Large-scale aerial photo comparison for detecting pine dieback

Summary

Large scale 70 mm colour and black and white aerial photographs were compared with ground-observations for interpreting dieback in drought-stressed pine (Pinus radiata). Eighty percent of classifications on black and white agreed with ground assessments, compared with 78 percent for colour. Analysis of photo omissions and additions however, showed colour photos to be superior because they portrayed damage not detected on black and white photographs. Colour photographs also gave better information on dying and dead foliage in upper crowns in comparison with ground-observations.