Forest is the first major form of terrestrial ecosystem and plays an important dominant role in global carbon cycle. In this study, we developed an age - based volume - to - biomass method to estimate the carbon storage of Chinese forests between 1973 and 2003 by using inventory data of six periods and forest biomass data obtained from direct field measurements. The results show that the total vegetation carbon storage of Chinese forests in the six periods (1973～ 1976, 1977～1981, 1984～1988, 1989～1993, 1994～1998 and 1999～2003) is 3.8488 PgC, 3.6960 PgC, 3.759 PgC, 4.1138 PgC, 4.6563 PgC and 5.5064 PgC, respectively. Although the results of different periods is fluctuates their trends are an increase with the time. Especially, since 1980s the total vegetation carbon storage of Chinese forests has increased 1.8104PgC and accumulated about 0.0823PgC per year. It means that Chinese forests play a role as a significant sink of atmospheric carbon dioxide in that period. On the other hand, the mean carbon density of Chinese forests has increased 3.001Mgha- 1 since 1970s, and that of young and middle- aged forests has increased 5.2871 and 0.6022Mgha - 1, respectively, but that of mature forests has decreased by 0.7581Mgha- 1. This phenomenon suggests that the carbon fixation ability of Chinese forests primarily derives from forest plantation and it would be enhanced with carbon storage and carbon density increasing of young and middle- aged forests. The carbon stocks and densities of Chinese forests vary greatly in space. The larger carbon storage is primarily found in north eastern and south western regions, and higher C density mostly occurs in north eastern, south western and north western regions. These spatial distribution characteristics of carbon storage and mean C density in Chinese forests are prominently determined by human activities.
Soil erosion has caused the a ttention of the whole world, and the paradigm of soil erosion control is the hotspot in the research of water and soil conservation. This paper introduces the process of the paradigm in science research and the effect on soil erosion control. And same time, the relationship between paradigm of soil erosion control and ecological paradigm was discussed. It also showed that ecological theory has important effect on soil erosion science, and ecological factor has to be considered in the research of soil and water loss control. There is an interactive relationship between process of soil erosion and ecology, which is coupling relationship in supplement each other. Some theories in ecology, such as natural equilibrium theory, systemic nonequilibrium theory and hierarchical patch dynamics theory have profound effect on the development of soil erosion science, and been put in practice in to some extent. Ecological environment balance theory must be emphasized on the research of soil erosion control.
The vertical distribution of both the concentration and composition characteristics of saturated hydrocarbons in soil samples collected from 7 soil profiles in Tianjin has been investigated. The vertical variation patterns of saturated hydrocarbons composition along the soil profiles with different environmental conditions have been discussed. The results showed that the concentrations and chemical compositions of saturated hydrocarbons were significantly different in the surface soil of different locations. The concentrations were higher in the soil samples from suburban area than rural area. Generally, concentrations of saturated hydrocarbons in the upper horizons from 0 to 30cm were much higher than those in the bottom soils where concentrations were constant. The concentration of saturated hydrocarbons changes dramatically along the profile, reaching a higher concentration in the topsoil. The composition changes of normal alkanes, sterane and terpane in soil with the depth were complex. It also reveals that the primary sources of saturated hydrocarbons in the surface soils were from a mixture of petroleum (including diesel, gasoline and their products of uncompleted combustion) and higher plants, and the petroleum is the primary source of the suburban area. The surface soil of different soil profiles had different contamination sources. The different horizons had similar composition characteri- stics, indicating the similar contamination sources. However, in the bottom soils, the composition characteristics and geochemical indices of normal alkanes were significantly distinct. The sources were different with the surface soils and complex for the normal alkanes in the bottom soils, which may be in connection with both the degradation of soil organic matter and the moving down of saturated hydrocarbons in the topsoil. For sterane and terpane in the profiles which had a high concentration of saturated hydrocarbons in the topsoil, the character of sterane and terpane compositions were similar. Accordingly, in the profiles with a high concentration of saturated hydrocarbons in the topsoil, the bottom soil was influenced by downmoving of the terane and terpane from the topsoil.
