Study On The Relationship Between Forest Production Efficiency And Climatic Factors In Liaoheyuan

Using the investigation data and the meteorological material collected from four typical types of forest (Larix principis-rupprechtii Mayr., Poplus davidiana., Betula platyphylla Suk. and Pinus tabulaeformis Carr.) over the past 30 years in liaoheyuan area, this study takes the forest distribution region of North China as study area and make a thorough examination for the relationship between forest productivity and meteorological factors. In order to determine the relationship between average productivity of different forest types and climatic productivity, this research analyze forest biomass, productivity and climatic productivity of liaoheyuan area by means of biomass model, natural sparse model and climatic npp model. Finally, combined with gray relational analysis and the effect of 13 climatic factors on the forest productivity of liaoheyuan area, this study examines association coefficients between different climatic factors and forest productivity in detail. The results were shown as follow:(1)Among the average productivity of the four typical forests in North China, the highest is Larix principis-rupprechtii Mayr. 4.56 t·hm^-2·a^-1 followed by Poplus davidiana. 3.29 t·hm^-2·a^-1 and Betula platyphylla Suk. 2.18 t·hm^-2·a^-1 while the lowest is Pinus tabulaeformis Carr. 1.26 t·hm^-2·a^-1. In the past 30 years, the climatic productivity of liaoheyuan area ranges from 10.02 t·hm^-2·a^-1 to 11.69 t·hm^-2·a^-1 and the average is 10.85 t·hm^-2·a^-1. The lowest point is 10.02 t·hm^-2·a^-1 in 1985 while the highest is 11.69 t·hm^-2·a^-1 in 1998. According to the relation of the productivity of different species of tree and the climatic productivity, it might be concluded that: the productivity of Larix principis-rupprechtii Mayr. and Betula platyphylla Suk. changes the same with the climatic productivity but the productivity of Poplus davidiana. and Pinus tabulaeformis Carr. changes different.(2) Among the average productive efficiency of the four typical forests in liaoheyuan area, the highest is Larix principis-rupprechtii Mayr. 0.42 followed by Poplus davidiana. 0.30 and Betula platyphylla Suk. 0.20 while the lowest is Pinus tabulaeformis Carr. 0.12. Besides the major effect of the mean annual temperatures and the mean annual rainfall, other climatic factors also influence the productive efficiency of those four species of tree. It shows that the productive efficiency of Larix principis-rupprechtii Mayr. effected mostly by the annual sunshine hours and the correlation coefficient is 0.4870; the productive efficiency of Poplus davidiana. and Betula platyphylla Suk. Influenced significantly by the annual frost-free days and the correlation coefficient are 0.4459 and 0.5077; the productive efficiency of Pinus tabulaeformis Carr. effected primarily by the annual surface temperature and the correlation coefficient is 0.3800.