How to calculate tree height?

[LANNY]

I need to drop a 18" or so oak near the road. I can only guess the height with the pencil trick. Still close, too close to guess. I really don't want to start on a ladder, Can anyone educate me on a precise way to measure tree height ? Any help would be appreciated. Road is not traveled much, just goes around our farm, two houses on it, but I hate to hit it....Lanny

 

[habanero]

You can do it by using a little trigonometry (standing a known distance away, find the angle to the top, then calculate the height of the tree), but that's not always the simplest way.

A quick and dirty method I've used is to strap a board of known length to the tree, then take a picture that encompasses the whole tree from a ways away. Print out the picture on paper, measure the length of the board in the picture as well as the length of the tree. Since you know the length of the board in real life, you can find the ratio of the real length to the picture length, then apply that to the picture length of the tree and get the "real" height. This method has some inaccuracies, but generally should get you within a few feet. The longer the board is, the less error, and generally the further you are from the tree the less error there is (compensates better for lens distortion).

 

[rdbrumfield]

Take a stick, or anything long enough to reach from the valley between your thumb and index finger, lie it on your arm to reach your eye. Pivot the stick up to verticle, be sure that the base of the stick is level with your eye and that you are pretty much level with the base of the tree. Look at the top of the stick, if you see tree at the top of the stick, back up until the top of the stick and the top of the tree line up. Now add the distance from your eye to the ground, for instance 5'5" from where you stand behind you. From that point to the base of the tree is how tall the tree is. If you do this correctly you can be within inches.

 

[gink595]

You can do it by using a little trigonometry (standing a known distance away, find the angle to the top, then calculate the height of the tree), but that's not always the simplest way.

I can see that working, get a compass with an inclinometer in it and stand "x" amount of feet away and point the inclinometer until you reach the top of the tree and record the amount of degree's. Heres an example I drew fro ya.

 

[habanero]

I can see that working, get a compass with an inclinometer in it and stand "x" amount of feet away and point the inclinometer until you reach the top of the tree and record the amount of degree's. Heres an example I drew fro ya.

That's the way I was taught to do it in an environmental science class I took once upon a time (don't remember why they had us out measuring tree heights). The trouble is having an accurate way to measure the angle-unless you already have something to do that. With an accurate angle measure, though, everything else is pretty easy.

 

[gink595]

That's the way I was taught to do it in an environmental science class I took once upon a time (don't remember why they had us out measuring tree heights). The trouble is having an accurate way to measure the angle-unless you already have something to do that. With an accurate angle measure, though, everything else is pretty easy.

I wonder if one of those distance finders for hunters would work, I know they have them now where they will triangulate the yardage. I got to thinking afterwards, If you could get an inclinometer and walk out until you find 45* on it, then you could measure back the dist to the tree and that should be close to the height

 

[LANNY]

With the 45 degrees in mind , could you use say, a speed square with some modification for sighting to get the distance to the tree, and add height to you eye level? Good info guys, I figured it was a math solution. Thanks...Lanny

 

[bigden]

clinometer

i use the optical reading clinometer from suunto the pm-5
it is set up to be 82 feet from the base of the tree.
you stand 82 feet away and look through the pm-5 and look at the height's point on the tree and it gives you your height.the times that i have used the thing it seams to be pretty close. i have switched to the laser range finder because it works better for the crane because most of the time with the crane it is if i can reach the top. with the 70 ton and 127 full power boom i get the big ones all the time so guess work is not an option.but the range finder will not give you the length of the tree. the clinometer has been with in a 5 foot plus or minus.also the pm-5 is around 80 bucks

 

[AKKAMAAN]

Camera for measuring tree height

I need to drop a 18" or so oak near the road. I can only guess the height with the pencil trick. Still close, too close to guess. I really don't want to start on a ladder, Can anyone educate me on a precise way to measure tree height ? Any help would be appreciated. Road is not traveled much, just goes around our farm, two houses on it, but I hate to hit it....Lanny

Lay out a marking on a Known distans (ex 25 ft from the tree), preferably close to the direction you will fell it. Try to make the distans close to the height of the tree. Imagine a line between the tree and the marker, and back of square to that tree and the line, like 3-5 times the distans of that line. Make sure the whole tree, and the ground marker gets into the picture.
Take your digital camera and take a picture....print it out and ON THE PRINTOUT, using a ruler or tape, measure the distans on the ground A, and the height of the tree B.
ex
A=1.50"
B=1.25"
K=25'

Real height=KxB/A=25x1.25/1.50=20.83'

REMEMBER THAT TREE CAN MOVE FORWARD A FEW FEET WHEN LANDING!
CUT THE TREE 5ft UP IF IT IS 5ft TOO TALL!

