential from super site to region rises
to 5.1. It is still a remarkably small differential that probably
represents the maximum regional difference we'll see for a super site of
less than 3,000 acres - the productive zone for MTSF. Now suppose
catastrophy struck Mohawk and we were left with the second site, as the
reigning super site. That site would be Ice Glen. I suppose that
southern Connecticut may have a site, hiding somewhere, in the low to
mid-120s, but not much chance of a 130. So for now, Ice Glen is it. The
differential rises to 13.4. Hmmm.

    Looking at Zoar Valley versus all NY and allowing for new tall tree
discoveries for species such as hemlock and sugar maple, the
differential between NY and Zoar Valley is between 5.0 and 5.2. Given
NY's diversity, that may be more remarkable than the New England
differential. Given its location and its forest type, Zoar Valley may be
an ecological phenomenon of first magnitude. Unique in the Northeast.

   The gap between state/region and the reigning super site widens a bit
for Cook Forest. We move up into the 7 point range - but still very
impressive.

   The story for the southern province remains to be told, but it looks
as though a larger number of super sites exist down Will and Jess's way
where most of a state's tallest species come together to produce Rucker
indices within 5 to 8 points of a regional maximum. It calls into
question how we want to define, of if we want to define, super sites, as
opposed to acknowledging statistical outliers.


Edward Frank wrote:
 
Bob,

Perhaps you misunderstand. Of course larger states will likely have
larger
Rucker indexes because of greater diversity of habitat. The point I was
making is that the smaller the state, or the smaller the area under
consideration, the more likely it will appear to have it's Rucker index
dominated by one site.

Ed
RE: Rucker index   abi-@u.washington.edu
  Nov 20, 2004 08:10 PST 

Lee et al.,
I must disagree. While latitude has perhaps the highest correlation with tree height for Eastern trees, this is a very complicated interaction with many biological and environmental factors, including precipitation, winter minimum temperature, etc.

A good predictive model will involve several variables - a model based on latitude alone (or latitude and longitude) will never be more than a rough approximation.

Thanks to great efforts over the last decade made by global modellers, much of the relevant data is readily available.

Cheers,
- BVP
RE: Rucker index   Lee Frelich
  Nov 20, 2004 18:32 PST 

Don:

We are sheltered from tropical hurricanes in MN and WI as well. However,
since we are in the Packwash derecho zone, we get winds as high as upper
level hurricanes and just as frequently as they do in Florida. So, our tall
trees are going to be found in the driftless area that was never glaciated
and has valleys several hundred feet deep that shelter trees from these
storms. The driftless area in SW WI should have trees the same height as
the MA supersite (MTSF), but no one has looked yet.

Lee
RE: Rucker index   Lee Frelich
  Nov 20, 2004 18:32 PST 

Bob:

You say you disagree, but you actually agree, since I only said latitude
would predict height for trees on sites without water and nutrient
limitations. Latitude is likely a surrogate for growing degree days or
some other physical variable, so in that sense you are right. Interesting
case where one can be right and wrong at the same time.

Much more complicated models will be necessary to predict tree height
variation caused by mineralogy, topography, and less than optimum water
supply.

Lee
RE: Rucker index   Gary A. Beluzo
  Nov 20, 2004 18:46 PST 

Lee:

Any speculation as to why MTSF is such a super site? There are certainly
boulder fields, abundant water, and the same range of TSI at many of the
other MA sites; I wonder if there is a mineral composition in the MTSF area
that is unique to that area and allows trees of many species to approach
their maxima. Because of the ultramafic bedrock there I still believe that
MAGNESIUM may have something to do with it. Do you know of published data
that suggest a correlation between magnesium levels in situ and tree height?

Gary
RE: Rucker index   Lee Frelich
  Nov 21, 2004 09:12 PST 

Gary:

I don't know of any publications on Magnesium levels and tree height, and I
don't know why MTSF is better than other sites in MA. Papers that attempt
to predict site index from soil and other factors have been very few, have
shown very limited predictability, and have been very unsatisfactory. This
field of investigation is left open for us.

