Forest changes, which happened in the Shirakami mountains including the World Heritage Region (WHR), were analyzed in three periods between 1980 and 2000 using four Landsat images. The images were obtained in September 1980, August 1986, September 1992, and August 2000. Correlation matrices were computed for pairs of the red channel of two successive images in the order of obtained date using pixels where deciduous forests covered without any significant changes during the decades. A principal component analysis was applied to the pairs using the correlation matrices. Areas with biomass decrease, which showed logging and weeding, and areas with biomass increase, which showed vegetation growth, were identified by a thresholding of the resultant second principal component images. The area of annual biomass decrease after 1986 was about 60 % of the area before 1986 within 12 km from the border of WHR. The area of biomass decrease was almost same in every distance zones before 1986 regardless of the distance from the border. However, the area of biomass decrease in each zone within 3 km was 20 or 30% of the area in each zone further than 5 km after 1986. Thus, progress of controlling and diminishing logging of beech forests by the government officies, which had started as a logging ban in the Akaishi basin in 1986, appeared in the monitoring results.

View full abstract

Forest dynamics and regeneration were monitored for three beech stands with different forest structure in the core area of World Natural Heritage at Shirakami Mountains. The parameters showing forest structure (tree density, basal area, diameter distributions etc.), dynamic parameters (recruitment and mortality of trees) and those relating regeneration (seed production, seedling emergence etc.) were different among stands, suggesting their different histories of establishment. The relationships between stands along forest development process were estimated with the dynamic parameters obtained. The necessary accuracy and resolution for the monitoring are also discussed with the basis of experiencing the observation.

View full abstract

Structure, composition and their dynamics of plantations of Cryptomeria japonica (ca. 20 years) with colonizing native trees were investigated along Okuakaishi forest road in Shirakami mountainous district from 1998 to 2002. Stem density of Cryptomeria varied greatly among study plots ranging from 350 to 2300 no. ha^-1, and their basal area were also variable from 3.6 to 41.9 m²ha^-1. The plots with lower stem density and basal area did not show any tendency of improvement of stand conditions. Because the most important factor of mortality was damages by heavy snow, above spatial variation of stand growth was considered to result from spatial heterogeneity of snow depth during winter. Native broad-leaved trees colonized the plantations with basal area ranging from 0.0 to 15.4 m²ha^-1; their basal area was negatively correlated with the basal area of Cryptomeria japonica. Each plot was colonized by any one species of Pterocarya rhoifolia, Phellodendron amurense, Swida controversa, Betula maximowicziana, Magnolia obovata, etc., or more. Among them, water-demanding species such as Pterocarya, Phellodendron, Swida, etc. tended to be distributed in the plots with lower basal area of Cryptomeria. This should reflect the abundant water in early spring resulting from the greater snow depth. Some plots experienced significant compositional shift during the 5-years study. This suggested that the communities of native trees within the plantations were still under the unstable composition.

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract