Color aerial photography as a guide to foliar nutrient levels and site index in loblolly pine plantations

Color aerial photographs were obtained during the winter of 1979-80 of extensive areas of loblolly pine plantations in Franklin County, Alabama, and Wayne County, Tennessee. Three separate inter-preters using acetate overlays drew boundaries between color classes that could be detected within and among these plantations as seen on the aerial photographs. Interpreters identified three Munsell color classes (2.5 G 3/4, 2.5 6Y 5/4, and 2.5 GY 6/6) into which the range of loblolly pine crown colors detected on photographs were coded. Foliar nitrogen, site index, and basal area were positively correlated with increasing greenness in these Munsell color classes. This technique permitted evaluation of productivity (site index) and foliar nutrient status from color aerial photographs, enabling more efficient land classification and possibly more efficient use of fertilizers for increasing productivity.