Estimation Of Phyllostachys Pubescens Forest's Net Primary Productivity Based On Wireless Sensor Networks And Light Use Efficiencymodel

As a kind of important bamboo species with ecological value,economic value and social value,the influence of phyllostachys pubescensforest on the ecosystem has increased year by year.The estimation of phyllostachys pubescens forest's net primary productivity is important to study the spatial distribution characteristics of carbon flux in bamboo forest,and to measure the capacity of phyllostachys pubescence's carbon sink.However,due to the large area and a wide range of distribution of phyllostachys pubescens forest,the current measurement method can only be based on single point measurement,is not representative of the large area of the phyllostachys pubescens forest's net productivity.Model estimation is a widely used method for large area net primary productivity,and with the development of wireless sensor technology,the method of using wireless sensor network to collect model parameters has more and more advantage.In this paper,a wireless sensor network deployment scheme is proposed based on the effective photosynthetic radiation budget model,in this method,continuous data collected from January to September of 2015 in the vicinity of the flux observation tower of in phyllostachys pubescens forest in Anji.Improve the calculation of the parameters of light use efficiency model,andtwo kinds of the calculation method of stress factors(even multiplication and minimum value method)are proposed,with the data of the wireless sensor network collected as the parameter input valueof model.The net primary productivity of bamboo forest was estimated by this method,and the following results were obtained:(1)Based on wireless sensor network data,phyllostachys pubescens forest's net primary productivity from January to September during the year of 2015 is estimated.Make a comparison between the estimation and flux tower measurements,it can be seen that they have a more consistent seasonal trend,reaching a peak in April and August,in line with the physiological characteristics of phyllostachys pubescens forest.But the estimated value of the measured value has a certain degree of underestimate.(2)Two kinds of calculation methods are based on different assumptions on the stress factor K to light use efficiency(even multiplication and minimum value method).Compared theresults ofthe twocalculation methods,the minimum value method has higher coefficient of determination(0.4078)relative to the even multiplication method(0.3132),with better correlation,and the root mean square error and the standard deviation of former were decreased 0.0172mg·m-2·s-1 and(?)0.016mg·m-2·S-1 to the latter,showing that the minimum value methodis of higher accuracy.Therefore,in this study choosing minimum value method is more suitable to the research of phyllostachys pubescensforest's net primary productivity estimation.(3)Basedon theestimation of net primary productivity of phyllostachys pubescens forest to do an interval analysis for 2 daysbetween 2-14 days,it found that as the scale becomes larger,the part data errors will be eliminated,the discrete data will be reduced,andthe estimation accuracy will be improved.For the 2-10 day scales,as the scale increases,the estimation accuracy is improved,andfor10-14 day scales.The result tends to be a constant,it said thateven the scale increased,the improvement on the accuracy is not obvious.Therefore,the 10 day scale is selected as the best estimate scale.