Posted on 20 May 2015
South China Botanical Garden, Chinese Academy of Sciences (SCBG), CAS carries out studies on the structure, function, mechanisms during the process of degradation and restoration of degraded ecosystems in tropical and subtropical regions of China. It integrates basic research and applied studies by assessing the health status and establishing restoration models at the same time. The Garden is establishing sustainable models for degraded ecosystems such as hilly lands, coastal regions, agricultural fields and urban areas, recognizing that it is critical for the sustainable development of economy in southern China to restore the vegetation and soil of degraded ecosystems.
In 1984, SCBG together with Heshan Forestry Research Institute, established the Heshan Station, to set up demonstration models for comprehensive utilization and exploitation of abandoned hilly lands that can ensure sustainable and concerted development both ecologically and economically. Studies on the relationship between species diversity and stability, structure and function in artificial forest ecosystem have been carried out.
In one project experiments are carried out across various vegetation types with grass land (control plots), monoculture plantations of native tree species or exotic fast-growing tree species, and mixed plantations of native tree species. Issues addressed concern the configuration of pioneer community, tree species adaptation and selection; the impacts of spatial configuration of plant species and communities on the establishment of native tree species and soil biodiversity; variation of soil properties and the carbon balance of different plantation ecosystems in response to vegetation restoration. The results show that legume tree species were more suitable to be pioneer species, while fast-growing tree species were effective to reduce the leaching of soil nitrogen. The impacts of fallen litter and live roots of Eucalyptus and Acacia species on native tree species were examined separately. According to the findings, different strategies for colonization of different native species in those plantations are proposed. Additionally, a simplified system was designed to measure rhizosphere respiration in situ, and the data demonstrated that the contributions of fine and coarse roots were much similar in terms of their contribution to total root respiration; importantly, young plantation of Eucalyptus urophulla was proved to be a strong carbon sink.
Initiated in 2012, a BGCI supported project aims to promote and contribute to forest restoration using native tree species in large-scale pine, eucalyptus and acacia plantations of Heshan County, Guangdong. In the first part of 2013, work continued to grow native species in eucalyptus and acacia plantations as understorey vegetation, including medicinal species (e.g. Millettia speciosa, Gardenia jasminoides, Polygonum cuspidatum, Flemingia stricta), and to study their ecological role and economic benefits. To date, some 9000 saplings of these species have been planted in pilot plots. In the same vein, to enhance the conservation value of the plantations, some 1000 plants of three native tree species (Machilus chekiangensis, Phoebe bournei, Aquilaria sinensis) were introduced to the plantations.