Land Economic Density in China:Regional Differences and Influencing Factors

With the help of the Theil index,this paper analyzes the regional and intra-regional disparities in the Land Economic Density(LED)of the provincial-level regions in China from 2008 to 2017.The Pearson correlation coefficient is also employed to reveal the relationship between influencing factors and the LED of the empirical regions,so as to further identify differences in the LED of different regions.The paper finds that firstly,the average LED on the national scale has grown gradually from about 787 million yuan/km^(2) in 2008 to around 1,396 million yuan/km^(2) in 2017.Secondly,the intra-regional disparity in LED shows a decrease trend.Conversely,the regional disparity in LED has increased year by year.Thirdly,the LED of different regions has different correlations with their influencing factors.Finally,both education and technology input have a significantly positive correlation with the LED,and a negative correlation with urban-rural consumption ratio,which indicates that improving the education and technology input could balance regional development and narrow the development gap between urban and rural areas.

Relationship Between Social Economic Agglomeration and Labor Productivity of Core Cities in Northeast China

Dalian, Shenyang, Changchun and Harbin are the four core cities which play an essential role in terms of promoting the economic development in Northeast China. In this paper, the impact of urban agglomeration on labor productivity is explored by making comparisons among these four cities. The model used for analysis is a classical model derived from previous studies. Some indicators, such as population density and economic density, were selected to examine the impact of urban agglomeration on the labor productivity based on the time-series data for the four cities from 1990 to 2007. The four main conclusions are： l） The promotion from the growth rate of population density on the growth rate of labor productivity is limited. 2） The negative relationship exists between the growth rate of employment density and the growth rate of labor productivity. 3） Agglomeration effect exists in the four cities, the highest one is Dalian, Shenyang takes the second place, followed by Changchun and Harbin, and the predominant promotion exerted on the labor productivity is the output density.

Basic density, extractive content and moisture sorption properties of Pinus pinaster wood infected with the pinewood nematode, Bursaphelenchus xylophilus

The pinewood nematode（PWN）, Bursaphelenchus xylophilus, has become one of the most severe threats to pine forest worldwide. Nematodes, migrating through resin canals and feeding on the living cells, induce rapid metabolic changes in ray parenchyma cells, create cavitation areas, decrease xylem water content and oleoresin exudation, and cause necrosis of parenchyma and cambial cells. This study focused on the impact of PWN infection on technological parameters of wood and evaluated the impact of anatomic and biochemical incidences of tree defense reactions on basic density, extractive content and moisture sorption properties of Pinus pinaster wood.Samples of infected and uninfected wood were studied.The presence of nematodes reduced wood basic density by2 % and decreased the total content of extractives in infected wood as compared with uninfected（5.98 and8.90 % of dry wood mass, respectively）. Extractives in infected trees had inverse distribution along the trunk as compared with uninfected trees. The adsorption isotherms for infected and uninfected wood had similar positioning.We recorded differences（some statistically significant） in the equilibrium moisture content of infected and uninfected wood under varying environmental conditions. Despite the verified differences in wood basic density, extractive content and moisture sorption properties, the overall conclusion is that the PWN had a slight impact on these characteristics of wood.