Owing to vegetation construction in the Loess Plateau, much attention has been paid to soil desiccation by vegetation for many years. Right thinking about soil desiccation by vegetation would conduce to controlling it, and furthering reasonable management and evolution of vegetation. The feedback response of vegetation to soil desiccation by itself is mainly discussed in this paper. We believe that the phenomenon of soil desiccation by vegetation occurring universally in the Loess Plateau just reflects environmental limitation on vegetation from a peculiar angle. Because artificial forest and grass vegetation is weak in the mechanism of negative feedback regulation compared with natural vegetation, the contradictory show between water use by plant growth and water supply by environment constitutes a so serious threat to stability of artificial forest and grass vegetation that it grows slowly and even declines, and commonly takes marked restraining effect on development of follow- up plant rooting deep after vegetation declination. But on the other hand it is noticeable that follow- up natural vegetation or plant rooting superficially still may succeed to grow well. It is obvious that soil desiccation by vegetation isn ’t favorable for seeking economical goal, but it would uncertainly cause a negative effect on protection of soil from erosion. The stability of artificial forest and grass vegetation should be treated respectively according to their managing goals. The research on naturalizing process of artificial forest and grass vegetation would be a significant proposition related to ecological restoration.
MODIS/EVI time series data were selected to analyze the response of vegetation growth to drought in Sichuan and Chongqing provinces in 2006. To remove the cloud contaminated images, the HANTS algorithm was first used to reconstruct cloud- free images. With the cloud- free images and HANTS algorithm’s components (amplitude and phase), the drought influence to the study region was analyzed combined with the land surface meteorological data. Comparing the performance of the drought year and normal years, the result showed that the processed EVI data could reflect the influence of drought to surface vegetation well, and the amplitude and phase could indicate the spatial distribution of drought.
Based on the retrospection of researches on interaction between urbanization and eco- environment in oasis area, this paper reviewed systematically the relative research progress and prospected the main research directions in the future. Studies showed that the domestic and international scholars succeeded to the history analysis of urbanization and eco- environment relation in oasis areas, paid close attention to the research of oasis urbanization in drainage areas under the condition of water deficiency, and thought much of the research of oasis urbanization and eco- environment interaction mechanism. They generally adopted space analysis technology, complex systematic analysis and mathematics models to appraise the response course of urbanization and eco- environment respectively, paid more attention to differentiating the positive and negative environment effects of urbanization in oasis areas, and strengthened the research on sustainable urbanization patterns in oasis areas. There are still a lot of weak points for recent researches. In the future, the controllability, the close integration with practice, and the cross- disciplinary and systematic dynamic simulation will be the main research trends.
In 2002, the Chinese Central Government put forward the “Rising Strategy of Central China”. The main aim of this strategy is to accelerate economic development in the six provinces located in the Central China, including Shanxi, Henan, Hubei, Hunan, Anhui, and Jiangxi Provinces. With regional economic growth, it is necessary to reconstruct spatial organization of production factors in order to maintain efficient operation of economic activities and long- term competitiveness of the Central China in both domestic and international markets. During the past twenty years, worldwide experiences of industrialization and urbanization indicated that “Extended Metropolitan Regions”or so- called “City- regions”composed of core city and its hinterland are becoming the most important units of regional competition. Through intense and frequent linkages and flows between the center regions and the peripheries, a spatial organism with activeness and high strength gains much concern within academic and administrative fields. The Greater London Metropolitan Region and the Tokyo Metropolitan Region have developed to be the most competitive regions within global market, and they are the most influential financial, commercial and information centers in the world. In China, fast development in the Yangtze River Delta and the Pearl River Delta makes them the gateways combining domestic economy with global markets. Accordingly, in the context of globalization and industrialization process, how to transform the core cities located in central provinces of China into competitive metropolitan regions has great significance to the successful achievement of Rising Strategy of Central China. By employing component analysis and Gravity Model, the centralization degree of each core city is calculated. Furthermore, on the basis of comprehensive analysis, this paper suggests that the Greater Wuhan areas consisting of several adjacent cities can be developed into the most powerful economic growth pole of the Central China, through which regional manufacturing, trade and financial activities in hinterland can be mapped into global production networks. Meanwhile, the provincial capital cities, such as Taiyuan, Zhenzhou, Changsha, Hefei, and Nanchang, can be developed into the primary metropolitan regions and their linkages and flows beyond metropolitan centers will effectively reduce regional disparity and eventually promote the whole regional development to a high level.
