Submitted to: Workshop Color Aerial Photography & Videography in Plant Science Proceeding
Publication Type: Proceedings
Publication Acceptance Date: October 15, 2005
Publication Date: March 15, 2006
Citation: Everitt, J.H., Yang, C., Johnson, H., Davis, M.R. 2006. Using color-infrared aerial photography to distinguish Ashe juniper. In: Proceedings of the 20th Biennial Workshop on Aerial Photography, Videography, and High Resolution Digital Imagery for Resource Assessment, Bethesda, Maryland. 2006 CDROM. Interpretive Summary: The invasion and spread of undesirable plant species on rangelands present serious problems to range managers and ranchers. Ashe juniper is an evergreen shrub or small tree that invades rangelands in central and west Texas. A study was conducted to determine the light reflectance characteristics of ashe juniper and evaluate the potential of using color-infrared aerial photography for distinguishing and mapping this troublesome woody plant species. Ashe juniper had distict reflectance characteristics during spring and summer that facilitated its detection on color-infrared aerial photographs. Computer analysis of color-infrared photographs indicated that ashe juniper infestations could be quantified. These results should be of interest to rangeland resource managers who are interested in controlling this undesirable species and monitoring its distribution over large and inaccessible rangeland areas.
Technical Abstract: Ashe juniper (Juniperus ashei Buchholz) is a noxious shrub or small tree that invades rangelands in central and western Texas. A study was conducted in central Texas to determine the potential of using color-infrared aerial photography to distinguish ashe juniper infestations. Field reflectance measurements indicated that ashe juniper had lower near-infrared reflectance than other associated woody plant species and lower visible reflectance than mixed herbaceous species in spring and summer. Reflectance measurements obtained in fall and winter showed that ashe juniper could not be distinguished from one or more associated woody species in either the visible or near-infrared spectral regions. Ashe juniper could be distinguished on color-infrared aerial photographs acquired in March, April, June, and August where it had a distinct dark reddish-brown tonal response. Computer analysis of photographs showed that ashe juniper infestations could be quantified. Accuracy assessments performed on the classified photographic images had producer’s and user’s accuracies that ranged from 83% to 100%.