| Using two Landsat 5 TM data and a Landsat 8 OLI data from 1993 to 2014(1993and 2001 TM images,2014 OLI image),the border forest change of China and Vietnam in 21 years have been dealt with using Maximum likelihood classification of Envi software and ArcGIS 10.2 software,obtained the explanation map of a land utilization type,carried on the statistical analysis to the three periods,and calculated and analyzed the different types of changes,especially the change of the forest area.The results showed that from 1993 to 2014,the area of forest in China area study has been increasing.In 1993,the forest area in China area study was 16,565.36 km~2.By 2001,the forest areacreased to19,693.47 km~2.By 2014,the increase in forest area was 22,529.77 km~2.In general,the forest area in China area study increased rapidly mainlythe conversion of other types of an area into the forest area.For example,from 1993 to 2001,forest growth in China was mainly the conversion of grassland,cultivated land and bare land into the forest area.From 2001 to 2014,the forest area in China's study area increased to grassland,cultivated land,bare land and burning converted into the forest.The area of forest in Vietnam study area also increased from 1993 to 2014,but it was relatively slow.In 1993,the forest area in the Vietnam study area was 21,355.51 km~2,by 2001,the forest area had increased to 22,999.35 km~2,by 2014,the forest area was22,110.91 km~2.From 1993 to 2001,the increase in forest area in the study area in Vietnam was mainly the conversion of areas of grassland area,cultivated land area and cloud area into the forest area.From 2001 to 2014,the forest area decreased slightly due to the conversion of forest area to another type area such as grass area,cultivated land area,bare land area,burning area and cloud area.From this study,the forest area in China and Vietnam has been increasing from 1993to 2014,the forest area in China has changed rapidly,while the forest area in Vietnam has changed slowly. |
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