using infrared to follow air pollution effects

[Marilyn Howarth]

Would it be possible to compare serial infrared photos of trees that surround a hazardous waste site or hydraulic fracturing site and follow changes in the health of the foliage?

[Chris Fastie]

Marilyn,

Yes that could work very well. The deterioration of the tree health could be slow, so seasonal changes would complicate the interpretation. A powerful approach would be to photograph many trees near the source of toxins and many trees far from the source but in the same general location. The trees should be of the same species, of similar age and size, and growing in similar conditions (soil, ground water, exposure). Throughout the growing season, maybe twice per month, each tree should be photographed at the same time of day, on similar days (cloudy vs. sunny), in the same direction (e.g., the sun always over your right shoulder). A normal photo should also be taken of each tree at each time to demonstrate that the lighting, angle, and exposure are similar in all photos. Choosing scenes with little or no sky in the background will make exposure easier and make it easier to compare the photos of different trees, so it might be best to fill the frame with tree foliage (although then it becomes harder to demonstrate which tree is which). This is a lot of work, so it makes sense to start with good equipment, not experimental equipment.

It is best if there is no difference between the near and far trees when the monitoring begins. If there is a measurable difference between near and far trees in your first set of photos, you can't rule out that the trees differed for reasons other than proximity to the toxins.

Chris