Infinite Reflectance of Dead Compared with Live Vegetation1

Abstract

AbstractThe objective was to compare the infinite reflectance (R∞) of dead and live corn (Zea mays L.) leaves over the 0.5‐ to 2.5‐μm waveband to find a means of distinguishing live from dead vegetation for remote sensing purposes; previous studies have been concerned only with R∞ of live leaves. In this study, for both dead and live leaves, reflectance measurements were made on a single leaf seciton and for sections stacked two, three, four, five, six, seven, and eight at a time over a spectrophotometer's port. Live leaf R∞ was essentially attained by stacking two leaves for the 0.5‐ to 0.75μm waveband (chlorophyll absorption region), eight leaves for the 0.75‐ to 1.35‐μm waveband (near‐infrared region), and three leaves for the 1.35‐ to 2.5‐μm waveband (water absorption region). Dead leaf R∞ was reached over the entire 0.5‐ to 2.5‐μm waveband by stacking only two or three leaves. Thus aircraft and spacecraft reflectance measuring techniques probably cannot distinguish density differences of dead vegetation but they should distinguish density differences of live vegetation. Near‐infrared reflectance differences between dead and live vegetation also should be detectable with satellite multispectral scanner data.