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Swidden agriculture is an age-old, widespread but controversial farming practice in Montane Mainland Southeast Asia （MMSEA）. In the uplands of northern Laos, swidden ag- riculture has remained a predominant human-dominated land-use type for centuries. However swidden system has undergone dramatic transformations since the mid-1990s. Debates on changes in swidden cultivation are linked to globally critical issues, such as land use/cover changes （LUCC）, biodiversity loss and environmental degradation. Since the implementation of Reducing Emissions from Deforestation and Forest Degradation （REDD）, much attention has been paid nationally and internationally to swidden agriculture in the tropics. However, knowledge of the explicitly spatial characteristics of swidden agriculture and the conse- quences of these transitions at macroscopic scale is surprisingly scarce. In this study, the intensity of swidden use and fallow forest recovery in northern Laos in 1990, 2002, and 2011 were delineated by means of Landsat Thematic Mapper （TM） and Enhanced Thematic Mapper plus （ETM＋） imagery （30 m） using a decision tree classification approach, followed by an analysis of the spatio-temporal changes in swidden agriculture. Next, annual successive TM/ETM＋ images during 2000-2010 were used to delineate the dynamics of the burning and cropping phase. Subsequently, the burned pixels identified in 2000 were compared respectively with their counterparts in the following years （2001-2011） to investigate temporal trends, land-use frequency, and the swidden cycle using time-series Landsat-based Normalized Difference Vegetation Index （NDVI） data. Finally, as the swidden cycle changed from 1 to 11 years, the fallow vegetation recovery process was studied. The results showed that： （1） from 1990 to 2011, the area of swidden agriculture increased by 54.98%, from 1.54× 10^5 ha to 2.38×10^5 ha in northern Laos. The increased swidden cultivation area was mainly distributed in Luang Prabang and southern Bokeo, whereas the decreased parts were mainly found in Phongsali; （2） swidden agriculture increased mainly at elevations of 500-800 m, 300-500 m, and 800-1000 m and on slopes of 10°-20° and 200-30°. Over 80% of swidden fields were transformed from forests; （3） during 2000-2011, the frequency of swidden use in northern Laos was about two or three times. The interval between two successive utilization of a swidden ranged from one to seven years. Comparison of swidden cycles and the related proportions of swidden farming in 2000, 2003, and 2007 revealed that swidden cycles in most areas were shortened; and （4） there was a significant correlation （0.97） between fallow vegetation recovery and the swidden cycle. The NDVI of regenerated vegetation could approach the average level of forest when the swidden cycle reached 10 years.

Satellite-derived land surface data in 1980 and 2010 were used to represent land use and land cover (LULC) changes caused by the rapid economic development and human activities that have occurred over the past few decades in East Asia and China. The effects of LULC changes on the radiation budget and 2-m surface air temperature (SAT) were explored for the period using the Weather Research and Forecasting (WRF) model. The mosaic approach, which considers the N-most abundant land use types within a model grid cell (here, N = 3) and precisely describes the subgrid-scale LULC changes, was adopted in the integrations. The impacts of LULC changes based on two 36-year integrations showed that SAT generally decreased, with the sole exception being over eastern China, resulting in decreased SAT in China (−0.062 °C) and East Asian land areas (EAL, −0.061 °C). The LULC changes induced changes in albedo, which influenced the radiation budget. The radiative forcings at the top of the atmosphere were −0.56 W m −2 across the whole of China, and −0.50 W m −2 over EAL. Meanwhile, the altered roughness length mainly influenced near-surface wind speeds, large-scale and upward moisture fluxes, latent heat fluxes, and cloud fractions at different altitudes. Though the impacts caused by the LULC changes were generally smaller at regional scales, the values at local scales were much stronger.

