Remote sensing estimation and change analysis of fractional vegetation coverage in Natural Forest Resource Protection Project area

  Objective  The forest resources have been effectively protected and restored with the implement of Natural Forest Resource Protection Project (NFPP) in recent twenty years. In addition to a slight increase in forest coverage, effects of the project are mainly the continuous improvement of forest resource quality. To quantitatively assess the effects of NFPP, the fractional vegetation coverage (FVC) was used as the indicator to demonstrate the forest quality during the first stage (2000−2010) and second stage (2011−2020) of NFPP.

  Method  A modified dimidiate pixel model was proposed based on the new vegetation index composition strategy and the dynamically determination method of the pure vegetation and soil pixels, and time series FVC was generated in the project area. FVC was then validated by forest resource inventory data, Chinese forest ecosystem research network data and airborne hyperspectral data. At last, the spatial and temporal variation of FVC was analyzed in NFPP area of China.

  Result  FVC increased from 0.68 to 0.71 since the implement of the project. Area with increased FVC trend was about 78.22% of the total forest area, while area with decreased FVC trend only accounted for 9.56% of the total forest area.

  Conclusion  Accuracy of the estimated FVC was higher than that of MODIS product. An obviously increasing trend of FVC could be found in the NFPP area, which indicates that the quality of forest is increasing since the implement of NFPP.