| As the largest carbon pool of terrestrial ecosystem, forest ecosystem plays an important role in the global carbon cycle, because of the regulation of climate and the mitigation of global warming. Nowadays, the effects of climate change on forest ecosystem in Northeast China have become one of the common concerns of production and scientific research departments, at the same time, the region is one of the key areas of China’s natural forest protection project, human activities have a certain impact on the historical dynamic change of forest carbon sink and its temporal and spatial patterns.In this paper, the typical forest vegetation in Northeast China is selected as the research object, CASA model is used to analyze the spatial and temporal changes of the net primary productivity of typical forest vegetation in the study area from1982 to 2012. Based on the results of LUCC Classification, NDVI data and meteorological data, the annual NPP value of typical forest vegetation are simulated so as to assess the carbon sequestration capacity of typical forest vegetation, and explore the response mechanism of between the carbon sequestration and the meteorological factors. The main conclusions are as follows:1)The main land cover of the northeast region are woodland, arable land and grassland, wasteland also has more area, and water and city and built-up have less coverage area. The trend of forest area increased slightly, decreased and then increased slightly, the overall change trend of two types coniferous forest area decreased, while the area of mixed forest and deciduous broad leaved forest increased because of the global warming; the increase of arable land area is mainly due to the increase of population, the situation of grassland degradation is severe, the increase of wasteland area is mainly caused by the increase in the number of barren land, the most significant increase in the area of water was in 2002, mainly due to a sharp increase in precipitation as a result of global El Nino phenomenon, the increase of urban built-up area is mainly due to the improvement of the urbanization level.2)The main land cover of the Heilongjiang is forest, the central part of the province on both sides is arable land, wasteland and water; in Jilin province, the main land cover of the middle and west are cultivated land and wasteland, while the southeast is dominated by mixed forest and deciduous broad-leaved forest ; the main types of land area in west of Liaoning province includes deciduous broad-leaved forest, evergreen coniferous forest, farmland, grassland, there are a number of cultivated land and urban and built-up in the Liaohe plain, deciduous broad-leaved forest and cultivated land are distributed in the eastern part of Liaoning; Greater Khingan Range of eastern Inner Mongolia is the main distribution region of deciduous coniferous forest, and in other areas the main distribution is grassland. From 1982 to 2012, the spatial transfer matrix showed that all kinds of forest types were mainly converted to each other, and the other types of land cover transferred into arable land, while the majority of cultivated land transferred into grassland.3) As for the unit area of carbon sequestration, carbon sequestration for many years from small to large is mixed forest, deciduous broad-leaved forest, evergreen coniferous forest, and deciduous coniferous forest, from the aspect of total amount of carbon, from large to small is deciduous coniferous forest> deciduous broad-leaved forest >mixed forest > evergreen coniferous forest. The minimum value, maximum value, average value and total amount of t annual NPP of the 4 forest types were higher than that before 2000, which was mainly due to global warming.4) The high value area of NPP in the study area is mainly located in the south of Xiaoxing’an Mountains to the main vein of Changbai Mountain in Jilin, with distribution values in the range of 400-600gC/(m2· a), the value of 300-400gC/(m2 · a) is mainly di stributed in Greater Khingan Range and Northern Liaoning, low value areas are mainly distributed in the plain and central and southern Inner Mongolia plateau. Such the distribution features are mainly due to forest type, climate and human disturbance. This spatial distribution of various forest types has been greatly influenced by the regional land use. In addition, the spatial distribution of NPP is affected by climate and interference of human logging.5) In addition to the evergreen coniferous forest, annual average temperature and precipitation and NPP of the other forest types have similar spatial correlation distribution characteristics, for example, the correlation of broad-leaved and mixed forests with temperature and precipitation is not significant from the south of Xiaoxing’an Mountains to the Changbai Mountain, while it is significantly correlated in Greater Khingan Range and Xiaoxing’an Mountains opposite with deciduous coniferous forest ; the correlation between solar radiation and the above forests show a negative correlation in Xiaoxing’ an Mountains. Annual NPP of evergreen coniferous forest and annual solar radiation were mainly negative correlation, the higher the latitude is, the obvious the positive correlation is between precipitation and annual NPP value, except Xiaoxing’an Mountains temperature and evergreen coniferous forest annual NPP showed a strong positive correlation. |
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