The University of Arizona

A proposed method for determining shrub utilization using (LA/LS) imagery.

M.C. Quilter, V.J. Anderson

Abstract


Utilization of plant above ground biomass has continued to be a critical yet difficult assessment in rangeland monitoring. Shrub size and woody structure further compound the measurement of shrub biomass utilization. This study was designed to determine the potential utility of low altitude/large scale (LA/LS) imagery in assessing shrub utilization. A near monoculture of Ceriotoides lanata (Pursh) J.T. Howell (winterfat) located in the western desert shrubland of Utah was used to evaluate this technique. Four, 3.1 by 3.1 m plots were identified and the shrubs within the plots were defoliated by hand-picking at about 10% intervals with imagery of the plots obtained between pickings. Imagery was obtained using a radio controlled airplane (drone) fitted with a 35 mm camera. Images were evaluated using image processing software and the resulting reflectance data correlated with defoliation percentages (weight basis) for each plot. Reflectance data from images correlated highly with defoliation percentages (r2 > 0.9). This technique of using LA/LS imagery shows promise for a quick and accurate tool in assessing utilization of shrubs.

DOI:10.2458/azu_jrm_v54i4_quilter


Keywords


aerial photography;reflectance;methodology;leaves;evaluation;image analysis;remote sensing;shrubs;defoliation;Utah;browsing;grazing

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