Light spectra and remote sensing of Ashe juniper and associated vegetation on Texas rangelands. Everitt, James^*,1, Yang, Chenghai¹, Johnson, Hyram, Alaniz, Mario¹, Davis, Rene¹, ¹ USDA-ARS, Weslaco, Texas, USA

ABSTRACT- Ashe juniper (Juniperus ashei Buchholz) is a noxious shrub or small tree that invades rangelands in central and western Texas. It reaches its greatest proportions in the Edwards plateau of central Texas. A study is being conducted near Belton in central Texas to determine the potential of using remote sensing technology to distinguish ashe juniper infestations. Field reflectance measurements indicate that ashe juniper has lower near-infrared reflectance than other associated plant species in spring and summer. Ashe juniper could be distinguished on color-infrared (CIR) aerial photographs acquired in April, May, and June where it had a distinct dark reddish-brown tonal response. Aerial photos and reflectance measurements obtained in February showed that ashe juniper could not be distinguished from live oak (Quercus virginiana Mill.). Aerial photos are currently being subjected to image analysis techniques. Accuracy assessments will be conducted to verify the image analysis results. Preliminary findings indicate that remote sensing may be a useful tool for distinguishing ashe juniper over large and inaccessible rangeland areas.

KEY WORDS: remote sensing, ashe juniper, light reflectance, color-infrared photography