Characteristic analysis of spatio-temporal pattern evolution of land use in Harbin region of Songhuajiang watershed

Based on the data of Landsat TM/ETM+ and field data in 1996 and 2005, land use changes were analyzed by ArcGIS, and the spatio-temporal changes of the land use pattern in Harbin region of Songhuajiang watershed were investigated. The results showed that: the spatial position conversion area of the land use was less than its quantitative change. The area order of land use changes was forestland>cultivated land>grassland>water body>unused land>construction land. The dynamic conversion process of land use was dominated by cultivated land-forestland, grassland-forestland and unused land-forestland, where the interconversion of cultivated land-forestland was at high frequency. The forestland, water area and construction land had high retention rates, and the grassland, unused land and cultivated land had high conversion rates. The forestland-cultivated land and grassland-cultivated land were main land conversion types in the area of 300－600 m above sea level, where the slope is greater than 25°, and overuse grassland and deforestation also existed. Because the research area was the main area of crop for food in Heilongjiang province, the dynamics of the spatio-temporal pattern of land use is helpful to reinforce the protection of land resource and to enforce the agro-forestry policies of reusing farmland for forestland and grassland and forestland. This research is also important in releasing the conflict between human and the fields, and it is meaningful to the sustainable development of land resources in order to keep the ecological balance of the studied region.