Vegetation patterns and their dependency on site conditions in the pre‐industrial landscape of north‐eastern Japan

We reconstructed the vegetational landscape of the pre‐industrial era (the beginning of the twentieth century) in north‐eastern Japan, and estimated the distribution patterns of traditional land‐uses, as suggested from the vegetation. We found significant correspondence between the spatial patterns of vegetational landscape and site attributes, and hypothesized the underlying mechanisms. The study area was classified into three vegetation types: grasslands, secondary forests and old‐growth forests. It was determined that the grasslands were formed and maintained by burning; secondary forests were derived from either charcoal woods or forests recovered on abandoned grasslands; and old‐growth forests had suffered the least anthropogenic disturbance. Each past vegetation type showed significant dependency on site attributes such as altitude, slope angle, slope aspect, hydrological topography and distance from the nearest human habitation. The relative importance of these site attributes varied depending on the vegetation type. Grasslands and old‐growth forests, which were the most and the least disturbed sites in the study area, respectively, showed clear contrasts in their dependencies especially on the slope aspect and on elevation. These site attributes were thought to have had influences on each vegetation type by determining the inflammability of the site. Satellite photographs indicated that north‐facing valleys had been relatively wet throughout the fire‐prone spring season. Hence, these areas would have been free from frequent fire, and more likely to preserve old‐growth forests. Ground wetness in spring was thought to be the underlying factor determining the contrasts in past vegetation and land‐use patterns in the area.