| RD
1000 Relascope/dendrometer: Viva
La Modeling |
Robert
Leverett |
|
Aug
08, 2005 06:05 PDT |
ENTS:
Saturday and Sunday was devoted to
tree modeling using the RD 1000
Relascope/dendrometer. Beyond the simple diameter at breast
height
exercises that I had satisfactorily done, the weekend's modeling
projects were my first real opportunities to see just how well
the
device works on whole tree modeling, both with and without a
tripod. I
tackled the Ice Glen Pine, solo, on Saturday without a tripod.
Monica
communed with the trees and rocks of Ice Glen while I measured
the huge
Ice Glen pine. Then on Sunday John Knuerr, Susan Scott and I
modeled the
Jake Swamp white pine in MTSF using a tripod. In terms of the
ease of
use of the RD 1000, I'll cut to the chase. It is accurate as
advertised,
but lots of technical/practical considerations make modeling a
whole
tree much more complicated than just shooting a diameter at
breast
height plus one or two upper trunk measurements. Please be
forewarned.
The process is labor intensive. For starters, intervening
branches from
nearby trees as well as the target tree can obscure the trunk at
key
height intervals and require frequent changes of vantage point.
It
became very apparent that use of the included magnifier lens is
necessary to adequately see the trunk in many if not most
situations.
However, built-in limitations on how wide the scale can be
expanded
means that if you get too close, you can’t cover the entire
trunk, so
you must change vantage points to get the benefit of
magnification.
One thing is absolutely
certain, you can't take too many
cross-checking measurements. If you accept one measurement at a
particular height, then you are fooling yourself about accuracy.
Unfortunately when starting out it isn't obvious what the best
measurement plan is for a tree unless it has been thoroughly
scrutinized
beforehand. So expect some false starts. Also, better have a
good tripod
that allows delicate movements both laterally and vertically.
The tripod
we used was difficult to move horizontally. It did so in fits
and jerks,
which was not good for aligning the diameter scale against the
trunk.
The problem elicited some choice mumblings from me - under my
breath of
course.
Anyway, I computed 42
diameters for the Ice Glen pine, but used
only 16 sections. Many of my first measurements were taken from
too
great a distance when I was trying to see the whole tree. I
eventually
had to move much closer and use magnification. John Knuerr and I
used 18
measurements for the Jake Swamp Tree. Susan Scott took some of
the
measurements and we also had a UMASS student participating.
So what did we get? I’m
pleased to announce that Jake's volume is
about 660 cubic feet. That isn’t much different from some of
my early
cruder calculations. However, I am elated to announce that the
Ice Glen
pine is an impressive 1204 cubic feet. This was a surprising. I
did
think it would make 1,000, but not 1200. So, the Ice Glen pine
is a true
giant. BTW, its circumference at 4.5 feet is now 13 feet even.
That may
be in part a result of be giving the big tree the benefit of the
doubt
as to base point. An older spotting of the base would have
produced 12.9
feet.
By contrast, the circumference of
Jake, which is about half the age
of the Ice Glen pine, is a solid 10.4 feet. So the difference of
2.6
feet in circumference and the Ice Glen’s more columnar form
makes a heck
of a difference. No surprise there. Incidentally, the Ice Glen
pine's
height was measured at 153.3 feet. It is growing more slowly
than Jake.
What are the odds that we would be
at the Jake tree and not measure
its height? Foolish question. John Knuerr and I measured Jake's
final
season height at a cool 167.3 feet and we did it from an
entirely new
location. So I'm very satisfied that Jake's height is rock
solid. We’ve
measured and re-measured using different equipment and measurers
from
different locations. Jakes vital measurements can now be
recorded for
posterity.
As of August 7, 2005:
Full Height ---------------
167.3 feet
DBH
-------------------------- 10.4 feet
Max Crown spread
-------- 46.0 feet
Trunk and limb volume
--- 660 cubic feet
Approximate board feet
-- 660 x 12 x 0.50 = 3960 bdft (The
assumed 50% usage is my guess. That might be a little low. I
defer to
our foresters to provide a more realistic conversion factor.)
Measuring Team:
Robert Leverett
John Knuerr
Susan Scott
Observer:
Martha Jorz, UMASS
student
I presume the huge Ander's Run
white pine in PA will top 1200 cubic
feet and the Seneca Pine in Cook Forest will approach 1,000
cubic feet.
The Tamworth pine in NH will certainly top 1200 cubic feet. The
Bradford
Pine in NH will top 1000 cubic feet. The other huge 12-foot plus
circumference white pine in Cook Forest may go to 1,000 cubic
feet.
