Abstract

Polarized visible light is an indicator of scene roughness; smooth surfaces polarizing visible light to a greater extent than rough surfaces. On the assumption that canopy roughness is a function of vegetation amount, the relationship between polarized visible light and vegetation amount was investigated. Twelve aerial survey flights taking polarized visible light photography were made during an 18 month study. At the same time, either percent vegetation cover or dry green biomass (by harvest), were recorded for each of four vegetation types: mature carr, young carr, scrub, and pasture. There was a linear relationship between polarized visible light and vegetation amount, with an average correlation of r=0.63 (significant at the 5% level). In the winter, the sites had a variable canopy and percent polarization. In the summer, when canopies were complete and undisturbed, the ability to estimate vegetation amount was maximized, but the difference between sites minimized.