DETECTION OF YELLOW HAWKWEED (HIERACIUM PRATENSE) WITH HIGH-RESOLUTION MULTISPECTRAL DIGITAL IMAGERY

Yellow hawkweed infests permanent upland pastures and forest meadows i n northern Idaho. Conventional surveys to determine infestations of th is weed are not practical. A charge coupled device with spectral filte rs mounted in an airplane was used to obtain digital images (1 m resol ution) of flowering yellow hawkweed. Supervised classification of the digital images predicted more area infested by yellow hawkweed than di d unsupervised classification. Where yellow hawkweed was the dominant ground cover species, infestations were detectable with high accuracy from digital images. Moderate yellow hawkweed infestation detection wa s unreliable, and areas having less than 20% yellow hawkweed cover wer e not detected.