Forest canopy change caused by partial harvesting was examined using multitemporal Landsat Thematic Mapper imagery acquired in 1992 and 1997 in New Brunswick. Fifty stands that were originally typed as spruce, fir, pine, tolerant hardwood, intolerant hardwood and mixedwood were selected and sorted by year of partial harvesting treatment. Visual analysis of the colour composite imagery and brightness / greenness / wetness Tasseled Cap Transformation indices together with NDVI and principal components analysis showed a pattern of change over time in most areas of disturbance. For example, we found increased visible reflectance, decreased near infrared reflectance, and increased shortwave infrared reflectance in partially harvested stands. The change information was concentrated in one or two of the three principal components retained in the analysis, and in the wetness component of the TM Tasseled Cap transformation. Comparisons to undisturbed and clearcut areas were made to show the differences in reflectance and image transformations that were related to partial harvesting, clearcut, and undisturbed conditions. A classification hierarchy which included clearcuts and partial harvest stands was devised. Clearcuts were mapped with 71% accuracy between 1992 and 1997 using a per-pixel method. Individual stand classification, using the mean brightness/greenness/wetness values in 1992 and 1997 for each polygon in the GIS identified with a partial harvesting treatment, approached 71% accuracy for the complete sample of partial harvests. These results appear to be sufficient to justify further development of an optimal classification technique, and a software system to provide the automated update of the GIS forest inventory using remote sensing.

Forest management, classification