hemispherical canopy photographs

Uses and limitations of hemispherical photography for estimating forest light environments

We compare hemispherical (fisheye) photography and direct measurement using dataloggers for quantifying light intensity (photon flux density) in a New Zealand forest remnant. The hemispherical method was generally accurate, and faster than using dataloggers, but deviated from measured light intensity at low light levels (<20% of full sunlight). For deeply shaded sites, diazo-paper chemical light meters may be more suitable.