Four aspects of the techniques of containerized nursery, including container size, growing medium, root control and seedling density, were systematically studied for Melia azedarach and Pterocarya stenoptera, which are two native afforestation and reforestation species in Jiangsu province.

Experimental results showed that the positive effect of seedling density on seedling quality was enhaneed with the increasing of seedling age.

Based on domestic studies about insurance scale,this paper analyses the significant affecting factors which influence insurance density in China by using the method of co-integration regression,and sets Compertz model to simulate insurance density in China,which means insurance industry in China is promising.

The paper explores the spatial correlation of China\'s provincial insurance density through spatial econometrics,and finds that the insurance density is characterized by regional clustering and its convergence in the national level has been strengthened at the same time.

Although China’s insurance industry has gained a rapid and continuous development in recent years,it is far from that of developed countries in insurance density and depth,which suggests that the effective demand of the Chinese market for insurance fails to be uncovered.