Tree shape and volume measurement by light interception and aerial photogrammetry

Site specific information on the foliage shape and size of orchard trees is a major factor in determining spray dosage for plant protection and crop c oefficients for irrigation scheduling. A computerized map of each individua l tree in the orchard is required to adjust irrigation emitters and variabl e spray volumes. In a feasibility study conducted at the Matityahu Experime ntal Farm in 1998, aerial photogrammetry was used to facilitate fast and af fordable tree shape and volume mapping. Light interception cross-sections a nd gap frequency analysis was used for ground measurements of trees. Panchr omatic, 1:4000 scale, 100 lines/mm resolution stereoscopic aerials sewed fo r analog photogrammetric processing. Tree contours and row cross-sectional area compared well between aerial- and ground-based measurements. Resulting tree volume maps seems to be sufficient for current applications in plant protection and irrigation scheduling. Further development of the method usi ng multiple wavelength measurements will probably be needed in order to obt ain estimates of foliage density and LAI.