Canopy Height Measurement

Canopy Height Measurement

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TOPIC: New ideas on canopy measurement and comparison
http://groups.google.com/group/entstrees/browse_thread/thread/c618b4dd3947c6f5?hl=en
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== 1 of 4 ==
Date: Wed, Jun 18 2008 4:26 pm
From: dbhguru@comcast.net

Ed, Will, Jess, BVP, Lee, Don, Don, Dale, et al,
By what methods can we best compare forest canopy height structures? Finding an answer to this question constitutes an exercise in preparation for our planned February 2009 Congaree NP gathering. I think we need to come up with a comparison method that justifies the extra effort we'll be making in that swamp environment.
We know that measuring individual tree heights in a swamp like Congaree falls only slightly below the classification of torture. Tree measuring in a wet, mucky environment overrun with mosquitoes, harboring cottonmouths and poison ivy is a far cry from the relative comfort of a New England woodland. I can personally attest to that. Congaree will be an exercise in measuring under duress. So, we should make the most of our collective talents.
Once sufficient raw data have been collected, portraying the results in a visually elucidating way will present us with a special challenge. It occurs to me that a stimulating way of making site-to-site canopy height comparisons is to visualize a two-dimensional surface parallel to the ground and at a set vertical distance such as 100 feet. If the ground is flat, the surface will be a simple plane. If the ground undulates the parallel surface will do so correspondingly.
In terms of a visual image, think of the sight of trees sticking up through the surface. For a pre-set vertical distance and surface area, we could express the percentage of canopy trees that touch or stick through the surface. We could repeat this surface-based model for parallel surfaces at intervals of 25 say vertical feet, e.g. at 100, 125, 150, and 175. Computer graphics could provide us with a visually enhanced picture of a canopy for each surface area we chose, e.g. the one at 100 feet. Accompanying the visuals, we could list the actual counts of stems meeting height thresholds per unit area, presenting it in the familiar tabular format. A still further numeric comparative measure could be the number of separate species meeting each height threshold. We would, of course, list the absolute maximums and the overall averages for a site, but the more visually revealing story would be revealed through the surface area analysis.
Eventual side-by-side graphic comparisons for different sites would convey much information about canopy structure. I'm hoping that my buddy Gary Beluzo can find a solution for the visual comparison.
Bob

== 2 of 4 ==
Date: Wed, Jun 18 2008 9:28 pm
From: "Edward Frank"

ENTS,

I sent this comment to Bob and others a couple weeks ago along the same lines. Bob, You wrote: "Lee Frelich has a good method that utilizes parallel transects. He perfected the method in the Porcupine Mtns years ago. So there is no need for us to reinvent the wheel. Now, putting the method into practice in Congaree's terrain may test our collective abilities and patience, and tolerance to getting wet, but that's what the top-of-the-line ENTS troops are all about. "

I am wondering when you look at photos of the canopy at most sites you see a few emergent tree extending from the fairly uniform canopy. I am wondering if a different approach might be done that allows us to utilize the climbing abilities of our President and others. From an emergent tree, climb upward until you break through the general canopy top into the emergent section of the tree. Measure the height of the tree at the point it emerges from the canopy. If there were two climbers, looking back and forth between two tree some distance apart would allow them to better define the point at which at which each tree breaks out. This would be an approach that would characterize the canopy over a broad area rather than those of trees along a transect.

I don't think this is reinventing the wheel, but an approach with a different set of strengths. It is in some ways similar to the 3d space mapping that Roman Dial has been doing in tropical tree canopies, but only looking at one aspect of the space - the top of the general canopy. From a fixed point in the tree, as measured with a tape drop, the laser and clinometer could be used to measure the height of various trees in the surrounding area, ignoring ground surface variations, and the variation between high and low spots in the canopy surface could be calculated. It would perhaps provide a different perspective on canopy structure than would be generated by the transects.

Ed Frank

Bob's trupulse or similar equipment would allow the quick measurement of dozens of trees in the area surrounding the emergent tree and allow a contour map of the canopy to be generated. It could be done with the basic clinometer, rangefinder, and compass. The top of each tree could be plotted in 3d-space.

