Location

Guangdong Nanling Forest Ecosystem National Observation and Research Station is affiliated with Institute of Guangzhou lnstitute of Geography, Guangdong Academy of Sciences. The station locates at No. 1, Nanling National Station, Guangdong Nanling National Nature Reserve, Ruyuan Yao Autonomous County, Shaoguan City, Guangdong Province. (1) Nanling Dadongshan Carbon Flux Tower; Longitude: 112°43'5.145"E; Latitude: 24°55'35.598"N; Altitute:763m; (2) Nanling Xiaohuangshan Carbon Flux Tower; Longitude: 113°2'26.331"E; Latitude: 24°54'36.794"N;Altitute: 986m; (3) Nanling Wuzhishan Carbon Flux Tower; Longitude: 113°00′23.94"E; Latitude: 24°56′05.11"N; Altitute:1148m.

Climatic

It has a humid monsoon climate transitioning from the central subtropics to the southern subtropics, with characteristics of mountainous climate. The annual average temperature is 17.7°C, with extreme maximum temperatures reaching 39.9°C and extreme minimum temperatures dropping to -6.9°C. The frost period lasts for up to 100 days. The region receives abundant rainfall, with an average annual precipitation of 1705 millimeters, and in some years, it can reach as high as 2495 millimeters. Most of the rainfall occurs between March and August, and the average annual relative humidity is 84%. There are frequent clouds and fog in the region, with an average of approximately 1234 hours of sunshine per year and a sunshine rate of 40%.

Vegetation and soil

The vegetation type is subtropical evergreen broadleaf forest. Below 700 meters in altitude, the area is dominated by species such as Castanopsis fargesii, Castanopsis fordii, Castanopsis lamontii, Castanopsis fissa, Castanopsis faberi, Schima superba, Exbucklandia tonkinensis. In mountainnous areas above 700 meters, the main species are Castanopsis carlesii, Castanopsis eyrei, Machilus rufipes, Schima argentea, Lithocarpus hancei. At altitudes between 1300 and 1700 meters, there are montane evergreen deciduous broadleaf mixed forests, with dominant species including Quercus multinervis, Quercus sessilifolia, Castanopsis eyrei, Castanopsis platyacantha. Common deciduous broadleaf trees include Fagus longipetiolata, Fagus lucida, Liquidambar acalycina, Pterostyrax psilophyllus, Perkinsiodendron macgregorii. In the ridge zones or steep cliffs within this altitude range, small patches of Pinus kwangtungensis forests, Nothotsuga longibracteata forests, and Fokienia hodginsii forests can be found, sometimes intermixed with the aforementioned broadleaf trees. Due to insufficient elevation, conifer-broadleaf mixed forests have not formed. These native forests have undergone various degrees of disturbance, resulting in different types of successional communities such as grasslands (dominated by Miscanthus floridulus,Miscanthus sinensis, Eulalia speciosa, Eulalia quadrinervis, Ischaemum ciliare, Arundinella hirta, Imperata cylindrica, Dicranopteris pedata), shrublands (dominated by Rhododendron simsii, Rhododendron ovatum, Rhododendron ovatum, Vaccinium bracteatum, Artocarpus parvus, Quercus fabri, Castanea mollissima, Acer davidii), subtropical coniferous forests (below 1300 meters dominated by Pinus massoniana), subtropical deciduous broadleaf forests (below 1300 meters dominated by Alniphyllum fortunei, Carpinus viminea, Betula luminifera), as well as artificially planted Cunninghamia lanceolata forests and Phyllostachys edulis forests. Above 1700 meters, due to strong winds, a unique appearance of dwarf forests is formed, with dominant species including Quercus multinervis, Rhododendron latoucheae, Rhododendron fortunei, Rhododendron simiarum, Symplocos pseudobarberina, Fargesia spathacea, Pleioblastus amarus.