So at present, we have a handful
of great whites in the Northeast
that will make the magic number of 1,000 cubes.
Bob
Robert T. Leverett
Cofounder, Eastern Native Tree Society
|
| Re:
Viva La Modeling |
abi-@u.washington.edu |
|
Aug
08, 2005 07:11 PDT |
Bob,
That is super good news. It sounds as if the problems you had
were not necessarily with the equipment but you getting used to
this type of procedure. That is very encouraging.
Yes, it is a time-consuming process, but the results are totally
worth the effort. Sweet!
The system I use is no longer in production - it sounds as if
this is its replacement. I can't wait to try it!
Cheers,
- BVP
|
| RE:
Viva La Modeling and answer to BVP |
Robert
Leverett |
|
Aug
08, 2005 07:50 PDT |
Bob:
Yes, you are absolutely correct. I haven't had
any problem with the
RD 1000 itself, just getting used to the procedure needed to
cover as
much of the trunk as can be covered from ground level. I have
abandoned
any thoughts of a standard measurement protocol in terms of
taking
diameters at regular intervals. I can see that each tree must be
approached individually. However, at present, I'm extremely
inefficient.
But the possibilities are exciting. The unit works whether held
vertically or tilted, so I can finally measure limb thickness,
which is
really exciting. Ideally the unit would be combined with the
Lasertech
rangefinder and download capabilities into a computer.
As you may guess, the big sycamores of New
England and New York are
our long run modeling objectives. However, without a lot more
practice,
at this point, I fear that I'd badly butcher measurements of any
of the
big sycamores. John and I plan to take digital images, number
the limbs
and work from there.
For the present, John and I have decided that
our next challenge will
be a huge single-stemmed pine in Bullard Woods. It measures 13.8
feet at
breast height and is a respectable 131.3 feet tall. It has large
limbs,
so its volume should be substantial. I'm guessing that it will
go
between 900 and 950 cubic feet. We select the big pine as our
next query
because of its accessibility.
Bob
|
| RE:
Viva La Modeling and answer to BVP |
abi-@u.washington.edu |
|
Aug
08, 2005 08:09 PDT |
Bob,
There must be something a little different in your unit than
with mine. With mine, the unit must be vertical, otherwise the
distance and angle calculation will not come up with the exact
distance and height off the ground. Tilting the unit would ruin
this number. I have used it to get things slightly off vertical
by keeping it vertical to get the distance and height, and then
rotating it to get the caliper measurement.
You unit must operate differently, and if so, it will prove to
be even more useful than I initially thought.
Cheers,
- BVP
|
| RE:
Viva La Modeling and answer to BVP |
Robert
Leverett |
|
Aug
08, 2005 08:31 PDT |
Bob:
Basically, I have a routine that I tried only
once. I first compute
the distance to the center of the limb where I want to take the
caliper
measure using a laser rangefinder. I then lock that center point
distance into the RD 1000 unit's diameter routine. I treat the
center
point of the limb also as the base angle, since I'm not going to
tilt
the unit up or down. I'm just going to take the diameter at that
spot. I
then tilt the unit and cover the diameter of the limb with the
expand-contract buttons and read the result as the diameter of
the limb.
I am embarrassed to say I didn't check the results of my one
time test.
I just wanted to confirm that I could use the unit that way. A
representative at Laser Tech had told me that the unit could be
used in
such fashion. Tonight will be for further testing with results
reported
tomorrow.
Bob
|
| RE:
Viva La Modeling |
Will
Blozan |
|
Aug
08, 2005 10:55 PDT |
Bob and friends,
I am intrigued by the numbers for the Ice Glen Pine and would
like more
detailed info about diameters aloft. I am puzzled by the
"fact" that the
Medlin Mountain Monarch hemlock in South Carolina, which is
14'7" in girth
and 162' tall is so much smaller than the Ice Glen Pine.
Something is fishy,
and the smell needs to be found!
I have very serious doubts about the size we calculated for the
Yonaguska
Hemlock. Thorough examination and extrapolation of some of the
other
hemlocks will yield some ideas. Jess is looking over some
numbers as well.
Fun, fun, fun!
-------------------------------------- |
| RE:
Viva La Modeling |
Robert
Leverett |
|
Aug
08, 2005 13:08 PDT |
Will:
If you recall, the Tsali Hemlock was a good
deal skinnier than the
Yonaguski hemlock and it went over 1000 cubes. Anyway, here are
some
data points from the trunk measurements.
Hgt up trunk Diameter at Hgt Volume
of increment
0.0 4.8
4.5 4.1 70.1
53.0 3.8 594.6
72.0 3.2 199.8
90.0 2.5 115.4
135.0 1.4 138.0
143.0 0.2 4.8
153.3 ??? ???
