Aerial photograph use in developing and testing a geographic data base for pecan (Carya illinoensis (Wangenh.)
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Date
1980
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Abstract
A geographically referenced data base of the native pecan in portions of Texas was compiled from color infrared aerial photographs at a scale of 1/10,000. The Universal Transverse Mercator grid system was employed to reference the photographs to U.S. Geological Survey Quadrangle maps. Using the case example approach, this research demonstrated the utility of sound sampling procedures, in conjunction with a reliable data base. Sampling procedures were employed to draw the minimum number of samples necessary from three strata of pecan to render reliable estimates of walnut caterpillar defoliation. The selected samples were evaluated in detail on the photography and an estimate of percent defoliation was made. The sampling for defoliation was checked by a complete enumeration. The sampling procedures produced an estimate of degree of defoliation with a standard of 1.06%. The identical sampling procedures were employed to estimate the quantity of pecan timber that could be removed from overstocked stands. A regression model was used to determine the timber volume from photo graphic measurements of stems per hectare and percent crown closure, and field estimates of volume. The sampling procedures and computer software are sufficiently versatile to allow for future use of this system.
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Typescript (photocopy).
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Major forestry