A living laboratory
Positioned on the Tropic of Cancer, a latitude known for arid deserts, Dinghu Mountain is lush. Designated in 1956, it is China's first national nature reserve. The reserve protects a southern subtropical evergreen broad-leaved forest that has remained largely undisturbed for more than 400 years. The reserve became one of the country's first UNESCO Biosphere Reserves in 1979, the same period that scientific monitoring began in earnest.
The Dinghushan Forest Ecosystem Research Station was established here in 1978. It is part of the Chinese Ecosystem Research Network (CERN), a nationwide system for long-term environmental tracking. Scientists at Dinghu manage a series of permanent plots, including a 20-hectare plot established in 2005 containing 71,617 individual woody plants. Here, every tree with a diameter of at least 1 centimeter is measured, mapped, and identified. Biodiversity is high, with the reserve containing over 2,291 species of higher plants and 277 species of birds. Data from these plots on tree growth, mortality, soil composition, and water cycles provide a continuous, high-resolution picture of the forest's health.
Decades of discovery
Over four decades of continuous data collection have produced fundamental insights into how ecosystems function. One of the most significant discoveries from Dinghu Mountain changed the understanding about mature forests. It was traditionally thought that old-growth forests were "carbon neutral," meaning their carbon uptake was balanced by release from decomposition. Research published in 2006, based on 24 years of soil data from 1979 to 2003, showed that the 400-year-old forest was still a carbon sink. The soil's top 20 centimeters were steadily accumulating organic carbon, a finding that reshaped global carbon cycle models.
The station has also been a site for studying the effects of air pollution. As a downwind recipient of industrial emissions from the Pearl River Delta, the mountain's ecosystem was a natural experiment. Long-term monitoring of rainfall chemistry provided decades of data on acid deposition. This information helps scientists understand how increased nitrogen and sulfur inputs alter soil chemistry and affect the nutrient cycles of a subtropical forest. These findings have informed both regional pollution controls and global atmospheric science.