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ARS Home » Research » Publications at this Location » Publication #186500
Title: CANOPY SPECTRA AND REMOTE SENSING OF ASHE JUNIPER AND ASSOCIATED VEGETATION

Author
item Everitt, James
item Yang, Chenghai
item JOHNSON, HYRUM - 6204-05-15

Submitted to: Environmental Monitoring and Assessment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2006
Publication Date: 10/28/2006
Citation: Everitt, J.H., Yang, C., Johnson, H.B. 2007. Canopy spectra and remote sensing of Ashe juniper and associated vegetation. Environmental Monitoring and Assessment. 130:403-413.

Interpretive Summary: Invasive species are an extremely big problem in the United States and cost its citizens over $130 billion annually. Ashe juniper is an invasive, evergreen shrub or small tree that invades rangelands in central and west Texas where it displaces other plant species and uses excessive amounts of water. A study was conducted in central Texas to determine the potential of using remote sensing techniques to distinguish Ashe juniper infestations. Ashe juniper had lower near-infrared reflectance than other woody plant species and lower visible reflectance than mixed herbaceous species in spring and summer. Ashe juniper could be distinguished on aerial color-infrared photography acquired in spring and summer and on QuickBird false color satellite imagery obtained in summer. Accuracy assessments performed on computer classified maps of photographic and satellite images showed that Ashe juniper had producer’s and user’s accuracies that ranged from 87% to 100%. These results should be of interest to rangeland resource managers.

Technical Abstract: A study was conducted in central Texas to determine the potential of using remote sensing technology to distinguish Ashe juniper (Juniperus ashei Buchholz) infestations on rangelands. Plant canopy reflectance measurements showed 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. Ashe juniper could be distinguished on color-infrared aerial photographs acquired in March, April, June, and August and on QuickBird false color satellite imagery obtained in June, where it had a distinct dark reddish-brown tonal response. Unsupervised classification techniques were used to classify aerial photographic and satellite imagery of study sites. An accuracy assessment performed on a computer classified map of a photographic image showed that Ashe juniper had producer’s and user’s accuracies of 100% and 92.9%, respectively, whereas an accuracy assessment performed on a classified map of a satellite image of the same site showed that Ashe juniper had producer’s and user’s accuracies of 94.1% and 88.1%, respectively. Accuracy assessments performed on classified maps of satellite images of two additional study sites showed that Ashe juniper had producer’s and user’s accuracies that ranged from 87.1% to 96.4%. These results indicate that both color-infrared photography and false color satellite imagery can be used successfully for distinguishing Ashe juniper infestations.