This summer has been somewhat hectic for me. I am glad to carve out enough time to continue this series with an interesting find. I have an extremely (at least I think) heavy teaching load usually consisting of three lectures and two labs each semester. For my upper level courses I try to take students in the field as much as possible. While reading a very interesting paper a few months back by Sara Kuebbing I had an epiphany. She used a fish eye lens and free downloadable software from Cary Institute of Ecosystem Studies found here developed by Gordon Frazer and Charles Canham……….I know many of the readers are thinking wow this guy is behind the times, but all I could think was BINGO!!!!
Now here is where the CHEAP part comes in. In my haste to get my field courses up and running I purchased items that I had used as a student (antiquated I know). Some of my first purchases were spherical densiometers to allow my students to somewhat accurately determine canopy closure. Teaching the students how to accurately read the densiometer proved, well putting it nicely, difficult. And not to mention these little gizmos are relatively expensive >$100 each and I purchased 7.
At this point I was looking for an alternative after apparently wasting money. After examining the long list of light meters from companies like LiCor etc. I knew that there was no way I could sell that to my dean, academic VP or my dept. chair.
ALAS, the FISHEYE lens. There are a multitude of lenses from different manufacturers for specific camera models. I use a canon dslr and found this relatively inexpensive lens from amazon for < $250. It works great with my camera and although the major complaint is that it is a fully manual lens I prefer this. In thick canopied forests I prefer to alter the iso and aperature myself. The booklet that comes with the lens is good for getting initiated into fisheye photography especially for focal length settings. Below is one image that was taken in late May.
The software GLA from Cary is easy to use and the only thing I would recommend is to always orient the top of the image northward for easier calibration.
Happy Canopy Measuring.