‘Integrated function zoning’, a new concept of regional development according to 4 major function- oriented zones, which was advanced initially by the outline of the eleventh fiveyear plan for national economic & social development of the People’s Republic of China, is of operability in regional development planning. And it will have profound influence on spatial organization of social and economic development in China. As a part of advanced research on compilation of ‘Northeast Revitalization Planning’, this paper attempted to provide a draft of integrated function zoning for northeast China. This research constructed and followed a basic framework for integrated function zoning, which is ‘judging overall situation – evaluating enumeration units – compiling a planning’. First of all, it made a comprehensive view of northeast China, including population, GDP, industry, land use, resources and environment. And then, with county- level GIS data and two indicator systems, it evaluated both status quo and prospect of each unit’s development. Finally, based on the findings made by the above two steps, it worked out a draft planning of integrated function zoning for northeast China. The draft is very conducive for compiling ‘Northeast Revitalization Planning’and the 3- step research framework will be of use for reference during other regions’integrated function zoning in the future.
Based on the GIS data o f Beijing’s public facilities, this paper evaluates the accessibility of housing to six types of public facilities, namely educational facility, medical care facility, sports facility, culture facility, shopping facility and parks, in Beijing’s inner city. By calculating the Nearest - Distance Accessibility from newly built residential projects to each category of public facilities as well as employing the traditional Hedonic price model, this paper empirically tested the impact of accessibility to public facilities on housing prices. The results of this paper show that, firstly, in terms of Nearest- Distance Accessibility Criteria, parks, hospitals and gyms are the most easily accessible public facilities while shopping centers, culture facilities and Sports Center (as expressed by ‘Game’in the paper) are among the hardest accessible group. Secondly, when grouping the housing units by location and price level, it turns out that houses within 4th Ring Road as well as higher price groups will enjoy better accessibility to public facilities. Third, there exists positive correlation between the accessibility of housing to key high schools, sports centers, cultural facilities and parks and the housing prices, which implies that the externalities of these public facilities shall have well been capitalized into housing prices.
Based on fractal theory, spatial structure of Urumqi Metropolitan Area is studied; and the economic relation intensities amongst different cities and counties are calculated. In comparison with self- affine fractal characteristics, the spatial distributions of economic relation intensity are analyzed. It is pointed out that the radiation of central city is weak. Combined with degree of industries’similarity, measures of optimization are discussed. It shows that Urumqi, Miquan and Changji are melt into one economic region, and fractal dimension of economic relation intensity is nearly as twice as that of centre in Urumqi. The spatial structure of Metropolitan Area can be further optimized. Based on analysis of optimized plan, two characteristics are found: first of all, economic radiating power and the acceptability of cities around the core region present the law of decaying according to the exponential function with increase of distance. Secondly, gradient diffusion depends on city’s rank and scale. Economic diffusion may bypass the cities whose ranks are low and reach the cities that from the core region but with higher ranks are farther. During the course of economic diffusion, two characteristics co- exist, and the former law is more manifest.
