Forestcrowns: a Software Tool for Analyzing Ground-based Digital Photographs of Forest Canopies

—Canopy coverage is a key variable used to characterize forest structure. In addition, the light transmitted through the canopy is an important ecological indicator of plant and animal habitat and understory climate conditions. A common groundbased method used to document canopy coverage is to take digital photographs from below the canopy. To assist with analyzing below-canopy photographs, the U.S. Forest Service Southern Research Station has developed a computer software tool called ForestCrowns. ForestCrowns calculates canopy transparency (or light transmittance) for digital images taken with standard or fi sheye (hemispherical) camera lenses. Specifi c areas of the photograph can also be targeted to obtain transparency estimates of individual tree crowns. Since images and assessment results can be saved within the program, ForestCrowns can also be used with forest health monitoring programs to detect changes over time in canopy structure due to storm, insect, or disease damage.