 

[mimilkman1]

Take a stick, or anything long enough to reach from the valley between your thumb and index finger, lie it on your arm to reach your eye. Pivot the stick up to verticle, be sure that the base of the stick is level with your eye and that you are pretty much level with the base of the tree. Look at the top of the stick, if you see tree at the top of the stick, back up until the top of the stick and the top of the tree line up. Now add the distance from your eye to the ground, for instance 5'5" from where you stand behind you. From that point to the base of the tree is how tall the tree is. If you do this correctly you can be within inches.

This is similar to the way I was taught in forestry class in high school but we used Biltmore sticks. We used those to figure how many logs were in a tree too. I forgot how to use the d@*n thing though. Also don't know where one would find one nowadays.

Kyle

 

[ericjeeper]

The way I see it..

It really does not matter how tall it stands.. You need to know how long it will lay. LOL
The swanson speed square and a level will put you spot on. add the distance from your eyeball to where you stand.
Granted you need to do this in a level plain from the base of the tree.

 

[Ske-bum]

That's the way I was taught to do it in an environmental science class I took once upon a time (don't remember why they had us out measuring tree heights). The trouble is having an accurate way to measure the angle-unless you already have something to do that. With an accurate angle measure, though, everything else is pretty easy.

The problem with this is if your angle measurment is off you are going to get a bad number. It is going to go south in a hurry. Also using sin and co-sin with degrees the math can get ugly.

I would use the perportion method that habenaro suggested. Less chance for error and easier math.

 

[gink595]

The problem with this is if your angle measurment is off you are going to get a bad number. It is going to go south in a hurry. Also using sin and co-sin with degrees the math can get ugly.

I would use the perportion method that habenaro suggested. Less chance for error and easier math.

Yes if you don't understand the math and to be honest I really don't remember all the formulas anymore and I do this stuff everyday but I have calculators setup to avoid doing it longhand but Right triangles are fairly easy to figure, you can also find calculators online where you just plug in the numbers where they go and wham, instant answer. If the OP wants to give me the Angle and the distance I will figure it for him or e-mail him a excel sheet that will auto calc it.

http://www.csgnetwork.com/righttricalc.html

 

[ray benson]

Ekka made a video of this problem.
http://www.arboristsite.com/showthread.php?t=35362&highlight=tree+height

 

[berry5]

a guy a work uses a balloon and some small thread, lets the balloon go holds on to the thread, stops it at the top of the tree marks the thread, pulls the balloon down marks it off on the ground. works pretty good

 

[BuddhaKat]

I just make sure the truck is far enough away and screw the rest. :greenchainsaw:

 

[Ske-bum]

Yes if you don't understand the math and to be honest I really don't remember all the formulas anymore and I do this stuff everyday but I have calculators setup to avoid doing it longhand but Right triangles are fairly easy to figure, you can also find calculators online where you just plug in the numbers where they go and wham, instant answer. If the OP wants to give me the Angle and the distance I will figure it for him or e-mail him a excel sheet that will auto calc it.

http://www.csgnetwork.com/righttricalc.html

Yeah, having a nice HP programable calculator or something along those lines is the way to go. Less room for error and easier on the brain cells. Sounds like he will get his answer from someone.

 

[projectsho89]

A speed square, a small bubble level, a straight eye, and the ability to count a measured pace (or a long measuring tape) will get you close enough.

You figure out how to do it from that list....

Steve

 

[Raymond]

:computer: Man just drop the thing and get-r-done.
So what if it goes in the road.

 

[Raymond]

a guy a work uses a balloon and some small thread, lets the balloon go holds on to the thread, stops it at the top of the tree marks the thread, pulls the balloon down marks it off on the ground. works pretty good

You just thought of that didn't you?
Don't lie... oh we can tell.