Back
to the RD 1000 |
Robert
Leverett |
Sep
14, 2005 09:19 PDT |
Will, Jess, Bob, Lee, John, et. al.:
In a catch as catch can kind of testing of the
RD 1000, I had a day
of good results yesterday in Monroe State Forest. I took the day
off for
an interview with an author and to model two trees, the huge
Grandfather
Pine in Dunbar Brook and the huge Dunbar Brook hemlock. Using
the tilt
sensor of the RD 1000, I measured the hemlock to a broken top at
118
feet. Measurements using the clinometer and laser produced 117.1
feet.
That's not a bad agreement at all. So at the distances I was
working, I
am developing faith in the accuracy of the tilt sensor. Its zero
point
differs from that of the clinometer, with the laser level being
the
ultimate arbiter of truth. But taking a trunk over an angular
sweep of
62.1 degrees, according to clinometer, the tilt sensor and the
clinometer were in close agreement. This time I didn't mix
instruments,
i.e. I didn't decide what was level according to the clinometer.
I used
the tilt sensor.
What is interesting is that I modeled the big Dunbar Brook
hemlock to
786 cubes as opposed to 750 for the Mount Tom hemlock? Can this
be
right? Well, the Mount Tom hemlock continuously tapers and the
Dunbar
Brook hemlock is a solid column for a much greater trunk length.
The
jury is out on which is the largest hemlock modeled in New
England to
date, but we've definitely got a tree race. It will take several
modelings of each tree to settle on the final numbers.
Nonetheless, I am
not expecting any New England hemlock to break 800 cubes.
I will be sending Ed Frank another test spreadsheet of the Rd
1000 in
a smaller diameter object - the round lid of a garbage can.
I'll talk about the Grandfather tree in the next e-mail.
Bob
Robert T. Leverett
Cofounder, Eastern Native Tree Society
|
Re:
Back to the RD 1000 - Level testing |
Edward
Frank |
Sep
14, 2005 18:00 PDT |
You can test the level accuracy of a clinometer or instrument.
Sight from a
marked height at some object- tree of pole at a distance. Have
an assistant
mark the point on the distant object the clinometer or
instrument says is
level. Move to that spot and sight back to your
original position. If it
is perfectly accurate the backsight will be right on the point
you shot from
originally. If it is reading high, then the angle it is off will
be
under-reading by arc tan [1/2 (error)/distance]. If
it is pointing lower
than the starting point, then it is reading high, calculations
are the same.
In this way you can tell at least if the original level line is
actually
level or not.
Ed
|
Lots
a stuff |
Robert
Leverett |
Sep
19, 2005 06:12 PDT |
ENTS:
A weekend of tree modeling
produced a revised volume determination
for the Ice Glen Pine. Its computed volume now stands at 1021
cubes and
that new determination comes via a consistent modeling
methodology. The
Grandfather tree stands at 1014 cubes, although I have
reservations
about that number. I expect the Grandfather tree will drop from
the 1000
cubes club as more and more measurements are taken. Hopefully
John
Eichholz can help me remodel the tree in late fall. My gut feel
is that
the Grandfather tree is between 950 and 975 cubes. In the chart
below,
The Tecumseh tree measurement still reflects an earlier mixed
mode
method I used and I believe the volume measurement as stated is
far too
high. Regardless, the Modeling done thus far with the RD 1000
has
produced the following results:
Tree No
No Species Name Height CBH Volume modeling Comments
1 WP Ice Glen 154.3 13.0 1021 2 Two modelings
2 WP Grandfather 145.3 13.8 1014 2 Needs another modeling
3 WP Grandmother 150.8 13.8 919 2 Moderate taper
4 WP Tecumseh 161.3 11.7 878 1 Invalid, needs remodeling
5 WP Thoreau 160.2 12.6 864 2 Trunk-BVP, Limbs-RTL
6 WP Hiawatha 141.8 12.5 856 2 3 trunks at 33 feet
7 WP Saheda 164.3 11.4 614 2 Bob L. and John Eichholz
8 WP L. Hiawatha 141.9 10.2 611 1 Needs another modeling
9 WP Jake Swamp 167.3 10.4 608 2 Needs another modeling
10 WP Amy Beech 141.0 12.8 580 1 Tapers quickly
11 WP Frank Decontie 160.1 10.1 481 1 Slender aloft
12 HM DB Hemlock 118.0 12.7 786 1 Very slow taper
13 HM Mt Tom 123.0 16.1 750 1 Tapers quickly
The RD 1000 modeling, plus what
Will Blozan and I had previously
done suggests to me that it takes a tall, 13-foot CBH conifer
with slow
taper to even have a crack at 1000 cubes. A very tall tree in
the
12.5-foot CBH range might just make it. I’m hoping the Seneca
Pine will
just graze 1000 cubes, but I’m not holding my breath.
Yesterday, at the William Cullen
Bryant Homestead, I modeled a very
large white pine with a devilishly difficult base to settle on.
Taking
multiple circumference measurements around the tree led me to
settle on
a 12.8-foot girth. However, the tree tapers fairly quickly. The
volume
determination was 580 cubes. That seems very light to me. I
didn’t go at
right angles to my first set of measurements, but I’m banking
that if I
did, the volume would come up to at least 625 cubes.
... material deleted...
Bob
Robert T. Leverett
Cofounder, Eastern Native Tree Society
|
|