DBH String- a project for retired throwline


King of Splices
Mar 30, 2005
Snowless California
I was in the mountains yesterday checking out trees. I wanted to know the DBH, but had to tape on me. I can guess close enough (I think) but I wanted exacter numbers.

Rather than hauling around a measuring tape, I came up with this:


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I took a 13' piece of the NER throwline (zing it would work great, too). I spliced an eye one one end. This is the "zero-eye" mark. Then I tied an over hand knot 3.14159 down the rope. This comes to 37 11/16ths of an inch.

I went down another 37+ inches and tied a double overhand. Went again tying a triple overhand, and one more time, tying a quadruple overhand knot.

So now I could walk up to a tree, feed the tail end through the zero-eye, then pull tight. I find the last knot. If the first overhand knot is even with the zero-eye, then the tree is exactly 1' DBH.

If it's somewhere between 2 knots, you have to estimate.

I took it a step further. I put 5 marks (tiny whippings) between each knot. They are color coded- red, orange, yellow, green, blue. The colors of the rainbow. There is one every 2" x pi. This comes to 6 1/4". Now, I can look through and estimate DBH to the nearest 2"!

In the picture above, that Liquidambar styraciflua has the orange mark at the zero-eye. That tree is about 1' 4.5" DBH.

It seriously took me about 2 hours to make the whole thing with whippings and everything, but I have a neat little tool that will take the guess work out of measuring trees


note- I wanted a lighter weight option than carrying a measuring tape. Back-country hiking is best when you have less to carry!
hm, cool for recyclers but as MB said, I have a D-tape in my truck, and a 50' reeltape that I can do the math on if pressed to measure DBH the old fashioned way.