Fig. 1 Location of the study area and its vegetation 1: Subalpine conifer forest 2: Pines pumila scrub, alpine heath and alpine desert 3: Betula ermanii forest, Alnus maximowiczii scrub and bare land 4: Others

Fig. 2 Altitudinal distribution of vegetation, slope gradient and areas from the grid method 1: Vegetation (Ab: Abies veitchii-a. mariesii forest B : Betula ermanii forest P: Pinus pumila scrub : other) 2: Gradient of slopes 3: Areas converted from the numbers of points (0.04km for one point)

Fig. 4 Altitudinal distribution of plant communities concerning slope exposures W: Slopes having a component of western exposure E: Slopes having a component of eastern exposure 1: Pines pumila scrub 2: Betula remanii forest 3: Abies veitchii-a. rnariesii forest 4: others 5: The proportion of slope where its gradient is above 35 degrees. Fig. 3 Relationship between plant communities and gradients of slopes. The data were obtained from the points above 2,400 m a.s. 1. Ab: Abies veitchii-a. mariesii forest B: Betula ermanii forest P: Pinus pumila scrub Al: Alnus maximowiczii scrub

Fig. 5 The vegetational landscape map of west facing slope on Mt. Ioh 1: Abies veitchii and A. mariesii 2: Standing dead trunks of A. veitchii and A. mariesii or fallen ones by a storm 3: Betula ermanii 4: Alnus maximowiczii 5: Pinus pumila 6: Rubble fields 7: Block fields 8: Alpine heath communities 9: Meadow 10: Area covered with tree or subtree forest

Fig. 6 Distribution of heights of plant communities A: locations of the measurement sites B: heights of plant communities on the block-diagram (1: Abies veitchii-a. mariesii forest 2: Betula ermanii forest 3: Alnus maximowiczii scrub 4: Pinus pumila scrub 5: Windblown heath or bare land

Fig. 7 Distribution of deformed trees and their directions of deformations which indicate presumably the prevailing wind direction in winter 1: The wind direction indicated by deformed trees 2: Areas of forest

The Forest Limit on Yatsugatake Mountains: With Special Reference to Its Relation to Topography Sotaro TANAKA The author investigated the altitudinal forest limit on Yatsugatake Mountains, Central Japan. Japanese researchers have recognized the altitudinal forest limit in Japan as a dividing line between the subalpine and the alpine zones in altitudinal zonation of mountain systems. However, some questions have recently been proposed with reference to this distinction. The main purpose of this paper is to present the materialized landscape of the altitudinal forest limit and to elucidate the relationship between this landscape and topographic factors. The reason is that this landscape is complexly formed by many orographic factors which are concerned with the topograpy. Consequently the author intends to compare the result of this study with those of other mountains. In the first place, the author drew a vegetation map of the study area (1:25,000 in scale) with the aid of air photographs and field observation (Fig. 1). Then, in this map, grid data relating to the vegetation and topographic elements are obtained from about 1,200 points in total. The sum of these data is shown in Figs. 2, 3 and 4. Moreover, a precise landscape map of the west facing slope of Mt. Job (2,756 m a.s.l.) is illustrated (Fig. 5). The results can be summarized as follows:

1) The forest limit appears at the Betula ermanii forest which stands above the subalpine conifer forest. The Pinus pumila scrub (the so-called "Krummholz") extends above the forest limit. 2) The Betula ermanii forest is distributed on steep slopes or concave slopes of valleys where the snow cover lasts long. 3) The Pinus pumila scrub is distributed on convex slopes of ridges where the wind blows hard and on xeric block slopes. 4) The elevation of the forest limit is higher in the valleys than on the riges. It is also higher on the E-facing slopes than the W-facing slopes. These disparities in elevation reach about 100m on average.