Lee
A Smoky Mountain Perspective   Will Blozan
  Nov 21, 2004 10:20 PST 
ENTS,



I was interested in the Rucker Index discussions and thought I'd post the
indices for the Great Smoky Mountain National Park, estimated North
Carolina, and the entire ENTS database. GRSM is 98.39% of the estimated
state Rucker Index, and 97.81% of the entire Eastern US. All but three
species are in NC, and of those all but the eastern hemlock are in the
Cataloochee/Big Creek District. As far as the NC comparison goes, I think
the RI could be slightly higher, with taller sweetgum, cherry bark and
loblolly pine. However, such trees have not been found yet. Jess and Mike
let me know if you have taller trees. I wonder if NC or SC has the highest
ratio to the entire Eastern US. Right now, with the projected numbers below,
NC will be at 99.41%. As long as the Boogerman Pine holds strong, I think NC
will slightly exceed SC. Jess, what do you think?




GRSM

Species

White pine          186.1
Tuliptree             177.4
Eastern hemlock  168.1
White ash            167.1
Black Locust        162
Sycamore            162.2
Bitternut              156.3
Red spruce^        154.7
Sugar maple^      151
Pignut hickory^    150.9

Rucker Index=    163.58


Projected NC State Rucker

White pine            186.1
Tuliptree               177.4
Eastern hemlock    168.1
White ash             167.1
Pignut hickory       163.3
Sycamore             162.2
Black Locust          162
Loblolly pine (est)  160
Sweetgum (est)     160
Bitternut                156.3

Rucker Index=       166.25


Eastern US

White pine             186.1
Tuliptree                177.4
Eastern hemlock    168.7
Loblolly pine          167.2
Pignut hickory        168.2
White ash              167.1
Sycamore              162.2
Black locust            162
Sweetgum              157.1
Bitternut                 156.3

Rucker Index=        167.23


Will
Re: A Smoky Mountain Perspective   dbhg-@comcast.net
  Nov 21, 2004 14:32 PST 
Will:
     I was hoping you would join in and bring us up to date on NC, SC, and the GSMNP. It is difficult for me to imagine where all this is leading, but the individual statistics we've been compiling hint at a few predictable trends, north to south for super site indices versus state indices, etc. There are many areas of investigation that have surfaced since we have been preoccupied with Rucker indices.   
    Using the Rucker index, it appears that a differential of 20 to 25 feet exists at the state-region level from NC-SC to PA-NY. At this point, it isn't clear what this differential tells us, but it does serve as a reality check for anecdotal accounts of big/tall trees.
Bob
Rucker Index questions   Edward Frank
  Nov 21, 2004 18:46 PST 

ENTS,

I have been thinking about the Rucker Index (usually a dangerous thing) and
its implications. We have often in our discussions characterized it
(inaccurately) as a measurement of the tree growth potential of a
particular site based on the numerical average of the tallest specimens of
each of the ten tallest species on the site. It is a snapshot in time of
the present state of tall trees on a site.

I am wondering about how we should be dealing with trees that have died or
have had their crown broken. For example, the Boogerman Pine was 207 feet
tall in 1995, now it is 186+ feet tall. If you are looking at the
potential height that trees can grow on the site, the 207 foot height still
represents the maximum known potential for Eastern White Pine at the site,
even though the crown has been since broken. If the tree was still
unbroken, by itself would bump up the Rucker index for the site, the state,
and the Eastern United States by 2 points.

If we have trees that have died on a site, that were accurately measured to
be a greater height than the current tallest representative of that species
from that site, then they too represent a maximum known potential for the
site for that species, even if it is not reflected in the current forest
trees.

This become a more pressing consideration when we are in the process of
seeing a major tree species, the Eastern Hemlock, being decimated
throughout much of its range. It seems to be an injustice, or at least an
oversight to not have some numerical representation of these trees, because
they were real living trees representing real measured growth on that site.

When we measure trees and can see that they have grown from year to year,
the site maximum for those species is not increasing, just more of the
potential for that species is being realized.
Re: Rucker Index questions   dbhg-@comcast.net
  Nov 21, 2004 19:29 PST 
Ed:

   The approach I recommend is to keep two indices running for as site:
            HRI = Historical Rucker Index
            CRI = Current Rucker Index

    The historical index is the one you speak of. I had been thinking about doing that for the sites I monitor and spoke to Will Blozan about it earlier this evening. We must be reading each other's minds.

