Relationship between Landsat TM and SPOT vegetation indices and cumulative spruce budworm defoliation

摘要

Thirty-five stands of mature, closed canopy black spruce (Picea mariana), white spruce {Picea glauca) and balsam fir (Abies balsamea) in Prince Albert National Park, Saskatchewan, were assessed for cumulative defoliation caused by eastern spruce budworm (Choristoneura fumiferana). Multitemporal Landsat 5 TM images (15 June 1992 and 18 July 2004) and a single-date SPOT 4 HRVIR (high resolution visible and infrared) image (19 August 2004) were obtained over these stands. Correlation analysis suggested that the strength of the relationship between the defoliation and various vegetation indices was generally moderate. The SPOT HRVIR indices were more highly correlated to cumulative defoliation than the Landsat indices, and the multitemporal Landsat TM index outperformed the single-date Landsat TM index. These results may help in the design of defoliation assessment procedures that integrate satellite remotely-sensed data and aerial sketch mapping techniques.