Spatial distribution measurement of leaf area index in flux contributing source of eddy covariance flux tower

Cyclic sampling design was used to investigate leaf area index(LAI) in flux contributing source of eddy covariance flux tower swamp ecosystems of Haibei.Depending on measured values of LAI and geographical information of GPS sample positions,spatial distribution map of LAI in flux contributing source was mapped out using spatial interpolation method.A new method of measuring leaf area based on digital photography and geographic information system technology was advanced.It is a quick and high-precision method,well adaptable to a diversity of vegetation leaf.In the GRID environment of ArcGIS,original format of digital image of the leaf was transformed and the leaf image resolution made finer by using re-sampling functions.Leaf area was then extracted from the digital leaf image using self-ordained chroma diagnosis program in arc -macro language(AML).The results suggest that leaf area values computed by the method match well with measured leaf areas by instrumental methods(LI-3000A),as their linear regression determination coefficient (R²)turn out to be 0.98.It demonstrates that the accuracy of leaf area measurement by the method meets practical leaf area measurement requirements.