摘要
Vegetation fractional coverage (VFC) is one of the key indicators of vegetation distribution. In the work a measurement-based model was developed to derive total forest VFC (TG) as well as the VFC of trees (T) and shrub-grasses (G) separately in a subtropical forest area in Nanjing, China. Both upward and downward photographs were taken with a digital camera in 72 quadrats (10 m × 10 m each). Fifteen models were established and validated. Models jointly using both T and G performed better than those using the T and G separately. The best model, TG = T + G- 1.134 × T × G- 0.025 (R2 = 0.9115, P < 0.01, root mean squared error = 0.0789), is recommended for application. This model provides a good way to obtain total forest VFC values through taking tree and shrub-grass photos on ground below tree canopy rather than above tree canopy.
Vegetation fractional coverage （VFC） is one of the key indicators of vegetation distribution. In the work a measurementbased model was developed to derive total forest VFC （TG） as well as the VFC of trees （T） and shrub-grasses （G） separately in a subtropical forest area in Nanjing, China. Both upward and downward photographs were taken with a digital camera in 72 quadrats （10 m × 10 m each）. Fifteen models were established and validated. Models jointly using both T and G performed better than those using the T and G separately. The best model, TG = T ＋ G - 1.134× T × G - 0.025 （R2= 0.9115, P 〈 0.01, root mean squared error = 0.0789）, is recommended for application. This model provides a good way to obtain total forest VFC values through taking tree and shrub-grass photos on ground below tree canopy rather than above tree canopy.
基金
Supported by the National Basic Research Program (973 Program) of China (No.2007CB407206)
the National Natural Science Foundation of China (No.40371053)
