China has become the biggest country of carbon emissions, and the size and scale of industrialization and urbanization are unprecedented. The pressure of carbon reduction is increasing day by day with the increasing carbon emissions which have caused more and more international concerns. Carbon reduction should be made possible by both reducing carbon source and increasing carbon sink at the same time. Policies of low carbon development should be different to the regions with obviously different existing carbon source and carbon sink. In this paper, by collecting the data from the forest inventory and some related statistical yearbooks, and by applying the methods of discharge coefficient, stand volume, and carbon sequestration rate in forest and grassland ecosystems at region scale, we made an overall estimation of carbon emissions from energy consumption, and carbon sinks from forest, grassland and arable land at the provincial scale. Then, the regional differences of total carbon emissions, carbon emissions per capita, carbon emissions per unit area, and energy intensity in China are analyzed, and spatial pattern of carbon sink and carbon surplus are discussed. As to the overall carbon emissions at the provincial scale, the carbon emission in Shandong, Shanxi and Hebei is relatively high; the carbon emission in Ningxia, Qinghai and Hainan is relatively low. As to the per capita carbon emission, Inner Mongolia, Shanxi and Ningxia have the largest per capita carbon emission; Jiangxi, Hainan and Guangxi have the lowest. As to the carbon emission per square kilometer, Shanghai has the largest; Qinghai has the lowest. Besides, the provinces with relatively low carbon intensity are Beijing, Guangdong, Shanghai, and Zhejiang, etc. Nationwide, the percentage of forest carbon sink is 53%, and the percentage in Yunnan and Heilongjiang is relatively high. The percentage of grassland carbon sink is 38.51%, mainly concentrated in Inner Mongolia, Qinghai and Xinjiang province. The carbon sinks from arable land focus on the carbon in the process of Maize straw returning to the field, which account for 8.63% of the total carbon sink. The results show that the carbon sinks from arable land in Heilongjiang, Jilin, Henan and Liaoning are higher than the ones in other provinces. Combining the feature of carbon source and carbon sinks of the four economic zones, the key issues in low-carbon development are pointed out. In the future, eastern region should change the development mode and improve energy efficiency through technological innovations. Central region should seize the green development opportunity to promote the low-carbon industry to achieve leapfrog development. Northeast region has high carbon sinks and can actively participate in international carbon trading. By strengthening management, western region should accelerate the technological improvements to improve energy efficiency and the ecological environment, and to enhance the capacity of carbon sinks.

As a regional climate proxy, tree-ring data has the advantages such as high resolution, widespread distribution, long time series, precise dating and so on. Nowadays, reconstruction of historical climate change is becoming a more and more important part in global climate change research. Therefore, Tree-ring data plays a huge role in climate change research. Belonging to the Gymnospermae phylum, pine family, and growing in the temperate, cold temperate, and frigid zones of the Northern Hemisphere, Larix Miller, with regular growth rhythm every year, has a significant position in the research on historical global climate change. Especially in China, there are ten larch species and one variety, all hardy, photophilous, and dominant timber classes, located along the margin of the East Asian Monsoon zone. In this paper, the author has made a comprehensive analysis on recent achievements of main larches in Europe, North America and Asia, combined the development routes, and drawn the conclusions as follows: (1) Among all researches on Larix Miller, tree-ring width dominated, about 72%, followed by maximum latewood density, approximately 16%. In recent years, the research focus began to lean to density from width. (2) Both width and density responded to air temperature better. Thus, they played a more significant role in the temperature research of Northern Hemisphere. (3) Larix decidua Mill. and Larix sibirica Ledeb. contributed to the most achievements, perhaps, because more of them spreaded in the regions of high elevations or latitudes, contrary to Larix himalaica (Cheng et L. K. Fu.) Therefore, the potential of a special species' application to dendroclimatology may be determined by its number and distribution. Among all regions, European received the most fruitful results, 61% or so, tending to large spatial scale and multispecies. Especially after 2000, the discussion on response divergence and stability took the lead. The Alps became the hot area. In North America, density sensitivity has been talked about since 1990s. However, the achievement was rare after 2000, since the researches were mainly related to special physiognomy and ecological events, such as Pristiphora erichsonii invasion, possibly as a result of geographic location and climatic features of North America. In Asia, the climatic reconstruction sprout up in 1990s based on the representative Larix sibirica Ledeb. However, the research became less creative after 2000. Not until recent years, the reconstruction based on maximum latewood density appeared, made by Chinese researchers in the Altai Mountains. As a result, the work in Asia started fast, but developed slowly. In China, the variety of species and climate types made the research quite rich, with Larix olgensis Henry dominating in last century but Larix sibirica Ledeb dominating in the 21st century. Exactly in recent years, some kinds of larches on Tibetan Plateau and Larix principis-rupprechtii Mayr. made a breakthrough and density research appeared, too. On the whole, Chinese researchers did not bring their superiority into full play and the development fell behind other areas relatively. With regard to the development direction of dendroclimatology, it is suggested that the future research in China should focus on spatial "field" and multispecies.