Limb
allowance 6.5%
Total
Volume 1201.0
The additional measurements reveal
"fat" areas of the tree due to
old limb whirls and when added to the above table add 3 feet in
volume.
It is obviously the columnar form of the tree that contributes
to its
volume. I think this is what caught Bob Van Pelt's eye when he
saw the
tree in Oct 2001.
Of course there is another
explanation, namely that I screwed up
badly with my new toy. I certainly wouldn't rule that
possibility out.
The first weekend I have free, it will be back to Ice Glen I go.
I trust
your judgment and if you don't see that much volume in the tree,
there
probably isn't. I do believe it exceeds a thousand cubes though.
Bob
|
| RE:
Viva La Modeling |
Will
Blozan |
|
Aug
08, 2005 14:14 PDT |
Yo
Bob,
I don't necessarily doubt the 1200 ft3, but rather the less than
1K on the
SC tree. That is what is "fishy". Sorry for the
confusion...
I'll add the diameter aloft dimensions below of the SC tree. The
SC tree is
consistently larger but our previous calculations place it over
18% smaller!
Hgt up trunk Diameter at Hgt Medlin
MTN
0.0 4.8 6.4'
4.5 4.1 4.7'
53.0 3.8 3.4'
72.0 3.2 3.3'
90.0 2.5 2.7'
135.0 1.4 1.8'
143.0 0.2 1.15'
153.3 ??? 0.6'
+9
more feet!
Total Volume (no limbs) 1123.0 912.0
|
| RE:
Viva La Modeling |
Dale
J. Luthringer |
|
Aug
08, 2005 17:19 PDT |
Bob, Will,
It's interesting that the Ice Glen Pine comes out to ~1200 cubes
at 13ft
CBH x 153.3ft high. It makes me wonder what the Cornplanter Pine
in
Anders Run would make for cubes at 13ft CBH x 167.1ft high... I
would
think that it should certainly go to ~1200 cubes also.
No Bob, I'm not quite ready to go out and by new modeling gadget
just
yet.
Dale
|
| Re:
Viva La Modeling |
Don
Bertolette |
|
Aug
08, 2005 18:25 PDT |
Bob-
Continuing our earlier discussion of modeling by RD1000, I
think what I was
trying to get at, and failing totally was the successive
measurements going
up from the base. Each successive measurement (and I was
thinking too, of
measuring from one spot) would be taking an increasingly angular
frustrum of
a cone...you're right in that the far left and far right side of
the tree
are still the same breadth no matter what angle you measure
from. But as
you go further up the tree, (I'm assuming you're shooting a
distance reading
at the same plane), your front of tree distance is increasingly
further from
the line described by connecting far left from far right sides
of tree (the
"section" you're modeling "diameter" from.
In reviewing this, I'm not sure I described this clearly, but
let's call it
a start!
-DonB
|
| RE:
Ice Glen vs Medlin Mountain |
Robert
Leverett |
|
Aug
09, 2005 05:11 PDT |
Will:
I ran the numbers you included below for the
Medlin Mountain Hemlock
and I get 1310 cubic feet before allowance for any limbs. Adding
6% for
limb volume gives 1394 cubic feet. Very impressive! I'm sending
a copy
of the spreadsheet to your regular e-mail address so you can see
what I
did. That puts the Medlin Mountain tree at about 193 cubic feet
more
than the Ice Glen tree. I'm surprised it isn't even more. I had
used
6.5% for limb volume for the Ice Glen tree. If I use 6% then the
Ice
Glen tree weighs in at 1194 cubic feet and the difference
between
volumes is 199 cubic feet. I somehow have a feeling that the Ice
Glen
tree is actually around 1175. Don't ask me why I think this. I
just do.
As soon as I can free up another day, it is
off to Ice Glen I go to
refine the Ice Glen tree's measurements with the tripod Monica
has lent
me.
Although Monica and I have been together only
a few months, she has
become indispensable to my ENTS efforts. The RD 1000 was a
birthday
present to me from her. The tripod she is lending me is a good
one, so I
won't have the problem I had on Sunday. Then there is the ENTS
concert
she is planning for us. Life is good.
Bob
|
| Answers
for Don Bertolette, Bob Van Pelt, and Will Blozan |
Robert
Leverett |
|
Aug
09, 2005 06:18 PDT |
Don, Bob, and Will:
Here is my latest take on the RD 1000 and
questions posed in our
discussions. Last evening a conducted the following experiment.
