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ARS Home » Research » Publications at this Location » Publication #109633
Title: LIGHT REFLECTANCE CHARACTERISTICS AND REMOTE SENSING OF TWO WEEDY PLANT SPECIES IN SOUTHEAST TEXAS

Author
item Everitt, James
item WILSON, RAY - TEXAS SOUTHERN UNIVERSITY
item YANG, CHENGHAI - TEXAS A&M EXP'T. STATION
item Escobar, David
item Davis, Michael

Submitted to: Intnl Conference On Geospatial Information In Agriculture And Forestry
Publication Type: Proceedings
Publication Acceptance Date: 1/31/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Invasive brush and weeds on grazing lands are a primary deterent to management of these areas. More accurate measurements of area infested canopy cover are essential to estimating the amount of damage or other ecological impact caused by invasive plant species. Remote sensing techniques offer rapid acquisition of data with generally short turn around time at costs lower than ground surveys. Chinese tallow and Macartney rose are two woody plant species that have become serious pests on southeast Texas grazing lands. Studies were conducted to determine the potential of using remote sensing techniques for detecting Chinese tallow and Macartney rose infestations in southeast Texas. Plant canopy reflectance measurements showed that Chinese tallow had higher visible red reflectance than other associated species during the fall when its foliage turned a red color prior to leaf drop. Macartney rose had higher near infrared reflectance than associated plant species during winter as a result of its evergreen foliage. Chinese tallow could be distinguished on conventional color aerial photography, whereas Macartney rose could be detected on color-infrared aerial photographs. These findings should be of interest to range managers, weed scientists and wildland ecologists.

Technical Abstract: The invasion and spread of noxious plants on grazing lands present serious problems to range mangers, weed scientists and wildland ecologists. Because these areas are often extensive and inaccessible, determining the extent of infestations or the botanical characteristics by ground surveys is difficult. Remote sensing techniques offer rapid acquisition of data with generally short turn around time at costs lower than ground surveys. Chinese tallow [Sapium sebiferum (L.) Roxb.] and Macartney rose (Rosa bracteata Wendl.) are two noxious woody plants that have become serious pests on southeast Texas grazing lands. Chinese tallow is a deciduous tree and Macartney rose is an evergreen shrub. Both species were introduced to the U.S. from China as ornamentals. Ground reflectance measurements and aerial photography [conventional color and color-infrared (CIR)] were conducted for this study. Reflectance measurements were made on Chinese tallow. Macartney rose and associated species were tested on several date across the year to determine if these noxious species were spectrally distinct in a specific phenological stage. Results indicate that Chinese tallow had higher visible red (0.63-0.69 um) reflectance than associated plant species during the fall when its foliage turned a red color prior to leaf drop. Conventional color and CIR aerial photographs obtained of Chinese tallow during this phenological stage showed that it could generally be distinguished on both films, but it was better delineated in the conventional color film. Macartney rose had higher near-infrared (NIR) (0.76-0.90 um) reflectance than associated plant species during the winter as a result of its evergreen foliage. Macartney rose could be readily detected in CIR aerial photographs obtained during February.