Dynamic Monitoring Research Of Qiaobei Woodland Change Based On "3S" Technology

Woodland is the most important forest resource.Woodland alteration survey is benefit to strengthen the management of forest land protection and achieve timely monitoring of woodland.Besides,it is also a important measure to updating the"one map of forest land"which is the fundamental of sticking the forest ecological red line and strengthening forest supervision.This study adopted"3S"technology and the result of 2014 woodland alteration combine with some other data including remote sensing image,forest land protection and utilization planning,general land use planning to correct the status database and define the scope of forest land properly.The objectives of this study were to defining the boundaries of forest management actives(such as forestation,deforestation and updating)and non-forest management actives.What’s more,images and forest land database obtained in 2016 and 2014 were adopted to determine which compartment has become building land or agricultural land and generated the remote sensing interpretation results based on county level.Finally,forest status database and forest land change database were generated based on 2014 forest change survey map,the results of imagery interpretation and manual survey results.These database were necessary to analysis the status quo and changes of forest resources,the reason of forest land change or understand the spatial and temporal characteristic of forest land.The results showed that:(1)The status of woodland resource:QiaoBei forest administration is state-owned forest with 274389.76hm~2.The area of forest land is about 215377.77hm~2 accounted for 78.49%of the total woodland area;The forest coverage rate is 76.31%,which is 0.08%lower than that in the early stage.According to the origin:the natural forest area is 251430.78hm~2,occupying92.80%of the total area and the area of plantation is 19513.66hm~2,accounting for 7.20%.According to forest classification,the area of public welfare woodland is 273150.55hm~2,which accounts for 99.55%of woodland area and commercial forest area is 1239.21hm~2,accounting for 0.45%of forest land area.According to forest protection grade:first class protection forest land 30752.53hm~2,accounting for 11.21%of the overall forest area;second class protection forest land about 158706.37hm~2,accounting for 57.84%of the overall forest area;Class III protection forest land 83691.65hm~2,accounting for 30.50%of the total forest land area;Class IV protection forest land 1239.21hm~2,accounting for 0.45%of the total forest land area.(2)The alternation of forestland:the total amount of alternation sub compartment in forest lands at Qiaobei Forestry administration was 1381.The area of woodland decreased436.19hm~2;forest land decreased 229.08hm~2.Open woodland decreased 13.35hm~2.shrub land decreased 239.07hm~2,and immature forest decreased 48.76hm~2.Nursery land has no change.No stand woodland increase about 110.34hm~2.Suitable forest land decreased 15.9hm~2.The reasons of forest land area change as follows:The area of forestland change in 2014-2016years of the QiaoBei Forestry administration is 1799.69hm~2.The area of forest land change caused by the planning adjustment is 1168.92hm~2,accounting for 64.95%.The change area caused by the investigation factors is 289.73hm~2,accounting for 16.10%.The change area caused by the construction project is 166.32hm~2,accounting for 9.2.4%.The change area caused by deforestation was 126.94hm~2,which accounted for 7.05%.The area of the construction project without permission was 35.55hm~2 and account for 1.98%.The alternate area caused by reforestation was 12.23hm~2 and account for 0.68%.(3)The spatial and temporal analysis showed that the change area of forest land in 2014was 11881.67hm~2.The area of woodland,sparse woodland,shrub and immature forest were all in a state of increase.While the forest land,nursery land and no stand woodland were in reduced condition.In 2016,the changed area of woodland was 1799.69hm~2.The area of forest land,open woodland shrub land,immature forest and suitable forest were reduced.The area of no stand woodland was increased.