A Quaternary geoecological study on disturbance regime and vegetation structure in volcanic areas

地貌演化甚至在地质时间尺度上都能引起生境环境的变化，使植被景观长期处于不平衡状态。重要的是要澄清地形对植被的影响，在一个世纪和千年的时间尺度，以及在几年和几十年的时间尺度。为了阐明山地演变对植被的长期影响，对戴森、屋科岳和阿波山的植被边界结构和成因进行了研究。在戴森上，在海拔1100- 1300米之间形成了一条明显的森林线，这与熔岩圆顶和岩屑堆积物的地质边界相吻合。由于土壤发育不良，没有森林能够在山顶熔岩丘上发展，森林线的位置不是由大气候或地形气候条件控制的，而是由晚更新世至全新世早期形成的熔岩丘上的未成熟土壤控制的。在Yakedake-Abo地区，在海拔1100- 1700 m之间形成了亚高山-山地森林边界，这与光滑和切割斜坡的地形边界相吻合。在冰后期解剖形成的陡坡上，树冠间隙形成的频率较高。这可能会导致阔叶树在海拔高度的分布极限建立。在某些情况下，巨石覆盖阻止阔叶树建立在光滑的斜坡上。冰后期的解剖移走了巨石覆盖层，改善了土壤条件。这表明，植被边界已沿着与冰后期斜坡解剖在Yakedake-阿波地区发展。

Landform evolution can cause changes in habitat environments even on a geological time scale, keeping vegetation landscape in disequilibrium state for a long period of time. It is important to clarify landform effects on vegetation over a timescale of centuries and millennia, as well as at a timescale of years and decades. The structure and causal factors of vegetation boundaries were studied on Mounts Daisen, Yakedake, and Abo to clarify the long-term influences of mountain evolution on vegetation. On Mount Daisen, a distinct forest line formed at between 1100- and 1300-m elevation, which coincided with the geological boundary of the lava dome and talus deposits. No forest stands were able to develop on the summit lava dome because of poor soil development, and the position of the forest line was controlled not by macroclimatic or topoclimatic conditions but rather by the immature soils on the lava dome that formed during the late Pleistocene to early Holocene. In the Yakedake-Abo area, a subalpine-montanous forest boundary formed at between 1100- and 1700-m elevation, which coincided with the landform boundary of the smooth and dissected slopes. On steep slopes created by post-glacial dissection, frequency of canopy-gap formation is higher. This may cause broad-leaved trees to establish at the elevation of altitudinal limit of the distribution. In some cases, boulder cover prevents broad-leaved trees from establishing on smooth slopes. Post-glacial dissection has removed the boulder cover, improving edaphic conditions. These suggest that the vegetation boundary has been developed along with post-glacial slope dissection in the Yakedake-Abo area.