Study On The LUCC And Landscape Structure Change Under The Development Of Forestry Industry In Muchuan County By GIS

The analysis methods of landscape structure were introduced when we analyze the LUCC (Land Use and Cover Change) of Muchuan County, and combined with the RS and GIS technique, including the computer automatic classification and the expert knowledge, the LUCC, landscape structure and their transfer character were analyzed quantitatively. The results provided references for understanding the influence extent and rang of the development of regional forestry industry acted on the eco-system. Moreover, it also helped us to identify the trend of change of the eco-system and its internal factors, make suitable eco-system management plans and land use decisions. All conclusions can be summarized as:1. The remote sensing image of Landsat-5 TM in 1990, 2001, 2006 and the forest distribution map in 1999 were used as information source, and the method of supervised classification combined with the expert knowledge were used for the classification. At last, three classification maps of remote sensing images have been got. Their accuracy arrived at 81.42%, 86.52% and 86.10% respectively.2. Methods of spectrum relations (TM2+ TM3＞TM4+ TM5) and critical values (TM4＜60) were used to distill the water boundary, which could obviously reduce the error that water been classified to shadow. As to the building land, the model of "Distilling on the basis of the building and road" were used to correct the results of the supervised classification. Then, the water boundary and the building land were imported to ArcGIS to update the results of supervised classification. These data were converted to format of *.img which meant that the predominance of ArcGIS and ERDAS were combined with the artificial interpretation, a new classification method for automatic classification of remote sensing image was found to enhance the classification accuracy.3. Four period's forest coverage rate in Muchuan county (years of 1990, 1999, 2001 and 2006) were got, arrived at 47.55%, 50.55%, 53.84% and 57.13% respectively.4. The updated vector data were converted to format of *. GRID. Four period's data were analyzed by their area, terrain distribution and landscape structure index. At last, the transfer matrix of land use was got and the main factor, which influenced the land use and landscape change, was found. These results provided rules for recognizing regional landscape structures, planning corresponding eco-system management and land use decisions.5. By calculating the transform matrix of land use, some significant research results were got as below.Years between 1999 and 2001 were the most important period that the farmland converted to forestry land. In this course, large numbers of bamboos were planted, and obviously was the policy of "farm land conversion to forestry land "led the transform course. Among the forestry land transform rate, most were their own transform course. Water and building land have little change. Change of water area influenced mainly by the newly built water-electric station. Change of building land area influenced mainly by the policy of the government's improving city's investment environment, and mainly transformed from farmland and forestry land.6. Statistics of land use type in study region by area and dynamic analysis showed that:Area of farmland decreased gradually with the change of time. By 2006, the area of farmland reached only 42.15% of the total study region. Bamboo land had the great change in the forestry land among years of 1999 and 2001. Area of conifer land and broadleaf land kept steadiness on the whole in 11 years from 1990 to 2001, and after year of 2001, it began to increase. Area of water land and structure land changed small.Dynamic rate of shrubbery land had its biggest values of 14.12% among years of 1990 and 1999; Bamboos land had its biggest values of 44.89% among years of 1999 and 2001; Conifer land had its biggest values of 12.31% among years of 2001 and 2006; Comparing of different land type in different period showed that years among 1999 and 2001 was the most important development period of bamboos economy.7. By calculating the landscape structure index, some significant research results were got as below:Years between 1999 and 2001, large numbers of newly planted bamboos led negative effect to landscape connectivity, and the fragmentized rate of landscape got its maximum which strengthened the infiltration correlated with biological behavior or biological course. It also interpreted that the landscape connectivity been greatly disturbed in this course. After years 2001, large numbers of bamboos converted forest, and diffuse toward every direction, improved the landscape connectivity, the fragmentized had a certain extent decrease.Years between 1999 and 2001, in those area altitudes below 500 meters, the diversity rate and fragmentized rate of patches increased. Considering were mainly farmland in those area, which also meant that the fragmentation of farmland led to the increase of diversity of landscape.In those areas with high altitude, because of their low amount of farm and, the engineering of farmland conversion to forestry land had less influence to farmland. The landscape connectivity got better, the possibility of landscape been divided got small, and the fragmentation of landscape got small. At the same time, it also meant that the influence of human's activities to fragmentation of landscape mainly in those areas with low altitude. 8. By analyzing the district difference of land use, some results were also got below:Years between 1999 and 2001, in those district altitudes below 500 meters, the decrease of field land mainly influenced by development of bamboos industry and some field lands converted to bamboos land. After the engineering of "farmland conversion to forestry land" began to put in practice in year 1999, farmers were afraid of lacking foodstuff and economy income and planted some economic crops under the fertile and thin conifer forest and broadleaf forest which near their residential area. Intense cultivation led the increase of field land. Moreover, years between 1999 and 2001, bamboos land come from farmland were distinguished to farmland for their low coverage rate, and became another important reason of increase of farmland.In those district altitudes between 500 and 1000 meters, the area of field land decreased by 4.30% every year from year 1999 to 2001. On the contrary, area of conifer land and bamboos land increased greatly after year 1999, especially area of bamboos land, increased by 52.02% every year from year 1999 to 2001 and account for 33.42% of low mountain region's total area.District altitudes above 1000 meters had similar change rules in field land's change with district of altitudes between 500 and 1000 meters, but had more significant change from year 1999 to 2001. Bamboos land changed little in this district mainly for the bamboos had turned to utilization stage from forestation stage.9. By analyzing the terrain, some results were also got below:Farmland in study region was mainly sloping field and distributed on slow slope and slant slope. From year 1999 to 2006, area of farmland in this slope range decreased from 10172 hectares to 6799 hectares. This meant sloping field above 25°had 60% out of its primary use after the engineering of "farmland conversion to forestry land" began to put in practice. Conifer land and broadleaf land mainly distributed on slant slope and abrupt land. Increase of conifer land area among year 2001 and 2006 mainly for small influence of human's activity or plantation of conifer trees. On rapid slope and perilous slope, area of broadleaf land decreased with the increase of slope and above slant slope range, area of broadleaf land decreased with the change of time. The reason can be drawn as: under the impulse of forestry economy industry's development, some broadleaf land got inferior position when competed with bamboos land and converted to mixed forest which bamboos got predominance. Shrubbery mainly distributed on slant slope, abrupt slope and rapid slope, and their areas in every slope classes followed the rules: Area of 1999＞Area of 2001＞Area of 1990＞Area of 2006. Bamboos land mainly distributed on slant slope and abrupt slope. Area of bamboos got great development after year 1999 under slope of 25°, especially on slant slope, and the increase extent reached 154%. Water land and structure land were mainly distributed on even slope and slow slope, and had little influence of slope.Area of farmland and bamboos land had the similar slope aspect change rules: Shady Slopes＞half Shady Slopes＞half sunny slopes＞sunny slopes＞flat. Increases of bamboos land area mainly depend on the development of study region's bamboos economy. Shrubbery land and broadleaf land had the same slope aspect change rules: half Shady Slopes＞Shady Slopes＞half sunny slopes＞sunny slopes＞flat. Area of broadleaf land maintained a steady level on the flat land. Conifer land's slope aspect rules was: half Shady Slopes＞half sunny slopes s＞Shady Slope＞sunny slopes＞flat.In a word, years between 1999 and 2001 were Muchuan County's most important period of LUCC and landscape structure change. Development of forestry industry was the direct factor, and the engineering of farmland conversion to forestry land combined with the engineering of natural forest protection were the direct drive force. Biology course was the secondary factor of the landscape dynamic change.