Space- distance- accessibility has become a precondition for the linkage and development of urban regional integration. Currently, the spatial linkage development of metropolitan area and the traffic network construction are obviously asynchronous. The key to solving the contradiction between them is that we should optimize the spatial structure of road network accessibility. In this paper, taking Wuhan city as a case, we construct shortest- distance matrix, introduce temporal and spatial accessibility models, build the evaluation index system of the traffic network with higher hierarchy development, and quantitatively investigate the changes and spatial structure of the urban accessibility of Wuhan metropolitan area. It is found out that: (1) circular city accessibility is quite different in space. This accessibility is closely related with urban traffic location and the city’s economic development level, and the relationship between its spatial structure and urban hierarchy- size is conjugated and synergic. Moreover, different spatial - level nodes form a homocentric layer with Wuhan as its center and demonstrate a “node- spoke”network structure; (2) fast traffic networks (highways, railways etc.) are important impetus to the evolution of urban spatial accessibility; (3) it leads to deceleration of its spatial convergence and forms a significant branded fractionation. Two traffic corridors for urban spatial linkage are formed primarily, which are east- west of Shanghai- Chongqing railway and southnorth of Beijing- Guangzhou railway; and (4) the evolution degree of circular- city traffic network is a little slow as it is in the condition of loop network and the extending potential for traffic network of higher hierarchy is quite great.
As a crossed field of tourism resort study and tourism impact study, tourism resorts not only affect the sustainable development of resorts, but also concern the depth and extent of impact study. Based on the analysis of published papers on resort impact study both home and abroad, such as Tourism Management and Annals of Tourism Research, this paper intends to review and evaluate the progress in study of tourism impact on resorts, especially the tourism impacts brought by enclave resorts. Five aspects of negative impacts of enclave resorts are elaborated in detail: 1) informal sectors being squeezed out by formal sectors in the process of resort development; 2) high economic leakage resulting from import and export; 3) contact and interaction are restricted between residents and resort visitors; 4) poor employment opportunity and manual jobs provided for community residents; and 5) residents lose the control of tourism development due to foreign ownership of facilities. The understanding of studies on enclave resort overseas could help to analyze similar phenomena emerging in the development of resorts in China. By doing so, we can not only get reference of furthering tourism impact study of resorts in China, but also obtain effective solutions to the existing problems of tourism impacts of Chinese resorts.
With the progress of spatial data technologies, the volumes of the spatial data enhance gradually, far exceeding people’s ability to analyze it. Traditional spatial data analysis methods can only carry out simple data analysis, having no way to satisfy people’s need of gaining knowledge. Spatial association rule mining approach, which is used to acquire underlying spatial knowledge from spatial database managing complex, multiple- dimension, large, and flexibility border space spatial data, is a fundamental mission of the spatial data mining. The authors make an annotated review of basic concepts, classification, mining process, current research achievements and so on, especially paying attention to approaches improving mining efficient, mining method based on the uncertain space information and attribute information, visualization of mining results and processes, and negative spatial association rule mining. After deeply analyzing research achievements and existing problems, the authors bring forward the future main development directions of spatial association rule mining.
The increase of urban built- up area is propelled by many factors of society, economy and urban environment. So it is difficult to predict the urban built- up area by traditional methods. Having good performance of nonlinear approximation, artificial neural network (ANN), especially the back propagation algorithm (BP), is applied widely in many predictions and has very satisfactory effects. Principal component analysis(PCA) can reduce the dimensions of data, while maintaining the data characteristic effectively. It is integrated with BP neural network at data input port. By decreasing the number of input neuron, it can enhance the network performance and improve the prediction. Taking Beijing for example, this article establishes a predicting model by using both PCA and BP neural networks, and makes the prediction of urban built- up area for 2005. The model’s learning samples are social, economic and environmental statistics in 1986~2003, and the testing sample is statistics in 2004. The results show that the relative error between the value predicted by the BP neural network based on PCA and the actual value is only 2.8%, and the BP neural network based on PCA has higher precision and better effectiveness than traditional BP neural network.