I put an
8.5 x 11 " sheet of white paper on the trunk of my Silver
Maple. I
positioned myself at 66 feet eye level from the center of the
paper. I
then measured the width of the paper with the RD 1000. It came
out to
8.3 inches or 0.2 inches off. Not bad! I then rotated the unit
90
degrees and measured the length of the paper. It came out to
about 10.9
inches. Success! The Laser Tech rep didn't lead me astray.
My objective was to insure that the unit
didn't possess any odd
feature in terms of unit rotation - provided the distance to the
target
is correct. Yes, that is a rub. If efficiency is what we are
seeking by
quickly scanning up and down a trunk and peeling off the numbers
as we
go, we may need to consider how the unit is calibrated.
The secret to the unit's design in
diameter mode is that it simply
provides a bright scale on a screen that is calibrated to change
to
reflect a width in inches or centimeters at a known eve level
distance.
A built-in tilt sensor then allows distances to be recomputed as
the
unit is tilted up or down. The scale then reflects the changing
diameter. The unit never sees the tree, i.e. it does not bounce
a laser
beam off the target and read the return like a laser
rangefinder. It is
all internal calculations and optics. Clever!
We need to acknowledge right off that the RD
1000's tilt meter is
calibrated for tangent-based calculations performed off the
angle of
tilt and the horizontal distance that is fed to the diameter
routines.
The unit, itself, has no way of knowing if the tree leans
forward of
backward, since it is not measuring the tree directly.
Conceptually, the
RD 1000 routines treat the object being measured like the
proverbial
vertical telephone pole in the level parking lot. That is
satisfactory
for the lower trunks of many trees, so that a quick scan of a
trunk can
quickly produce diameters via the expanded/contracted scale at
displayed
heights and allow for downloading of the data. That's pretty
slick.
However, if a tree bends in any direction, one needs to be
constantly
re-shooting distance. That is a guaranteed. Of course, that is
where the
companion Laser Tech Rangefinder comes in.
From my discussions with the Laser tech
rep, I was prepared for
shooting distances, if necessary, to the points at which
diameters would
be read. I don't mind doing a combined operation with any of my
several
laser rangefinders, if that becomes necessary. However, the
Laser Tech
rangefinder that works directly with the RD 1000 and allows
downloading
of distance directly into the RD 1000 would be the ideal. For
me, the
second unit will have to wait until I've saved my pennies, but
it is
definitely in my future. Plus, I'm getting burned out with my
less than
perfect Suunto clinometers.
Don, I'll address the parallax questions you
raise in a future
e-mail. Gotta do some more thinking about it. But to summarize
what I've
seen of the RD 1000 so far, I'm happy as a pig wallowing in
......
whatever. The only weakness in the unit that I've discovered so
far are
the skimpy instructions, especially as they relate to relascope
functions. I'm going to need some schooling from those of you
who are
foresters if I'm going to evaluate the relascope features. So,
questions
will be forthcoming. For example, I don't know what to do with
the BAF
factor (1 to 127 is allowed with the RD 1000 expressed in
English
units).
Bob
|
| More
Rd 1000 tests |
Robert
Leverett |
|
Aug
10, 2005 13:26 PDT |
Bob, Will, Don, Lee, et al:
I did manage to do another test of the RD 1000
yesterday evening. My
unit continues to measure diameter accurately whether the unit's
scale
is horizontal or vertical - provided the distance to the target
is
accurate. I discovered that at high angles, the slope scale of
my
clinometer and the tilt sensor of my Rd 1000 do not agree as to
the
slope. Now I have to check the accuracy of each at large angles
either
above or below eye level. This is troubling. If the unit is to
be used
efficiently one must be able to scan up a trunk and read off a
height
and determine the corresponding diameter with the scale. More
tomorrow.
Bob
Robert T. Leverett
Cofounder, Eastern Native Tree Society
|
| RD
1000 and beyond |
Robert
Leverett |
|
Aug
11, 2005 09:28 PDT |
Don:
Before going further with modeling and
considerations of angle of
incidence versus distance, at this point my big test is to
determine the
accuracies of the tilt sensor on the RD 1000 and of my
temperamental
Suunto clinometer. The variety of laser range finders are still
working
consistently for their part. Calibrations haven't changed.
I suspect that the internal workings of
the diameter scale on the RD
1000 will allow that feature to be consistently more accurate
when given
accurate distances than will the tilt sensor. Paul Jost
understands
those things much better than I do. Paul, any observations?
In time I may get the True Pulse Range
Finder - Inclinometer as a
companion to the RD 1000. The Inclinometer accuracy is stated as
+/-
0.25 degrees.
Bob
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