越南下龙市不同时期土地利用变化特征

在RS与GIS技术支持下,采用人机交互影像解译方法获取了1973、1988、2003和2014年4期土地利用数据,对越南建国到革新开放、革新开放至施行社会主义市场经济以及社会主义市场经济体制改革至今3个不同发展时期下龙市土地利用方式进行了定量研究,并从土地利用变化速度、程度及转移方向3个方面分析了过去40年该区域土地利用格局及时空变化特征。结果表明：① 建国至今下龙市林地占比缩减了26.3 %,城镇用地与工矿仓储二者占比扩大了4.3倍,耕地和红树林仅占下龙市总面积的3.6%和1.3%,同时养殖用地占比为5.5%。② 建国初期至革新开放时期,下龙市土地利用变化主要是城镇用地和工矿仓储的增建,二者均上升4%左右,空间变化集中于鸿基区,林地减少8.1%,耕地减少3.2%,土地利用总格局未产生明显变化。③ 革新开放至施行社会主义市场经济时期,城镇用地和工矿仓储扩建程度分别为过去15年的3倍和2倍,鸿基和拜寨的城区建设逐渐趋于平衡,林地占比减至52.2%,新地类养殖用地出现,红树林锐减。土地利用空间格局呈现破碎化。④ 施行社会主义市场经济体制到至今,林地锐减至40.0%,土地利用格局由林地占主导地位变为人工地类占主导,耕地和养殖用地分布边缘化。

The Characteristics of Land Use Change during the Different Periods in Halong City

This study was designed to reveal how land use change in Halong City in Vietnam during three different periods from 1973-2014. The land use data in 1973, 1988, 2003 and 2014 based on the remote sensing and land-use thematic maps were established with man-computer interactive image processing methods. Combined with GIS method and analysis model of land use change, we quantitatively analyzed the spatial-temporal change of land use and briefly described the characteristics of land use change in three different historical periods in Halong City since the Founding of Vietnam. The social and historical background is as follows: the first period was from the Founding of Vietnam to the beginning of Vietnam's Renovation and Opening up. The second period was from the beginning of Vietnam's Renovation and Opening up to implementing the policies of the socialist market economy, and the final period was from the beginning of socialist market economy policies up to now. In this paper, we explored the spatial-temporal variation of land use from the rate of land use change, the degree of land use, and the direction of land use transformation. Results suggested that: （1） forests shrank by 26.3% since the Founding of Vietnam. Urban area and Industrial warehouse space expanded 4.3-fold in total. In 2014, farmland and Mangrove accounted for only 3.6% and 1.3%, respectively. In the meantime, Aquaculture accounted for 5.5%. （2） Before the periods of Vietnam's Renovation and Opening up, Urban area and Industrial warehouse space was the mainly change, both increased about 4%, which mainly concentrated in Hòn Gai district. Forests and Farmland decreased 8.1% and 3.2%, respectively. Under the guidance of economic policy "heavy industry, light industry, agriculture", with struggling in economic stagnation, the whole pattern of land use had not obviously change in Halong City. （3） From Vietnam's Renovation and Opening up to implementing the policies of the socialist market economy, Urban area and Industrial warehouse space expand 3-fold and 2-fold than the past 15 years, respectively. Urban construction gradually became gentle in Hòn Gai district and B?i Cháy district. Forests decreased to 52.2%. Aquaculture appeared and it increased about 2.8% in 1988-2003 and caused the decrease of mangroves. With adjusting the guidance of economic policy, the process of urbanization was accelerating in Halong City. The spatial pattern of land use became fragmentation, and urban area construction became more balanced in both of Hòn Gai district and B?i Cháy district. （4） Since implementation of socialist market economy system, forests sharply reduced to 40.0%. Mangrove and Farmland reduced about 3% and 2.5%, respectively. Meanwhile, Urban area, Industrial warehouse space and Aquaculture increased about 8.6%, 4.4% and 2.7%, respectively. The spatial pattern of land use had transformed from forests into artificial construction land. Both sides of coasts on the bay mouth were all covered by urban land. Farmland and Aquaculture were marginalized.