Background The southern hilly area is an important area for the construction of "three zones and four zones" ecological security barrier and the main concentrated distribution area of low-quality and low-efficiency plantation in southern China, which have long-term outstanding problems such as soil erosion, low ecological service capacity and poor system stability.

Methods In view of the distribution pattern, evolution characteristics and response to climate change, community structure-soil quality-ecological services coupling mechanism, and multi-objective decision optimization algorithm and path of low-quality and low-efficiency plantation in southern China, the research team selected Changting, Nanning, Ganzhou, Huanggang, and Huangshan city as typical demonstration areas to carry out the "National Key R & D Program of China". The main line of this research is distribution pattern and degradation mechanism of low-quality and low-efficiency plantation ecosystem service, and ecological service improvement and demonstration research should be carried out from three levels.

Results 1) Clarify the spatial and temporal pattern, evolution characteristics, degradation mechanism, the response of community structure and ecosystem services to climate change of typical plantation ecosystem services such as Cunninghamia lanceolata, Pinus massoniana and Moso bamboo in the southern China, and propose the coordinated improvement. 2) Select functional native tree species with high water utilization rate and strong carbon fixation ability, research technologies such as needle and broad-leaved layer mixing, bamboo forest full-time life-cycle operation and so on, and forming low-quality and low-efficiency plantation community structure optimization and carbon fixation increase synergistic improvement technology and mode. 3) Study the technologies of understory vegetation function group construction, biodiversity improvement, understory vegetation renewal, and culvert soil conservation function improvement, and construct the technology and mode of coordinated improvement of understory vegetation ecology and economy. 4) Study the technologies for acidified soil improvement, ecological stoichiometry and nutrient balance regulation, root economic spectrum complementarity and soil nutrient improvement, soil structural obstacle reduction and nutrient utilization improvement, and form soil habitat restoration technology and mode of soil-rhizosphere-microbial interaction. 5) Establish a database of technical model and regional environmental parameters, evaluate the regional differentiation and climate change adaptability of the technology and model of artificial forest quality improvement and ecological service collaborative improvement.

Conclusions Focus on solving the key technical bottlenecks of community structure optimization, induction and restoration of understory vegetation function group, soil habitat restoration, which is applicable to typical plantations such as C. lanceolata, P. massoniana and M. bamboo et al, build a quality and efficiency improvement intelligent decision-making platform of low quality and low efficiency plantation. Finally, this study may provide theoretical basis and technical support for the quality improvement strategy of low quality and low efficiency plantation and the ecosystem service improvement path in southern China.