Bob
RE: Rucker index   Don Bragg
  Nov 22, 2004 05:36 PST 

While we are sheltered from hurricances and have less of a derecho impact, we are subject to a considerable amount of thunderstorm activity, with winds being only one of the threats. Over the last year, I have seen a large number of taller pines dying from lightning strikes--far more than I've ever seen in my years in the Lake States or the Rocky Mountains. This is probably occurring at a rate that may help limit maximum tree height in much of the South. Pines killed or injured by lightning become pine beetle attractors, and can considerably expand the impact zone. I fear we are starting to lose many of the tallest pines in protected locations in Arkansas to lightning and bugs.

Don
RE: Rucker Index questions   Will Blozan
  Nov 22, 2004 05:47 PST 

Ed and Bob,

It just so happens that I have EXCEL file on my computer that has historical
(former) RI for the Smokies. It includes two trees, the Boogerman Pine at
207' and the Tsali hemlock at 169'10". Funny how it has been in our minds
and computers for some time.

Ed, I agree fully with your discussion.

Will
HRI and CRI    Robert Leverett
   Nov 22, 2004 06:06 PST 

Ed:

    At a point in the past, Colby Rucker and I did discuss the
historical indexing concept, but at the time Colby was saturated with
the big lists that he was developing, so we didn't go forward. I just
want the record to reflect that Colby was in on the idea too.

    Going forward, extensions to a a single, encompassing index for our
most important sites might include the following components.

     1. Indices to implement both the HRI and CRI concepts,

     2. Separate sub-site indices that are defined around
        recognizable topographical and cultural features to
        include water drainages, roads, trails, forest to
        field, etc. There isn't much point in trying to
        delineate "ecological boundaries" when the concept
        is so fuzzy and sure to remain that way in all but a
        small number of exceptions.

     3. Combining the sub-sites into a single site index as
        we do now.

     4. Iteratations of the above.

   With the use of a good microcomputer database, like MSACCESS, the
above plan becomes very manageable. Individual tree measurements are
recorded based on species, location, date of measurement, measurer,
measurement readings, condition of tree, age class, terrain index, etc.
The work is all in taking the measurements instead of afterwards in
compiling multiple lists. These are implemented through stored query
definitions. This is what I presently do. What I haven't done yet is
automate the iteration process. It is semi-automated, but still requires
too much manual effort.

   With enough individual tree measurments and associated data,
collected over time, I suspect many interesting patterns and ceilings
will reveal themselves that are presently hidden from our view. The
level of understanding that our contribution brings to an in-depth
understanding of the physiology of trees may be limited in the eyes of
those who seek to reach the ultimate understanding of limits, but we'll
have compiled by far the most picture of what eastern species are doing
and where they are doing it. How important is that? From a scientific
standpoint,I don't know. I leave it to Lee Frelich and a few others to
answer that question and to direct our efforts when we go too far
astray. But from a historical and even cultural perspective, we will
have made by far the most significant contribution, a contribution that
cannot come from the current system of champion tree lists - and that is
not meant as criticism of those lists and certainly not the motivations
for the lists.

    Going from pure science to management, one "practical" use for the
Rucker indices and associated growth data (which I don't always
differentiate in these e-mails, but should), is to highlight what
various species are capable of doing over the span of a couple of
centuries of growing. Opening eyes that are presently closed to what
each species can do, given time, couldn't be more important here in the
Northeast. The pressure to cut trees at a very young age (30 to 60
years) is overwhelming in every Northeastern state. Lumbermen in
Massachusetts think they are making an enormous personal sacrifice and
doing the forest a giant favor if they let trees grow for 60 years.
That's what they think of as a long rotation. So efforts that shine the
spotlight on growth, growth rates, and overall species potential are
important to public education, which is itself important if we're ever
to implement , as opposed to talk about, real forest management.     
      
Bob
Re: HRI and CRI   Edward Frank
  Nov 22, 2004 18:08 PST 

Bob,

That sounds like a plan to me. I don't think we need to coin a new acronym
for CRI, as the standard usage of RI is fine.

Ed
Re: HRI and CRI   dbhg-@comcast.net
  Nov 23, 2004 04:07 PST 
Ed:
     Just trying CRI and HRI on for size. Maybe RI and HRI are sufficient to distinguish the to ideas. We are using RI as a predictor of HRI as well as making a statement of what is at a site at a specific time - the snapshot you were referring to. The difference of RI versus HRI over time speaks to the frequency and degree of disturbance. However, I'm not suggesting the difference as a measure that we ought to track. None of us will be around long enough for the meausre to be worth anything.
Bob