The impervious surface area （ISA） at the regional scale is one of the important environmental factors for examining the interaction and mechanism of Land Use/Cover Change （LUCC）-ecosystem processes-climate change under the interactions of urbanization and global environmental change. Timely and accurate extraction of ISA from remotely sensed data at the regional scale is challenging. This study explored the ISA extraction based on MODIS and DMSP-OLS data and the incorporation of China＇s land use/cover data. ISA datasets in Beijing-Tianjin-Tangshan Metropolitan Area （BTTMA） in 2000 and 2008 at a spatial resolution of 250 m were developed, their spatiotemporal changes were analyzed, and their impacts on water quality were then evaluated. The results indicated that ISA in BTTMA increased rapidly along urban fringe, transportation corridors and coastal belt both in intensity and extents from 2000 to 2008. Three cities （Tangshan, Langfang and Qinhuangdao） in Hebei Province had higher ISA growth rates than Beijing due to the pressure of population-resour- ces-environments in the city resulting in increasingly transferring industries to the nearby areas. The dense ISA distribution in BTTMA has serious impacts on water quality in the Haihe River watershed. Meanwhile, the proportion of ISA in sub-watersheds has significantly linear relationships with the densities of river COD and NH3-N.

To understand historical human-induced land use/cover change （LUCC） and its climatic effects, it is essential to reconstruct historical land use/cover changes with explicit spatial information. In this study, based on the historically documented cropland area at county level, we reconstructed the spatially explicit cropland distribution at a cell size of 1 km × 1 km for the Songnen Plain in the late Qing Dynasty （1908 AD）. The reconstructions were carried out using two methods. One method （hereafter, referred to as method 1） allocated the cropland to cells ordered from a high agricultural suitability index （ASI） to a low ASI, but they were all within the domain of potential cropland area. The potential cropland area was created by excluding natural woodland, swamp, water bodies, and mountains from the study area. The other method （hereafter, method II） allocated the cropland to cells in the order from high ASI to low ASI within the domain of cropland area in 1959. This method was based on the hypothesis that the cropland area domain in 1959 resulted from enlargement of the cropland area domain in 1908. We then compared these two reconstructions. We found that the crop- land distributions reconstructed by the two methods exhibit a similar spatial distribution pat- tern. Both reconstructions show that the cropland was mostly found in the southern and eastern parts of the Songnen Plain. The two reconstructions matched each other for about 68% of the total cropland area. By spatially comparing the unmatched cropland cells of the two reconstructions with the settlements for each county, we found that unmatched cropland cells from method I are closer to settlements than those from method I1. This finding suggests that reconstruction using method I may have less bias than reconstruction with method I1.

As an important part of land use/cover change（LUCC）, historical LUCC in long time series attracts much more attention from scholars. Currently, based on the view of combining the overall control of cropland area and ′top-down′ decision-making behaviors, here are two global historical land-use datasets, generally referred as the Sustainability and the Global Environment datasets（SAGE datasets） and History Database of the Global Environment datasets（HYDE datasets）. However, at the regional level, these global datasets have coarse resolutions and inevitable errors. Considering various factors that influenced cropland distribution, including cropland connectivity and the limitation of natural and human factors, this study developed a reconstruction model of historical cropland based on constrained Cellular Automaton（CA） of ′bottom-up′. Then, an available labor force index is used as a proxy for the amount of cropland to inspect and calibrate these spatial patterns. Applied the reconstruction model to Shandong Province, we reconstructed its spatial distribution of cropland during 8 periods. The reconstructed results show that： 1） it is properly suitable for constrained CA to simulate and reconstruct the spatial distribution of cropland in traditional cultivated region of China; 2） compared with ′SAGE datasets′ and ′HYDE datasets′, this study have formed higher-resolution Boolean spatial distribution datasets of historical cropland with a more definitive concept of spatial pattern in terms of fractional format.

The Songnen Plain in Northeast China, one of the key national bases of agricultural production, went through remarkable land use/cover changes in recent years. This study aimed to explore the long-term land use/cover changes and the effects of these changes on the environment. The Landsat-based analysis showed that, during 1986-2000, cropland, built-up land and barren land had increased, among which cropland had the largest increase of 9,198km2 with an increase rate of 7.5%. Woodland, grassland, water body and swampland had decreased correspondingly, among which grassland had the most dramatic decrease of 6,127km2 with a decrease rate of 25.6%. The transition matrix results revealed that grassland, woodland and swampland were the three main land use types converted to cropland. Climate warming created the potential environment for the conversion of grassland and swampland into cropland. Land resources policy made by central and provincial governments of China affected the pattern and inten- sity of land use. Land use/cover changes accompanied by climatic variation brought out a series of environmental con- sequences, such as sand desertification of land, land salinization and alkalinization, grassland degradation, and more frequent floods. Under this circumstance, optimized land use structure and restoration measures are needed.