== 3 of 4 ==
Date: Wed, Jun 18 2008 10:18 pm
From: DON BERTOLETTE

Ed/ENTS-
ENTS may be approaching a point where it, or entities within it, obtain grant support for such efforts.
I would think that Lee's parallel transects method, located in a statistically valid random fashion could provide ground-truthing for remotely sensed aerial/satellite photography/digital imagery.
Obtaining existing current or archived aerial photography (stereo paired) would be relatively inexpensive and immensely helpful in getting the lay of the 3D 'canopy land'. Getting geo-rectified aerial photography would be better, but might be more difficult to access. Digital imagery, whether aerial platform or satellite based, with high resolution (spectral and spatial) would be the cat's meow. These all, or part, may already exist, and be available to either gov't agencies, and/or universities, at little or no cost.
Entry of all these layers (vertical and conceptual) into a GIS (spatially related database), and the analysis that a GIS would inable, would absolutely elevate ENTS accuracy efforts to a world class level.
Grant support would go along ways towards enabling such an effort, and may be easier to obtain than many might think.
February could be too soon for completion, but appropriate for collection of ground-truthing data.
Just a few thoughts on this matter...
-DonRB

== 4 of 4 ==
Date: Wed, Jun 18 2008 10:23 pm
From: DON BERTOLETTE

Ed-
Even if the high-tech/remotely sensed solution were too much too soon, at a bare minimum, efforts to obtain stereo paired aerial photography would be an incredibly appropriate technology for viewing/analyzing emergent crowns, well in advance of actual climbing/February.
-DonRB

== 2 of 11 ==
Date: Thurs, Jun 19 2008 10:16 am
From: DON BERTOLETTE

Gary-
While at a Diamondbacks game inside Phoenix's Chase Field, I watched a miniature "zeppelin" remotely controlled, cruising through the stands, with the ability to navigate 3D space amazingly well...could this be a future ENTS webcam-mounted 'drone'?
-DonRB

== 3 of 11 ==
Date: Thurs, Jun 19 2008 10:25 am
From: "Gary A. Beluzo"

Question is, how small can they be made? I could see an entirely new
dimension opening up for ENTS. Perhaps Paul Jost can whip one up?
What say you Paul?

Gary

== 4 of 11 ==
Date: Thurs, Jun 19 2008 11:34 am
From:

It's probably already been done. All it will take is a requirements specification, some money, and a little development time...

PJ

== 5 of 11 ==
Date: Thurs, Jun 19 2008 12:43 pm
From: DON BERTOLETTE

Gary-
The ones I've seen were at a distance but appeared to be about human dimension...maybe 6' long, 1.5' diameter?
-DonRB

== 6 of 11 ==
Date: Thurs, Jun 19 2008 2:03 pm
From:

I wonder how much weight that they can support - for a camera and possible a radio...

PJ

== 7 of 11 ==
Date: Thurs, Jun 19 2008 3:24 pm
From: "Gary A. Beluzo"

It would be pretty cool, ENTS could use it as a primary tool to study
canopy texture, map relative tree heights, etc.

Gary

== 8 of 11 ==
Date: Thurs, Jun 19 2008 3:41 pm
From: "Gary A. Beluzo"

Army surplus stores sometimes sell 3 meter balloons..helium has a
lifting force of 1 gram/liter so:

4/3 x pi x 150 x 150 x 150 = 14,137,000 cubic centimeters = 14,137
liters of helium

which can lift about 14 kilograms or 30 pounds!

Gary

== 9 of 11 ==
Date: Thurs, Jun 19 2008 4:08 pm
From: DON BERTOLETTE

Paul-
I didn't know...so with a little internet searching, I can't answer you directly, but I'm optimistic that what we're looking at could be done. There are an array of blimps that can be controlled remotely (usually by radio transmitter/receiver), ranging from 3' to 30' or more. Some are designed for outdoors, and like the ones I've seen at Chase Field, some are designed for indoors.
So far, most have appeared to be of mylar like construction for lightness, and I don't know how pressurized mylar balloons would fair in the forest.
But they appear to have the capacity to maneuver with controls over left/right, up/down, yaw, etc., and lift webcams and such...there are also R-232 connectibility, so data transfer would seem to be realistic.
There's enough out there (a surprising number of ex-military enterprises are availing their skills) that it would be reasonable to look further, should interest be sufficient...
-DonRB

== 10 of 11 ==
Date: Thurs, Jun 19 2008 4:11 pm
From: "Gary A. Beluzo"

AP Boston. This is an image of Bob Leverett 1000 feet above Mohawk
Trail State Forest in Charlemont, MA.
Leverett was trying to measure and photograph the tallest tree in New
England, the so called "Jake Swamp Tree",
a white pine, when he and his equipment starting rising above the
canopy. Bob exclaimed on the way out of the canopy,
"I thought I had enough frigg'n ballast with all these frigg'n
instruments attached to my waist...."

