Explication of community types and habitat characteristics in subalpine coniferous forest

1.奈巴山山地带上部和亚高山带下部森林的分布、结构和生境特征：(1)山地水曲柳带与亚高山冷杉带交界处的海拔高度随地形变化，平缓坡面上的水曲柳林的上限位于较高的海拔(1700-1750ma.s.l)；较先前承认的(约1500米升)为高。在海拔1750m的山脊上发现了多叶铁杉林。(2)水曲柳林与水曲柳、冷杉混交林的林下植被特征相似。而以针叶林(冷杉和多叶铁杉)为主的森林中含有许多具有亚高山针叶林特征的物种。(3)水曲柳林(暗棕壤)表土层的养分状况和有机质分解情况相对好于t…更多的冷杉林(湿铁泥土)和多叶铁杉林(干泥土)。缓坡冷杉-多叶铁杉混交林结构与更新在Naeba山小松原沼泽附近(1)两个树种在各层中都表现出集合性。多叶铁杉各层间的分布格局呈正相关。(2)虽然各生境均有马尾冷杉幼苗，但多叶铁杉的幼苗仅在树桩或土丘上发现。地上生长的冷杉幼树被认为是连续生长并达到冠层的。(3)凸生生境中存在乔木，尤其是多叶铁杉。甚至在土壤呈粘土质地的栖息地也发现了冷杉和许多被连根拔起的树木。这些被连根拔起的树木为多叶铁杉提供了良好的更新场所。(4)通过这两个树种的生境条件和更新方式，形成并维持了马尾松-多叶铁杉混交林。较少

1. Distribution, structure and habitat characteristics of forests in upper part of montane zone and lower part of subalpine zone of Mt.Naeba, Niigata Professor.(1) The altitude of the boundary between montane Fagus crenata zone and subalpine Abies mariesii zone changed along topography ; the upper limit of Fagus crenata forests on an even slope lay at higher altitude (1700-1750 m a.s.l.) than that of formerly recognized (ca.1500 m a.s.l.). Tsuga diversifolia forest was found at a ridge in the altitude of 1750 m.(2) Characteristics of understory vegetation were similar between Fagus crenata forests and mixed ones consisted of Fagus crenata and Abies mariesii. However, forests dominated by coniferous trees (Abies mariesii and Tsuga diversifolia) contained many species which were characteristic of subalpine coniferous forests.(3) The nutrient condition and decomposition of organic matter in upper soil horizons of Fagus crenata forests (dark brown forest soil) were relatively better than t … More hose of Abies mariesii forests (wet iron podzolic soil) and Tsuga diversifolia forests (dry podzolic soil).2. Structure and regeneration of Abies mariesii-Tsuga diversifolia mixed forest at a gentle slope (1580 m a.s.l.) near Komatsubara Bog in Mt.Naeba.(1) Both tree species showed assemblage in every stratum. The distribution pattern between strata of Tsuga diversifolia showed positive correlation.(2) Although seedlings of Abies mariesii were found at every habitat, those of Tsuga diversifolia were found only on stumps or mounds. Saplings of Abies mariesii growing on the ground were considered to grow successively and reach the canopy layr.(3) Trees especially Tsuga diversifolia were found on convex habitats. Abies mariesii as well as many uprooted trees were found at even habitats where the soil showed clayy texture. Such uprooted trees presented good regeneration sites to Tsuga diversifolia.(4) Abies mariesii-Tsuga diversifolia mixed forest was formed and maintained through such habitat conditions and regeneration style of the two species. Less