Human-induced land use/cover change （LUCC） forms an important component of global environmental change. Therefore, it is important to study land use/cover and its change at local, regional and global scales. In this paper we conducted the study of land use change in Northeast China, one of the most important agricultural zones of the nation. From 1986 to 2000, according to the study results obtained from Landsat images, widespread changes in land use/cover took place in the study area. Grassland, marsh, water body and woodland decreased by 9864, 3973, 1367 and 10,052km^2, respectively. By comparison, paddy field, dry farmland, and built-up land expanded by 7339, 17193 and 700km^2, respectively. Those changes bore an interactive relationship with the environment, especially climate change. On the one hand, climate warming created a potential environment for grassland and marsh to be changed to farmland as more crops could thrive in the warmer climate, and for dry farmland to paddy field. On the other hand, the changed surface cover modified the local climate; Those changes, in turn, have adversely influenced the local environment by accelerating land degradation. In terms of socio~economic driving forces, population augment, regional economic development, and national and provincial policies were confirmed as main driving factors for land use change.

A regional climate model （RegCM4） is em- ployed to investigate the impacts of land use/cover change （LUCC） on the climate over the eastern part of Northwest China （ENW） in the periods of 2001 and 2011. The re- sults indicated that the LUCC in ENW, which was char-acterized by desert retreat, reforestation, and farmland expansion, led to significant local changes in surface air temperature （within -0.3℃） and slight regional changes in precipitation （within -15%） in summer. In the desert retreat area, the net absorbed shortwave radiation had a greater influence than evaporative cooling, leading to increases in the daily mean and maximum temperature. Besides, the daily mean and maximum temperatures in- creased in the reforestation area but decreased in the farmland expansion area. As surface albedo showed no significant change in these regions, the temperature in- crease in the reforestation area can be attributed to a decrease in evaporation, while the opposite effect appears to have been the case in the farmland expansion area.

Tourism industry has become an important part of Indian economy, and tourism development has been, however, concentrated to a few areas. Accumulation of tourism activities has reached the critical stage in most of the tourism centers, which pose serious threats to the natural environment. The Bhyundar Valley of Nanda Devi Biosphere Reserve （NDBR） in Uttarakhand State of the Indian Himalaya is a burning example of such problems. Land use/cover changes, deforestation and accumulation of garbage are some of the negative impacts of unregulated tourism in the valley. Unsustainable activities of tourists and villagers in the valley make such problems very severe. To deal with the ongoing problems and ensure community involvement in tourism management and environmental conservation, the Biosphere Reserve Authority introduced ecotourism in the form of Eco Development Committees （EDCs） in the Bhyundar Valley. Study reveals that many problems associated with tourism have been minimized to some extent with the help of EDCs but few are still prevailing in valley. However, the existing attempts to conserve the valley from the negative effects of tourism are inadequate and modifications are needed in the current initiatives.

The spatialization of population of counties in China is significant.Fistly,we can gain the estimated val-ues of population density adaptive to different kinds of regions.Secondly,we can integrate effectively population data with other data including natural resources,environment,society and economy,build 1km GRIDs of natural resources re-serves per person,population density and other economic and environmental data,which are necessary to the national manage-ment and macro adjustment and control of natural resources and dynamic monitoring of population.In order to establish population information system serving national decision-making,three steps ought to be followed:1)establishing complete geographical spatial data foundation infrastructure including the establishment of electric map of residence with high resolu-tion using topographical map with large scale and high resolution satellite remote sensing data,the determination of at-tribute information of housing and office buildings,and creating complete set of attribute database and rapid data update-ing;2) establishing complete census systems including improving the transformation efficiency from census data to digital database and strengthening the link of census database and geographical spatial database,meanwhile,the government should attach great importance to the establishment and integration o population migration database;3)considering there is no GIS software specially seving the analysis and management of population data,a practical approach is to add spe-cial modules to present software system,which works as a bring actualizing the digitization and spatialization of popula-tion geography research.