measuring tree height

Measuring tree height is a fun activity for kids. It's amazing how rewarding it is to show them how to do this easy science project. Here's how.

All you need is a broomstick and a tape measure. Even a short tape can be used. The tree and area around it on at least one side must be visible and accessible. It should be level for best accuracy.

Get far enough away from the tree so that the entire tree is easily visible. This distance is not critical.

Take the broom and hold it vertical at arms length. Place the tip of the handle so it is seen to be at the tip of the treetop.

Slide your hand along the length of the handle until it is lined up with the base of the tree at ground level. Now confirm that the exposed broom handle above your hand is the same length as the view of the entire tree height.

Take a firm grip and turn the handle sideways. Your hand should still be at the center of the base of the tree. Tell someone to walk over and stand where the tip of the broom handle is seen.

Now, simply take the tape and measure from that person to the tree trunk. Voila! That is the height of the tree.

Kindergartners can do this. You should be able to, also. Enjoy!

Ox
 
This is the 2nd time I've read this description for measuring tree height. I need this bit of detail added to the description for my own peace of mind. The 2nd person is located at the tree. The broom handle is rotated 90° sideways, or horizontal to the ground. Starting at the base of the tree, the 2nd person then walks perpendicular to the person holding the broom, or along the horizontal line made by person 1. The 2nd person stops walking when person 1 tells them they have sighted them at the end of the handle like person 1 initially sighted the top of the tree.

There are many different descriptions for measuring tree height on the web.

Joe
 
Why not get a clinometer? (sp?) I got one from my dad from his years with the forest service. I think the one from between your legs might just be more fun though!
 
The correct spelling is clinometer. The source for the spelling is my most current Forestry Suppliers catalog.

Actually, I shared the link which started this thread
because I imagined a bunch of tree guys measuring the height of trees in various public places with this method. Could you imagine watching any of a number of salesmen, treeguys, or academicians measuring the height of trees with the indian method? What kind of picture do you get? That's why I posted it.

Ox's method seems to be a variation of what we know as the stick trick. It took a while for me to figure out the horizontal part.

If one searches the web, there are many other ways for figuring tree height. I actually found a method for figuring crown spread and biomass ratios. Tree measuring can be simple or intense. It depends on what one wants to know.

Joe
 
I have 3 clinometers, two are English and a backup one is metric. This is a super accurate method of estimating tree height. The Ranger compass, manufactured by Silva, also has a clino pendulum on it. [image]http://images.google.com/images?q=tbn:zm0R4a3bTF4J:arch.ced.berkeley.edu/kap/1998_images/Background/suunto.jpg[/image]
I got them at various swap meets, for about $25 apiece. I wonder what a Suunto goes for now? This is a very durable instrument.

To start with I plug a tape into the trunk and step away from the tree 100 feet. I step back 66 feet with the metric clinometer. Both top and bottom of the tree must be visible from the same spot. For trees up to 200 feet tall, step back 200 feet. For best accuracy the distance should be measured from the center of the trunk, but this deviation is not enough for me to worry about.

Look through the clinometer with both eyes open. Sight at the base of the tree with one eye, and at the gauge inside the clino with the other eye. Tilt the clino slightly until the base of the tree lines up with the a marking on the gauge. This mark should be about -5, if you are on level ground. This number will be added to the final measurement.

Since eye level is 5 or 6 feet above the ground, I sometimes sit down to take the sighting through the eyepiece. Alternately, start with your sighting target at a place on the trunk that is at eye level. Otherwise, add 5 feet from your final readout.

Now you are ready to take a bead on the top of the tree. Tilt your head back and find the top with one eye. With roundheaded trees, this can take a bit of imagination & experience.

With the other eye, look into the clino and view the gauge as it pendulums and comes to a stop. Visually superimpose the dial over the treetop to get your readout. This takes about five seconds to stabilize.

Since the dial is graduated with markings in feet, hold very still while you are taking the reading. All that is left is to adjust for how far from horizontal the sighting point was. Bingo! You're done.

It is a good idea to verify the height of a few trees with another method, such as climbing them, then rapelling with a rope of known length. Compare your measurement of these benchmarks to confirm proper operation of the clinometer.

The Pythagorean Theorum is a mathematical formula that prooves this measurement.

A squared plus B squared equals C squared is one way to state it.

Another is "The square of the hypoteneus is equal to the sums of the squares of the 2 sides (the hypoteneus is the long side of a right triangle).

Now that I've muddled it up, lets go climb some trees!
 
Sometimes I'll measure tree or trunk height with this little digital do-dad from HAGLOFSWEDEN.com. It's real easy. It has one button to press at 3 different times.
First, set distance from tree. Then hit once for your angle to the base(or where your cutting it). Hit again to set the angle. It will tell you +or- whatever # depending on slope and such. Then sight up tree to point desired, hit button again, hold for 2 seconds then boom, your number. It has a +,- of .2 degrees and +,- of 2 feet or less. Cool little toy. If trying the old HERO/AS*H*LE cut, you might want to get a better measurement, though this does work pretty well.
Later
 
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