Abstract
Usefulness of the spectral age, which was estimated using Landsat TM imagery based onsuccessional spectral change curves of spruce (Picea jezoensis Carr., Picea glehnii Mast.) stands in Tomakomai, Hokkaido, Japan, was evaluated by analysing stand condition and annual changes. Bigger and smaller spectral age than stand age showed denser spruce dominant stands and sparser spruce stands with broadleaved trees much more than standard stands of the successional spectral change curves respectively. Thus the spectral age showed standard spruce stand condition in each stand age rather than the stand age itself. The difference of spectral age images, which were estimated using winter and summer TM images in 1985, showed differences of spruce crown coverage in stands well. Removing of broadleaved trees or thinning of spruce trees were detected, when the spectral age images of two summer TM images in 1985 and 1993 were compared. Since the spectral age changes linearly against time coursing in any growth stages, it would be an excellent index, with which we can intuitively understand changes in stands during their growth.
