Estimated On The Npp Of Forest With A Modified CASA Model And Developing Of A NPP Query System-a Case Study Of Wawushan Area

Forest Net Primary Productivity (NPP) is one of basic quantitative characteristics in forestecosystems, which not only reflects forest ecosystems' biological characteristics and systemstructure characteristics, but also the comprehensive effects of environmental factors on forestgrowth. NPP is not only the driving force of the carbon cycle, but also the main factor todetermine the carbon source, carbon sinks and the regulation of ecological processes.Based on Geographic Information System (GIS) and Remote Sensing (RS) technology, byuse of the improved CASA model, Landsat TM remote sensing image, meteorological data andcompartment, the NPP of Wawushan forest farm was estimated during2008to2009. By use ofthe relationship of forest biomass and NPP, the results of CASA model was verified in Wawushanforest farm. Combining the advantages of C#friendly human-machine interface and IDLpowerfulraster data analysis capabilities, query system of NPP of Wawushan forest farm wascreated by using Spatial Database Engine and ArcGIS Engine assembly.The results indicated that:(1) CASA model can be used to estimate vegetation NPP well,and can be applied in Wawushan forest farm vegetation net productivity estimation;(2) Thedifferences of the NPP among different vegetation types were marked.According to the high andlow order, the estimated NPP of the vegetation were as follows: Populus euramevicana, Quercusacutissima Carruth, Castanea mollissima Blume, Pinus massoniana Lamb, Pinus elliottii Engelm,shrub, Cunninghamia lanceolata, Taxodium ascendens;(3) The seasonal change of the NPP inWawushan forest farm was marked. The NPP was high in summer, and next high in spring andautumn, and lowest in winter. Mainly due to different season, which has the differentenvironmental factors, and the sun radiation is most important factors among many factors.Innovation of the paper:(1) Using measured forest volume of Wawushan forest farm, the net primary productivitywas calculated by summarised relations between the vegetation volume and biomass, biomassand net primary productivity, and compared with results of CASA model which is a solar energyutilization efficiency model;(2) Using the Geodatabase mode and ArcGIS Engine component techniques, as well asrespective advantages of IDL language and C#language, query system of NPP of Wawushanforest farm was built up. The system was able to query net primary productivity of differentvegetation types in different regions, and was able to scientifically and conveniently manageforest resources.