- 期刊
Vegetation of Chamaecyparis montane cloud forest in Lalashan Forest Dynamics Plot
摘要
To study how species composition and physiognomical structure of Chamaecyparis montane mixed cloud forest in Taiwan changes along main soil, topographical and microclimatic variables on a small scale, we established a 1-ha Lalashan Forest Dynamics Plot in northern Taiwan (24°43' N, 121°26' E, elevation 1758-1782 m a.s.l.). Plot is affected by prevailing NE wind direction related to winter monsoon, and by seasonal fog frequency with highest fog density in autumn and winter. We finished the first census of all woody species in August 2020, and collected environmental factors related to soil and topographical properties, measured microclimate and soil moisture within the plot. In total, we recorded 5220 individuals with diameter at breast height ≥ 1 cm. These belong to 65 species, 42 genera and 29 families, with a basal area of 69.1 m^2 ha^(-1), and are dominated by Chamaecyparis obtusa var. formosana, Rhododendron formosanum and Quercus sessilifolia. Modified TWINSPAN classified vegetation into three types (ridge, east-facing slope and valley). Unconstrained ordination showed that the main gradients behind species composition changes are related to windwardness and convexity. Both east-facing slope type and valley type have relatively lower temperatures than ridge type, especially during summer. Convexity is related to soil moisture gradient (from dryer convex to wet concave sites). From soil properties, pH is negatively and phosphorus is positively related to topographical convexity. Collected data will serve as a baseline for future resurveys and monitoring changes within this montane cloud forest.