Lalashan Forest Dynamics Plot: an example of subtropical montane cloud forest in Taiwan
Zelený, David; Chen, Ting; Lee, Yi-Nuo; Lin, Kuan-Fu; Lin, Po-Yu; Wu, Kun-Sung
Institute of Ecology and Evolutionary Biology & School of Forestry and Resource Conservation, National Taiwan University, Taipei, Taiwan
Subtropical montane cloud forest (SMCF) represents a unique vegetation type with limited distribution in subtropical regions of mountainous areas across the world. In Taiwan, SMCF is distributed mainly in the northern and central part of the island, at elevations between 1500 and 2500 m a.s.l., being replaced by tropical montane cloud forest in the southern part of the island. SMCF in Taiwan is dominated by evergreen broadleaf woody species, with frequent large coniferous trees (e.g., Chamaecyparis, Taiwania and Tsuga) and an admixture of deciduous species (including relict Fagus hayatae). Trees are often covered by abundant epiphytes, mostly ferns and lycophytes, which also dominate forest understory. Frequent fog occurrence results in a peculiar combination of environmental conditions, including lower temperature, reduced solar radiation, higher air humidity and waterlogged soils. These, together with pronounced nutrient limitation, create a unique habitat inviting for deeper ecological understanding. In this Virtual Excursion, we wish to introduce you to our one-hectare Lalashan Forest Dynamics Plot (24°42’N, 121°26’E, elevation 1758-1782 m a.s.l.), established in 2019 at a wide ridge between Lalashan and Tamanshan mountains, inside the Chatianshan Nature Reserve in the northern part of Taiwan. Our forest dynamics plot represents a typical example of Chamaecyparis montane mixed cloud forest. Due to its location on the ridge exposed to chronic winds caused by northeastern monsoons, the plot also includes a strong windward-leeward gradient. Within the plot, separated into a grid of 100 10 m × 10 m subplots, we conducted a standard survey of woody species, following the ForestGEO Forest Census Protocol (recording, tagging and mapping all woody individuals, DBH ≥ 1 cm). In addition to woody species, we also surveyed understory (herbs, seedlings of woody species, and lianas), in the permanently delineated 2 m × 2 m quadrats in the centre of each 10 m x 10 m subplot. Data collected within the plot allowed us to prepare a detailed and fine-scale vegetation description of woody and herb species composition. For environmental factors, we collected detailed topographical and soil measurements, including the teabag decomposition experiment. We also set up a completely equipped microclimatic station (100 m from the plot in the open saddle), including also the visibility sensor to estimate the fog frequency. We also focused on leaf functional traits of broadleaf species and studied how is their inter- and intraspecific trait variation related to the effect of chronic wind and heterogeneous topographical and soil conditions. An important aim of our permanent plot is long-term vegetation monitoring by repeated resurveys (every five years). Availability of detailed and long-term microclimatic data will allow us to link compositional changes of woody and herb species to climatic trends in a near future.