Yield losses caused by heat stress are particularly severe when high temperatures occur concomitantly with the reproductive period of wheat. The stages most sensitive to, and adversely affected by, high temperature stress for wheat yield, so called the thermal sensitivity period, are the ones prior to flowering and during flowering. Temperatures that exceed thresholds throughout the thermal sensitivity period are calculated as the value of heat stress intensity. In addition, we will experience greater climate variability characterized by increased frequency of short periods of extreme climate events, including temperature stress. In this report, PRECIS regional climate modeling system is used to project the future climate in 2001-2090. Based on CERES-Wheat model, experiments on the sensitivity of wheat yield to maximum temperature in thermal sensitivity periods are conducted at six representative stations in China. High temperature stress intensity index is calculated and spatial distribution of heat stress on China's wheat in the future is estimated. The results show that pre-flowering, flowering, and post-flowering stages are sensitive to heat stress, however, with varying degrees of sensitivity. Pre-flowering and anthesis stages are relatively more sensitive to high temperature, compared to post-flowering stage. But it is difficult to design an experiment to simulate extremely high temperatures at varying degrees for a long time period. Short periods of high temperature (single-day high temperature greater than 32℃) in pre-flowering and flowering stages would seriously reduce the wheat yield. The closer the period in which high temperatures occur is to anthesis, the greater the yield losses are. High temperature stress during flowering reduces the ability of pollen to germinate as well as the rate of pollen tube growth. These negative effects disrupt fertilization and reduce grain numbers. However, yield losses during post-flowering stages were mainly due to decreases in grain weight. Early grain filling periods are relatively more sensitive to high temperature stress compared to later periods. CERES-Wheat model shows a limitation in simulating the responses of wheat yields to high temperature during grain filling period. In a thermal sensitivity experiment with the temperature threshold roughly set at 32℃, wheat yields at the six stations decrease to varying degrees. Different wheat cultivars respond to heat stress differentially. The heat stress that will potentially cause substantial losses in the yields of the sensitive cultivars, commonly grown in northwestern China, is expected to increase during the mid-to-late period of this century. The areas susceptible to severe heat stress in China are primarily middle-high altitude areas, namely, Xinjiang, Hetao Region and Northeast China. The wheat cultivars in northern China, especially spring wheat cultivars, are more vulnerable to heat stress. The situation is further aggravated by climate warming, which increases both intensity and extent of heat stress. These adverse effects may be attributed to the factors such as increased frequency of extreme temperature events, climate change enhancing the probability of overlapping temperature peaks, and the timing of flowering. These effects will worsen more strongly in continental regions, such as northern China, than in southern regions, as in the former regions, stronger warming will occur in the future. Temperature increases accelerate wheat development as earlier anthesis and maturity take place. Climate warming will inevitably increase the intensity of heat stress and hence higher risk of wheat yield reduction.

For the numerous science and technology achievements, literature is one of the main documentation tools, which shows origination, developmental process and characteristics, and social values of the scientific researches. In order to promote the development of academic research preferably focusing on eco-compensation, there is an urgent need to comb through recent research progress. In this paper, through review and reflection, summaries and forward looking, we hope to provide a clear view of the direction, key points and existing issues of research on eco-compensation. In this paper, based on the literature during 1987-2012 in "China Knowledge Resource Integrated Database", by using the methods of data statistics, induction and analysis, we first reviewed status and development of eco-compensation research in China from following aspects: literature author, research field, support platform, research method, research region and research level. Then, we analyzed evolvement features of eco-compensation research in China during 1987-2012. (1) In the aspect of literature author, the majority and key group of the researchers are the middle-aged and elderly scientists who possess profound qualification, and the next group of the researchers are in the ones in the phase of career training and development, who had not yet formed a powerful leading author group. (2) In the aspect of research field, there are about 9 hot research fields in China's eco-compensation research, which are eco-compensation mechanism, eco-compensation and ecological construction and environmental protection, eco-compensation measure and pattern, legal system of eco-compensation, eco-compensation and sustainable development, eco-compensation in river basin, standard of eco-compensation, forest eco-compensation, ecosystem service value and eco-compensation. And in the aspect of annual number of publications, we can divide the research fields into 4 types: fast-increase type, slow-increase type, steady type and descend type. (3) In the aspect of support platform, national level scientific fund program and provincial program are the main support platforms. (4) In the aspect of research method, in early stage, qualitative description was the main method. Now, although the quantitative methods such as mathematical model, mathematical statistics, GIS, and questionnaire survey, have been used well, qualitative description is still dominant. (5) In the aspect of research region, most studies are at the province and regional levels, and there are also about 30 types of specific regional zones. (6) In the aspect of research level, the initial researches were mostly on basic principles and their applications, and then turned to technical guidance, decision-making support for policy makers, and other researches concerning the society. Taking together the trend of international research and the current status of domestic research, the future research on eco-compensation should be enhanced in the following aspects. (1) In the aspect of research field, we need not only study the eco-compensation relationship in different zones and different interest groups, and the influences on regional spatial structure, but also study how to protect eco-environmental resources by using eco-compensation techniques. (2) In the aspect of research region, trans-regional studies, trans-provincial studies and cross-border studies are the trends. (3) In the aspect of research method, researchers need to pay more attention to the combination of qualitative and quantitative methods, with qualitative description still being the major approach. At the same time, comprehensive and cross studies on eco-compensation, combining multidisciplinary systems of resources and economic geography, should become the direction of development in the future.