Category: Work

Measuring the Height of Trees with a Clinometer/Laser Rangefinder: Sine works better than Tangent

When I first got interested in measuring the heights of trees, after reading a wonderful book called The Wild Trees: A Story of Passion and Daring by Richard Preston, I thought that finding the tangent was the best way to calculate the height of a tree. After all, I didn’t have a way to measure the hypotenuse — the distance from me to the top of the crown. However, a laser rangefinder let’s you calculate that distance, which in turn makes it much easier to get an accurate reading for the height of a tree. Thanks to the Eastern Native Tree Society (ENTS) for posting a helpful article about this.

Here’s a link to the article.

And a file download:

    Tree_Measuring_Guidelines-revised1Download
    Photo by Andry Z. Rakotomalala

    The Arrow and the Song

    BY HENRY WADSWORTH LONGFELLOW

    I shot an arrow into the air, 
    It fell to earth, I knew not where; 
    For, so swiftly it flew, the sight 
    Could not follow it in its flight. 

    I breathed a song into the air, 
    It fell to earth, I knew not where; 
    For who has sight so keen and strong, 
    That it can follow the flight of song? 

    Long, long afterward, in an oak 
    I found the arrow, still unbroke; 
    And the song, from beginning to end, 
    I found again in the heart of a friend.