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:

Continuous Creation

A religious philosopher living in the 1200s had an amazing idea: that God was continuously creating the world. For example, every time you looked outside your window at a tree, God was actively and continuously creating that tree. The name of the philosopher was Thomas Aquinas. During college, I remember how in my ethics class, the professor spoke passionately about this idea of Aquinas. It’s a beautiful idea. The notion that we are all held up in this act of continuous creation. Interestingly, it might not be too far off from what science tells us, if you put aside the question about the existence of God for a moment, and talk about existence itself. In physics, Einstein’s famous equation

E=mc^{2}

tells us that mass and energy are connected. In this podcast, at 17 minutes and 10 seconds, they are discussing this notion of the effort or energy that goes into anything existing, even for a moment, which seems like a parallel to what Aquinas what describing, at least taken figuratively. Check it out!

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.