Tree trigonometry

Markus Eichhorn shows off a clever trick for estimating the height of trees! Markus is a tree expert and lecturer in ecology at the University of Nottingham. More about him and Nottingham scientists at http://www.test-tube.org.uk/

Category:

Science & Technology

Tags:

• trees
• height
• trigonometry

[hasimademselin]

@mdiem

thanks man, i understand how this works now... cos the stick is the same length as your arm, its as if the triangle with your arm and the stick (the smaller triangle) would be the same (scale wise) as the tree height and the distance on the floor...

[hasimademselin]

@mdiem

thanks man, i understand how this works now...

[mdiem]

@hasimademselin

What bxs0099 said: Similar triangles. Base 1 is to base 2 as height 1 is to height 2, and base 1 equals height 1.

(base 1 = length of stick, base 2 = height of tree, height 1 = distance from eyes to stick, height 2 = distance from eyes to tree)

Draw a picture to help visualize.

[mdiem]

I remember learning this in Boy Scouts. Also, how to measure the width of a river using your hat. ;-)

[bxs0099]

i would imagine similarity of triangles has something to do with it.... hencematching up the length of the stick with the height of the tree from a suitably chosen distance d from the tree

[hasimademselin]

I've tried this and it works, but why does it work? Anyone?

[redishdog]

ahhh... it's a right triangle, right,,,, ... lets see a level, a tape, perhaps a protactor... ahh, still watching..... slightly more accuate, though.. distance and angles should give slightly more accurate results than the "stick" method.. edited to add that if it's not level ground, you can still make two right triangles and hell trig works like a champ.... level ground and straight trees (preferably standing straight) work easier

[YumClock]

Clever use of isosceles triangles. Genius to think of it in such a practical way.

[southoreast]

@rephaim22 That's why it's called an estimate,

[NikAbbot]

Neat trick, I like it. Thanks.