The predominant soil types are granite, sandstone shale, and limestone. Due to the significant variation in elevation on the mountainside, there is a distinct vertical distribution of water and thermal conditions, resulting in different soil types formed from the weathering of parent rocks. Below 700 meters, the soil type is mountainous red soil; between 700 and 1500 meters, it is mountainous yellow soil; between 1500 and 1800 meters, it is mountainous subsoil yellow soil; and above 1800 meters, it is mountainous shrub meadow soil. These soils have a low degree of parent rock weathering, shallow soil depth, but exceptionally high organic matter content.

The soil organic matter content ranges from 34.24 g/kg to 156.87 g/kg, with an average value of 82.78 g/kg, indicating a relatively low content. The available phosphorus content ranges from 0.66 mg/kg to 12.18 mg/kg, with an average value of 2.49, which is generally low. The available potassium content ranges from 48.65 mg/kg to 130.68 mg/kg, with an average value of 81.22 mg/kg, indicating a moderate level overall. The soil pH ranges from 4.00 to 4.91, indicating strongly acidic soil. The bulk density of the soil ranges from 0.676 g/cm3 to 1.219 g/cm3, with an average value of 1.06, indicating suitable soil conditions. The percentage of sand particles (2-0.05mm) has an average value of 55.82%, while the percentage of silt particles (0.05-0.002mm) has an average value of 20.71%. The percentage of clay particles (<0.002mm) has an average value of 22.64%.

Observation system

(1)Nanling Dadongshan Carbon Flux Tower: IRGASON Integrated CO2/H2O Open-Path Gas Analyzer & 3D Sonic Anemometer；(2)Nanling Xiaohuangshan Carbon Flux Tower: IRGASON Integrated CO2/H2O Open-Path Gas Analyzer & 3D Sonic Anemometer; (3)Nanling Wuzhishan Carbon Flux Tower: IRGASON Integrated CO2/H2O Open-Path Gas Analyzer & 3D Sonic Anemometer.

(1)Nanling Dadongshan Carbon Flux Tower: The flux tower has a height of 30 meters. The ultrasonic anemometer and infrared analyzer are installed at a height of 20 meters. Air temperature, humidity, wind speed, and wind direction sensors are installed at heights of 2, 4, 8, 17, 19, and 23 meters. The radiation sensor is installed at a height of 23 meters. Soil temperature and moisture sensors are installed at depths of 5, 10, 15, 20, 40, 60, and 100 centimeters. (2)Nanling Xiaohuangshan Carbon Fluxt Tower: The flux tower has a height of 32 meters. The ultrasonic anemometer and infrared analyzer are installed at a height of 16 meters. Air temperature, humidity, wind speed, and wind direction sensors are installed at heights of 2, 4, 8, 14, 20, and 24 meters. The radiation sensor is installed at a height of 20 meters. Soil temperature and moisture sensors are installed at depths of 5, 10, 15, 20, 40, 60, and 100 centimeters. (3)Nanling Wuzhishan Carbon Flux Tower: The flux tower has a height of 30 meters. The ultrasonic anemometer and infrared analyzer are installed at a height of 26 meters. Air temperature, humidity, wind speed, and wind direction sensors are installed at heights of 2, 5, 9, 16, and 30meters. The radiation sensor is installed at a height of 24 meters. Soil temperature and moisture sensors are installed at depths of 5, 10, 15, 20, 40, 60, and 100 centimeters.

(1)Nanling Dadongshan Carbon Flux Tower: The data sampling frequency is 10 Hz, and the average flux time is 30 min ； (2)Nanling Xiaohuangshan Carbon Flux Tower: The data sampling frequency is 10 Hz, and the average flux time is 30 min ; (3)Nanling Wuzhishan Carbon Flux Tower: The data sampling frequency is 10 Hz, and the average flux time is 30 min .

(1)Nanling Dadongshan Carbon Flux Tower: January 2021；(2)Nanling Xiaohuangshan Carbon Flux Tower: November 2023; (3)Nanling Wuzhishan Carbon Flux Tower: November 2023.

Principal Investigator

Ping Zhou     E-mail: pzhou@gdas.ac.cn