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Montane cloud forest is one of the most endangered ecosystems. However, there are few comprehensive studies on the distribution of subtropical montane cloud forest (SMCF). Chamaecyparis forest is one type of SMCF in Taiwan, distributed across the whole island. This study describes eleven types of this forest in Taiwan based on the Braun-Blanquet approach. Plots were selected from the National Vegetation Database of Taiwan. Two alliances were defined, both of which belong to the order Fagetalia hayatae. Topography and altitude explain the contrasting habitat requirements of these two alliances, whereas seasonality of moisture, soil properties and altitude explain differences in floristic composition at the association level. The alliance of Chamaecyparidion formosanae on slopes and ridges includes coniferous or mixed coniferous and evergreen broad-leaved forests; it is found at higher altitudes and is more influenced by the summer monsoon than the other alliance. Five associations are defined within this alliance. The alliance of Pasanio kawakamii - Machilion japonicae growing on slopes and in valleys contains evergreen broad-leaved forests or forests with a mixture of coniferous and evergreen broad-leaved species. Six associations can be determined under the alliance of Pasanio kawakamii- Machilion japonicae. Classification of each syntaxon was formalized using Cocktail Determination Key. [ABSTRACT FROM AUTHOR]

Liaotung oak (strictly named as Quercus wutaishanica Mayr, but usually called Q. liaotungensis Koidz) is the main dominant tree species in deciduous broad-leaved forests and mixed coniferous and broad-leaved forests occupying the warm-temperate zone and temperate zone of China. It plays important roles in soil and water conservation. We collected occurrence data of Liaotung oak together with environmental variables, and used 24 environmental layers as indicators of climate, human disturbance and soil characteristics (at a spatial resolution of 5 arc-min) across China. The genetic algorithm for rule-set prediction (GARP) was used to predict the potential distribution area of Liaotung oak. Forward selection, Monte Carlo permutation tests and variation partitioning methods were used to identify the key environmental factors that determined the distribution pattern of Liaotung oak. The results show that (1) GARP predicts the potential distribution area of Liaotung oak with high accuracy, with areas under the receiver operating characteristic curve (AUC) and Kappa index values being relatively high (0.96 ± 0.01, 0.91 ± 0.01); (2) the highest probability of Liaotung oak occurrence is located mainly in Gansu, Shaanxi, Shanxi, Henan, Shandong, Hebei, Liaoning, Jilin, and Heilongjiang provinces in China; (3) climate and disturbance intensity are predominant in determining the geographical boundary of Liaotung oak, with human footprint and precipitation of the coldest quarter being the most important (both explaining 71% variation) among the factors investigated across continental China. While climate and soil factors play important roles in determining the suitability index of Liaotung oak, soil organic carbon and temperature are the critical factors (both explaining 55% variation) among the factors investigated across the potential distribution area. [ABSTRACT FROM AUTHOR]