We are working on a project where the client needs to know the heights of trees and/or the canopy. There are approx.. 25 trees we need to determine and they are in a heavily wooded and very hilly area. We cannot set up an instrument at any significant distance from the base of the tree and see the top which does not allow for us to use the old tangent Trig function. Any suggestions and or tools that may be useful? There has to be a forestry tool.
A drone would be perfect, but..
I take it the trees are not tall enough to be seen outside the wooded area where you could measure it with angles?
Maybe you could shoot from underneath with a relectorless?
You may need a diagonal eyepiece.
You might not get the very topmost tiny leaf, but you can get a branch and add a bit on.
I am interested if there are some foresters tricks, as this is a problem I sometimes have.
Can you get a 90 degree eye piece for a S8 or 5600?
To get out far enough would put you 1000 foot away and over the river and through the woods and then..well you would have no idea which tree. Plus all the trees are over 100 tall.
Call your local aerial photogrammetry guys and have them fly it with 1 ft contours. Tell them what your specific needs are. My guys are pretty compatible in that regard.
They can pick a ground elevation that fits, and a top of tree elevation that fits.
Aside from that, its pure math to figure it out. Shoot a distance to the base of the tree, turn a vertical angle to the top. Get out your HP48 and hope for the best.
Me, I'd have it flown. Likely more cost effective and potentially more accurate.
http://www.forestry-suppliers.com/search.asp?stext=inclinometer
http://www.forestry-suppliers.com/search.asp?stext=measure tree height
[flash width=560 height=315]//www.youtube.com/v/5H8s2zNRRv8?hl=en_US&version=3[/flash]
How tall do you think most of the trees are? I am guessing taller that 25 feet or you could use a level rod.
Could you buy some 10 foot or 20 foot pvc pipe and just keep adding on till you get to the top of the tree?
> We are working on a project where the client needs to know the heights of trees and/or the canopy. There are approx.. 25 trees we need to determine and they are in a heavily wooded and very hilly area. We cannot set up an instrument at any significant distance from the base of the tree and see the top which does not allow for us to use the old tangent Trig function. Any suggestions and or tools that may be useful? There has to be a forestry tool.
>
> A drone would be perfect, but..
How precise must your answer be? Keep in mind you are measuring a tree. The tippy top of the highest leaf today is different than that same leaf tomorrow. If all they need is plus or minus 4 or 5 feet, don't worry about setting up too close to accurately use trig functions. That distance will not be your accuracy limiting factor.
I often use a clinometer. Fits in a shirt pocket and does exactly what you need very quickly.
Larry P
How about something like this...
http://www.forestry-suppliers.com/product_pages/Products.asp?mi=22741&title=Hagl%F6f+HEC2+Electronic+Clinometers
Fill up a big balloon with helium and tie a 200' tape to it. Let the balloon do the work for you 😉
Yes you can, for the S/VX series at least.
Being Trimble it'll probably be silly money.
Maybe you can buy or borrow one with a different instrument?
Surprised no-ones suggested climbing up! Trained monkey?
Ok Dan, I'm one of those weirdo surveyors who actually did get his degree in Forestry (Mich Tech '77), but chose the surveying major for a career over managing forest crops. Go ahead and just knock me in the forehead.
I still have a Biltmore stick from those days somewhere in a shed. They do work. But you do need to perfect your pacing skills so you know how far you are from the tree, and also your arm length. It all goes together.
Like I said above, I'd have it flown and be done with it. Let them do the math.
The way they taught me in college to do it was to cut it down and pace it off. Works great.
(Just remember to account for the height of the stump.)
But......but......that would give you the length of the tree!!?? +o(
Use a clinometer and a rag tape to known how far away from the tree you are and sight the top of the tree. Solve using tan and repeat for the bottom of the tree add them together and you have your height of the tree.
I've done this before, and I used the Leica "Vector" / Aero Laser Rangefinder Binocular, the Vector 1500/ IV/ Aero/ 21 series to do it- (it now goes by the name of Vector- that division of Leica was bought by Vectronix- prior to that it was also called the Viper).
This will work if your area of interest with the trees leaves you enough room to sight to the top of the tree- if the canopy is too thick then you'll have to try aerial surveying/ lidar type methods.
For this you'll actually want to use the Aero model, which can sight up to 90deg vertically. (normal Leica Vectors are only good to +/- 30deg from horizontal.)
These binoculars have an inclinometer, compass, laser rangefinder, and 10x binocular- they have a choice of several settings for the range/distance/ height readout that will provide the following measurements: height, horizontal distance, slope distance and slope height, compass inclination, deviation/inclination from horizontal, and others). The rangefinders can also be integrated with a GPS, data collector or digital display to give GPS coordinates of the objects (trees, in this case)
-default distance reading is actual distance to the target (ie, laser straight-line distance to the object you're sighting).
For tree heights, under relatively flat terrain you'd use the default measurement mode, - the Vector can also be set to automatically calculate the height of the object assuming you're measuring from the same ground elevation as the base of the tree- (assuming the ground is flat, this would be the vertical height using slope distance and inclination)
But for hilly terrain, where you're taking the reading from a location that is not the same elevation as the base of the tree- use the 3rd setting:
- user can also take 2 readings, the 1st is to the bottom of the target, then the top of the target- readout will give the vertical distance between the 2. (this can also be done with horizontal targets).
I used the Aero model because it provides both straight-line distance (slope distance) and the vertical height simultaneously, at angles up to 90°, in the actual binocular eyepiece view as well as sending it and the GPS coordinates to a data collector.
If you want more info, contact me- I still have the Leica system to do this.
-Nathan
Leave it to a GBMT person to take 9 minutes to give you 35 seconds of information.
> Call your local aerial photogrammetry guys and have them fly it with 1 ft contours.
Rather expensive, for just 25 trees!
I've run into situations in which I couldn't see the tops from a distance because of the way the canopy rolled over, and couldn't see them from directly beneath due to foliage density. That required a lot of estimating, along with a note regarding accuracy.
The aerial solutions are nice, but pricey for just a few trees.
The best tool for the job is GPS -- climb to the top, tie the receiver to the end of a tape, lower the receiver until it touches the ground, read the tape. (Har har har.)