Onlookers called the Mass State Police and they arrived on site about
2 hours ago. They continued monitoring Leverett
with binoculars and then a telescope as he rose higher and higher
above his beloved Jake Swamp Tree.
The U.S. Air Force has just picked him up on radar and plans are being
made to make a dangerous rescue by shooting out some of the
helium balloons with heat-seeking rockets. Bob is now at some 15,000
feet above the ground and was heard by one of the pilots
yelling "my frigg'n instruments are frozen, get me down!

Army surplus stores sometimes sell 3 meter balloons..helium has a
lifting force of 1 gram/liter so:

4/3 x pi x 150 x 150 x 150 = 14,137,000 cubic centimeters = 14,137
liters of helium

which can lift about 14 kilograms or 30 pounds!

Gary

== 11 of 11 ==
Date: Thurs, Jun 19 2008 4:14 pm
From: DON BERTOLETTE

Gary-
I don't like his odds for getting up through a closed canopy...:>)
-DonRB

== 2 of 2 ==
Date: Thurs, Jun 19 2008 6:15 pm
From: dbhguru@comcast.net

Gary,

Dangnab it! My feet are still frozen along with my butt. Monica is administering warm packs. However, my friggin gadgets seem to be permanetly frozen to my midsection. Any suggestions?

Balloon-man Bob

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TOPIC: [Fwd: New Images - Tree Canopy Height from 1650 to 1992]
http://groups.google.com/group/entstrees/browse_thread/thread/7acdd885872b8d59?hl=en
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== 1 of 4 ==
Date: Thurs, Jun 19 2008 5:10 am
From: neil

Hi All,

This came across my desk the other day. Thought it might be a topic of
interest for ENTS.

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17913

neil

== 2 of 4 ==
Date: Thurs, Jun 19 2008 7:27 am
From: "Edward Frank"

Neil,

I think it is amazing they were able to find satellite photos and air photos from 1650, 1850, and 1920 to generate those maps.

Ed

== 3 of 4 ==
Date: Thurs, Jun 19 2008 7:35 am
From:

Ed,

I've heard that the pre-Columbian mound-building cultures were far more advanced than originally thought. It is possible that they mis-dated the old imagery and it is actually much earlier than they had disclosed!!! ;)

PJ

== 4 of 4 ==
Date: Thurs, Jun 19 2008 9:06 am
From: "Gary A. Beluzo"

Was that the DaVinci helicopter that was used for the 1650 air photos?

G

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TOPIC: Those no good lazy ecologists and measuring forest structure
http://groups.google.com/group/entstrees/browse_thread/thread/24263f51fdac4d84?hl=en
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== 1 of 2 ==
Date: Thurs, Jun 19 2008 3:35 pm
From: shamrock94@aol.com

Bob, Don et all,

This is in response to some comments made in regards to Don's early days in the FS-

I am just a field grunt not a trained ecologist, but I can confirm that tree heights often do not get measured accurately. In?fact when I was out west we did not measure them at all when conducting veg surveys on our carnivore survey sites. We?measured dbh, species composition, and canopy cover along with course woody debris.

The bigger issue is that I doubt much of the data we collected ever truly got analyzed in a rigorous way. It is very difficult to break all those numbers down into useful categories that can be compared to the main variables we were looking at which were?biodiversity in relationship to development and recreation.

I don't think tree height is all that important of a variable when it comes to most wildlife. However forest composition and structure is key. I would be interested in working with some of you to develop?a way to gather?veg data that can be looked at in conjunction with wildlife studies. The key is that it has to be really focused, field quick, and easily analyzable.?I have several ideas and a protocol that I have been slowely evolving. I also have a?growing picture of how forest stucture and different habitats effect many larger mammals.?But I do not have the statistical knowhow to figure out how to deal with all those?plant species and numbers.

Tim

== 2 of 2 ==
Date: Thurs, Jun 19 2008 3:45 pm
From: "Gary A. Beluzo"

Tim,

As a systems ecologist, I would be interested in seeing ENTS explore
and describe methods on composition, structure, texture, etc (i.e.
delve into the QUALITATIVE side of things). I enjoy measuring trees
but I think we also need to explore methods to describe GROUPS of
trees, stands, forests, etc.

So, do we need a DENDROMORPHOLOGY branch to complement the
DENDROMORPHOMETRY roots of ENTS?

Gary

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