Canopy Light Reflectance and Remote Sensing of Shin Oak (<i>Quercus havardii</i>) and Associated Vegetation

Abstract

Shin oak is a deciduous shrub that forms dense stands of brush on sandy soils in rangeland areas of the Rolling and High Plains of Texas. Plant canopy reflectance measurements made on shin oak showed that it had both low visible (0.63- to 0.69-μm waveband) and nearinfrared (0.76- to 0.90-μm waveband) reflectance values, a characteristic generally not shared by associated plant species or mixtures of species. The low reflectance values of shin oak caused it to have dark-red, reddish-brown, or brown image tones on color-infrared photographic, videographic, and SPOT satellite images that made it distinguishable from associated vegetation and other land use features. The optimum time to remotely distinguish this noxious shrub is during the mature phenological stage from June to September. Computer-based image analyses of video and satellite images showed that shin oak populations could be quantified. This technique can permit “percent land area” estimates of shin oak on rangelands. The aerial imagery is useful for detecting shin oak on smaller rangeland areas, whereas the satellite imagery is applicable in mapping large areas of shin oak distribution.