Location
Jianfengling National Key Field Station of China (JNKFS, 18°23′– 18°50′N, 108°36′–109°05′E) was located in Jianfengling National Natural Reserve of China, Ledong county, Hainan province. The station was in the charge of Research Institute of Tropical Forestry, Chinese Academy of Forestry. The flux tower (18° 43′ 47.0″N，108°53′ 23.8″E, 890m ASL) was located 5 km east of the station building, in an area of primary forest of tropical mountain rain forest.;
Climatic
The Jianfengling region experiences a tropical monsoon climate, characterized by high daily and annual temperatures, humidity, and plentiful precipitation. JFL’s annual average temperature was 19.8°C; the minimum temperature was 4.0°C, and the annual accumulated temperature was 7204°C. The mean relative humidity was 88%, and the annual average precipitation was 2449 mm. Approximately 80%–90% of the annual precipitation falls during the wet season, between May and October.;
Vegetation and soil
There distributed typical tropical mountain rain forest around site, and the forest is on flat terrain and has a closed canopy with a mean height of approximately 25-28 m and emergent trees reaching up to 35 m. There are few indications of recent anthropogenic disturbance. This forest can be classified as 'primary' with abundant large logs, numerous epiphytes, an uneven age distribution, and emergent trees. Dominant species in the forests are Livistona saribus (Lour.) Merr. ex A. Chev (Palmaceae), Lasianthus calycinus Geddes (Rubiaceae), Symplocos anomala Brand (Symplocaceae), Symplocos lancifolia Sieb. & Zucc (Symplocaceae), Ardisia quinquegona Bl. (Myrsinaceae), Calamus rhabdocladus Burret (Palmaceae), Psychotria hainanensis Li (Rubiaceae), Dacrycarpus imbricatus (Bl.) de Laub. var. patulus de Laub. (Podocarpaceae), Symplocos congesta Benth. (Symplocaceae), Syzygium araiocladum Merr. & L. M. Perry (Myrtaceae), Pinanga discolor Burret (Palmaceae), Alseodaphne hainanensis Merr. (Lauraceae). The soil is a lateritic yellow soil with a depth of 100～120cm. Soil organic carbon content is about 2.4%. ;
Observation system
A 50 m tower was instrumented for eddy covariance measurements which commenced in July, 2006. Eddy-flux measurements were made at a height of 45 m with a sample rate of 10 Hz. Turbulent fluxes of sensible heat (H), latent heat (LE), and carbon dioxide (CO2) were measured with an eddy covariance system that consisted of a three-dimensional sonic anemometer (CSAT3, Campbell Scientific, Inc.) and an open path carbon dioxide/water vapor (CO2/H2O) infrared gas analyzer (IRGA) (LI 7500, LI-COR, Inc.). Sensor signals were recorded by data loggers (CR3000, Campbell Scientific, Inc.) at a rate of 10 Hz. Vertical fluxes of CO2, H and LE were obtained via 30-min mean covariance between vertical velocity and the respective scalar fluctuation. Along with the turbulent fluxes a variety of micrometeorological variables were also measured as 30-min averages of 1-s readings. Net radiation (Rn) was measured the top of the tower. Wind speed, air temperature and relative humidity were measured at ten heights of 2m, 5m, 10.5m, 15m, 21m, 25m, 29m, 37.5m, 45m and 50m with temperature/humidity probes and wind sentry unit respectively. Five thermocouples were placed at 10-, 30-, 50-, 80-, and 100-cm depths below the soil surface to measure soil temperature. ;
Principal Investigator
Yide Li
E-mail: liyide@126.com