In this paper,some problems related to planning and designing of closing off hillsides for tree growing,such as space arrangement,period of closing,measures of silviculture,are discussed,and some viewpoints are presented.

The results showed that: With the increase of enclosing years,the density of soil organic carbon grows increasingly,while the highest value of plant organic carbon density occurs in the 20 years of enclosing,and the plant carbon intensity of enclosing for 25 years is slightly lower than that of enclosing for 20 years,showing a lowering trend.

This paper takes the average years of education as an index to denote the state of human capital,and uses three statistical indexes of measuring the distribution of human capital to calculate the parameters of the spatial distribution of human capital in China.

In order to shorten the service life of breeding, accelerate breeding paces, improve breeding efficiency, this paper explicates it mainly from the following aspects .

The conclusion shows that the average years of schooling of household laborers significantly increase the farmers average income per capita;the households with technically trained labour have significantly higher average income per capita than the rural households without technically trained labour;the increase in the amount of technically trained la.