- TSI and Height Density Calculations
29, 2005 08:24 PDT
Yesterday Gary Beluzo, Susan Scott, and
I went to the northern part of MTSF that we call the Shunpike
area. One spot called Shunpike flats has a cluster of tall ash
trees, the champion American basswood, and a scattering of other
species. One the way to the flats, you pass through an area that
has a small grove of bigtooth aspens, and a lot of N. red oaks,
mixed with birch, maple, and ash. One N. red oak is at the
bottom of a ravine and has been growing well over the past
several years that we have been measuring it. While Gary and
Susan computed a TSI for the area, I remeasured the tree. It is
a skinny 6.9 feet in circumference and a cool 131.3 feet in
height. It now joins the over 130 club of northern reds.
On Shunpike flats I confirmed two of the
previously three measured 140-foot ash trees in the general
vicinity. The dimensions of the ash trees are (141.5, 7.6) and
(143.2, 5.6). The (141.5, 7.6) was not previously included as a
140-footer, so it becomes #16 for MTSF in that height class.
The height density determination was labor
intensive. We established a circle that was 35 yards in radius.
That produces an area 0.795 acres. The following is the tally of
trees in the plot by the height classes >=100, and <100.
Species >=100 <
White ash 21 2
Sugar maple 5 7
N. red oak 2 5
White pine 1 0
Red maple 1 0
B. nut hickory 1 0
A. basswood 1 1
Yellow birch 0 5
Bigtooth aspen 0 1
Black cherry 0 1
A. beech 0 1
Totals 32 23
Projected to an acre 40 29
The 69 canopy trees in the projected
acre is a light distribution for other areas of Mohawk. I would
say that the average number of trees per acre in Mohawk would be
between 90 and 100 - based on other samples I've taken. I think
there are between 600,000 and 700,000 trees that form the canopy
of MTSF. I suppose the number could go as high as 800,000, but I
doubt any higher.
This is just a first crack at
computing height/diameter densities. It is a lot of work and I
would be inclined to settle on a radius of 28 yards. That would
represent a half acre area. Just a little more manageable.
However, I can't quite see doing this kind of analysis in an
area choked with mountain laurel or some other dense shrub.
Certainly not rhodo.
Aspens and Measurement Plots
31, 2005 10:14 PDT
I usually make a gut-feel call on the clonal
aspect. If the aspens
are clustered together I suspect that they reproduced clonally.
pretty loose rule. In other words, I'm making an educated guess.
can address the clonal aspect and how frequently it explains
in different environments.
On Saturday's height-density exercise, we
included all trees in the
plot which was centered within an old, flat forest opening, an
that produced the flush of white ash growth. We spent only
with each tree to determine if it was above or below 100 feet.
often do this shooting straight up. If we couldn't verify 100
shooting straight up, we went to greater lengths to determine a
in or out status.
Determining the limits if the plot required no
more than shooting to
the trunk of each tree that was near the circumference of the
chosen. We chose 35 yards which included a convenient tree at
boundary of a boulder field. We didn't want to have to negotiate
In applying the above method, we immediately
saw that some trees were
obviously inside the circle and others obviously out. If there
question, of course you shot the tree. Foolishly I did not note
starting time for the measuring, nor the ending time. We will be
meticulous on the next effort.
I chose the area for ease of measurement
(low tree density and flat
terrain) and because it included two distinct populations. One
population is that of older dominant trees which began
opening about 80 to 100 years ago and a second population of
trees that have grown up under the canopy of the originals.
The appeal of MTSF is in its diversity
of forest types, age
structures, and disturbance histories. There are numerous
for us to pursue. We can study: (1) multi-aged stands that
developmental histories (primary and secondary OG), (2)
stands (white pines) in at least 3 age classes, (3) stands with
classes, an old uniform-age class of pioneer species that
younger settler species of a continuous age distribution up to
50-60 years, and (4) young multi-species stands of 70-80 years
The ultimate goal is to develop an
efficient method for developing
height-diameter density curves. Ideally, we document each tree
(2) Exact height
from center point of plot
(6) Age class (
0 - 100, 101 - 200, > 200)
(7) Slope angle
(8) Form type
(open growth, partially open grown, forest grown)
(good, fair, poor)
is the most time consuming calculation. If everything
works out, we may be able to put in a plot using the above
Sunday. We'll opt for a fairly flat site.
addition to the above, we will get GPS coordinates (lat,
long, alt) for the center of the plot (if possible) along with a
site description. We will note start and finish times and the
each participant. Wish us luck.
Frank wrote (May 30, 2005):
You and others have talked about groves of clonal
aspens. I am wondering
how you can tell if the aspens are clonal grown from
root spreading or
whether they were sexually reproduced?
Clonal Aspens and Measurement Plots
31, 2005 11:14 PDT
Often you can see aspens that all turn color at the same time or
the same color in the fall all in one patch, and it is highly
the color patches indicate clones. Other than that you need to
the root system or do genetic sampling to see if a patch of
aspens are a
clone. For other tree species clusters are usually caused by
effects other than root sprout clones.
Regarding the height density curves, I am not sure what your
which makes it hard to tell if you are need to measure anything
modify your procedure. I assume your 10th variable is crown
(dominance), so that each tree would be dominant, co-dominant,
Clonal Aspens and Measurement Plots
31, 2005 11:49 PDT
My original intention was to begin laying the
groundwork for going
beyond the current Rucker index concept by providing another way
profiling the "tallness" of a forest. Number or
density of trees over a
height threshold per unit area was the initial idea. I knew we
classify a tree as over or under a height such as 100 feet with
minimum of effort. So I began there. But where time permitted,
the extra step of accurately measuring the height of each tree,
realized we could better see/classify the stratifications of the
canopy. I then extended this idea to include circumference (or
and the other variables to more completely profile what the
doing at a site. I visualized the problem as one of going from
collecting a minimum of data to a maximum in some hierarchical
For our best areas of our best sites we would collect data on
variables. Sampling would be for all the variables in the forest
cathedral of Cook, one of the pine stands or Ash Flats in
most productive terrace in Zoar Valley.
I'd like to look at the tradeoffs in terms of
time/labor needed to
collect data across the range of variables. Apart from what we
doing under your direct supervision, periodically I try to think
ENTS as a broader group can be doing in terms of building a
that reflects site data and range-wide species data.
When Ed raised some valid concerns about the
utility of multiple
iterations of the Rucker index, I realized that my enthusiastic
of the process masked what I actually do when looking at a site,
that in actuality, computing Rucker indices convey only part of
most of us do when profiling a site. My purpose is to
paint as accurate of a picture of what is structurally going on
site as I can through the use of numbers. Height density
occurred to me as the next step in the direction I was heading.
The latest couple of e-mails extended the
simple design of density of
trees by species over 100 feet to arrive at the Cadillac of the
Of course other measurements could be thrown in to include crown
and coverage, but I am less comfortable with crown measurements
than the relatively simple crown spread calculations I
Before the advent of our laser rangefinders, a
thorny measurement has
been area measurements. But for circular area, determining trees
fall within or outside a circumference is very easy. Efficiency
the use of a two-person team. That's what I want to experiment
come up with a reasonable range of times for a half-acre plot.
should be able to advise others on the amount of labor that is
to take the kinds of site measurements that we take. At least
that is the
predilection of those of us with engineering backgrounds. I
thought I'd be advocating the use of the old stopwatch.
ENTS tree measuring. Uh, I have a feeling that some of my
trees, right now, are doing the tree equivalent of throwing up.