| The ecological service provided by multifunctional ecosystem could bring many well-being for people' lives. The 18 th CPC National Congress was emphasized that production capacity of ecological products should be enhanced. Then, the ecological benefit provided by ecosystem was included national economic accounting systems. The dominant role of forest in the land ecosystem, determines its ecosystem function plays an important role to improve ecological environment, and ensure the sustainable development of social economy.In recent 40 years, forest resources in China have taken place significant changes under the impetus of the guidance of forestry policy and forestry ecological engineering. The reveal of the changes of forest resources and forest ecosystem function and the quantitative analysis of the influence of the change of forest resources on forest ecosystem function could provide the decision basis for the protection and development of forest resources, further enhance the public protection consciousness of forest resources, and promote the construction of the national economic accounting system and the ecological civilization system.Based on the ecological big data from forest ecological continuous inventory database and the forest resource bid data from eight National Forest Inventory(NFI) database, the study of the influence of forest resource changes on its ecosystem function was carried out. Using the characteristics of bid data, the change process of forest resource and its ecosystem function in the forty years was analyzed in depth. On this basis, the influence factors of forest ecological system function were analyzed with Path Analisis and Data Envelopment Analysis. The main conclusions were as follows:(1) the changes of forest area, forest volume and forest ecological system function had realized "three growth" in nearly 40 years.The forestland area, arbor forest area, economic forest area, bamboo forest area, shrubbery area and incomplete woodland area increased respectively by 5286.18, 5441.35, 1204.52, 285.63, 2993.22, and 2.5975 million hm2, and open forest land area reduced by 11.6232 million hm2 from the first forest resources inventory to the eighth forest resources inventory in China. To sum up, forestry area increased by 67.14%. At the same time, stand volume appeared successive growth trend, which was an increase of 70.72%(or 6.122 billion m3)from the first forest resources inventory to the eighth forest resources inventory in China. The regulating water amount, fixed soil amount, retaining fertilizer amount, fixed carbon amount, releasing oxygen amount, accumulating nutrient amount, producing anion amount, absorbing pollution gases amount and dust-retention amount increased respectively by 282.772 billion m3/a, 3.704 billion t/a, 184 million t/a, 206 million t/a, 736 million t/a, 11.9028 milliom t/a, 91.46×1025 a year, 19.195 billion kg/a, and 2.853 billion t/afrom the first forest resources inventory to the eighth forest resources inventory in China. Among them, fixed carbon amount, releasing oxygen amount, accumulating nutrient amount, absorbing pollution gases amount increased in multiply, other ecological function growth were all more thanr 70%.(2) The changes of forest area and ecological function were fluctuating in 40 years.The woodland area appeared down during the fourth forest resources inventory, by 4.5404 million hm2; arbor forest area appeared down during the second forest resources inventory, by 9.5065 million hm2; economic forest area appeared down during the seventh forest resources inventory, by 980000 hm2; incomplete woodland area appeared down during the fourth, fifth and eighth forest resources inventory, respectively by 14.98, 252.32 and 4.2188 million hm2.The development trend of forest ecological system function presented reduces first and then increases from the first forest resources inventory to the eighth forest resources inventory. Compared with the first forest resources inventory, the assessment results of the second forest resources inventory presented decrease to different extent, the regulating water amount, fixed soil amount, retaining fertilizer amount, fixed carbon amount, releasing oxygen amount, accumulating nutrient amount, producing anion amount, absorbing pollution gases amount and dust-retention amount decreased respectively by 14.20%, 21.40%, 25.51%, 12.57%, 9.73%, 17.00%, 21.04%,5.73% and 7.59%. Forest ecological system function continued to rise from the second forest resources inventory, followed by the improving of forest resources conditions.The change trend of forest resource and forest ecological system function were not the same under the provincial scale and economical region scale.(3) the main directly and indirect influence facrors of different forest ecological function were different.For water conservation, arbor forest area, economic forest area, bamboo forest area, shrubbery area and annual average rainfall showed that direct positive effect was dominant. And forestry investment and forest volume showed that indirect positive effects was dominant. For soil conservation, arbor forest area, economic forest area, bamboo forest area and annual average temperature showed that direct positive effect was dominant. And shrubbery area, forest volume, forestry investment and annual average rainfall showed that indirect positive effects was dominant. For carbon fixation and oxygen release, economic forest area, bamboo forest area, forestry investment and annual average temperature showed that direct positive effect was dominant. And arbor forest area, shrubbery area, forest volume and annual average rainfall showed that indirect positive effects was dominant. For nutrient accumulation, economic forest area, bamboo forest area and shrubbery area showed that direct positive effect was dominant. And arbor forest area, forest volume, forestry investment and annual average rainfall showed that indirect positive effects was dominant. For atmospheric purication, bamboo forest area and shrubbery area and annual average rainfall showed that direct positive effect was dominant. And arbor forest area, economic forest area, forest volume, forestry investment and annual average temperature showed that indirect positive effect was dominant.(4) The dominant ecological function of different ecological engineering were different.The result calculated by the DEA: the natural forest resources protection project and the 3-north protection project were achieves the effective with technology and scale, but the conversion of cropland to forest program needed increase capital investment and the afforestation area. The dominant ecological function of the natural forest resources protection project were water conservation, soil conservation and carbon fixation and oxygen release. The dominant ecological function of the conversion of cropland to forest program were water conservation and soil conservation. The dominant ecological function of the 3-north protection project was atmospheric purication. |
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