Dynamic analysis on carbon accumulation of a plantation in Qianyanzhou based on tree ring data

The authors developed a model to estimate annual tree growth based on tree-ring data (Abbr. TGTRing model) derived from the trunk at 0.5,1.3 and 2.5 m height. This model was applied to estimate the annual biomass and carbon accumulation of a plantation in Qianyanzhou Red-Soil Hill Comprehensive Development Experimental Station of CAS in Taihe County,Jiangxi Province (Abbr. Qianyanzhou). The results showed that the inflexion points of the biomass and carbon accumulation curves occur at 17 and 18 years of age,respectively,in masson pine,whilst both inflexion points occurred at 15 years in slash pine and Chinese fir. The biomass and carbon accumulation in Chinese fir proved to be greater in the last 20 years than in the other species,with 171.697 t/hm2 and 92.29 tc/hm2,respectively. masson pine,with a biomass of 133.84 t/hm2 and a carbon accumulation of 73.92 tc/hm2 was the lowest whilst slash pine was intermediate with a biomass of 147.639 t/hm2 (unturpentined) and 135.743 t/hm2 (turpentined),and a carbon accumulation of 80.18 tc/hm2 (unturpentined) and 73.72 tc/hm2 (turpentined). In 2006,the total biomass and carbon storage of the tree stratum of masson pine in Qianyanzhou was 3324.43 t and 14,156.64 tc,respectively,whilst the values for Chinese fir were 1326.97 t and 713.27 tc. For slash pine the total biomass was 14,156.64 t (unturpentined) and 13,015.97 t (turpentined),and the total carbon storage was 7 688.21 tc (unturpentined) and 7068.78 tc (turpentined). Following the shaving of slash pine for resin,the total biomass was reduced by 1140.67 t and the total carbon storage fell by 619.43 tc.

An emergy evaluation of the seven years’development of Qianyanzhou ecological experimental station

An emergy (spelled with an “m”) evaluation of Qianyanzhou ecological station was performed in order to study its progress during 7 years' development, using changes of emergy inputs and outputs Emergy indices of Qianyanzhou were evaluated and compared with those from other countries The comparison showed that Qianyanzhou may be developing optimum use of its natural resources

A Study of the Qianyanzhou Mode in a Subtropical Red Soil Hilly Region of China

Qianyanzhou is located in the heart of Jitai Basin in Guanxi town,the county seat of Taihe county in Jiangxi province.Qianyanzhou has a subtropical humid climate and exemplifies the geographic and geomorphologic characteristics of red soil hilly regions in southern China.In the early 1980s,to control soil and water loss and problems with grain yields,Qianyanzhou's researchers proposed an innovative,comprehensive stereoscopic ag- riculture development mode known as the 'Qianyanzhou mode'.This mode included a forest-livestock-food ecosystem,a forest-fruit-economy ecosystem,and a land-water compound stereoscopic system,all located within a watershed.In the Qianyanzhou mode,soil and water loss were completely controlled,thereby promoting environmental conservation and economic development.The state and the society as a whole supported this mode thanks to its far-reaching social impact.In the 21st century,given new societal concerns and continuing economic development,Qianyanzhou mode has been restructured as two ecosystems of forest-fowl and planting-raising circular economies at landscape level,based on an increase in vegetation coverage from 4.3% to more than 80%.These improved modes can significantly enhance the ecosystem,reduce poverty,and to promote the construction of local ecological civilization.This study introduces the Qianyanzhou mode and summarizes its characteristics in different phases.We hope that the information in this study supports improvements to and promotion of the Qianyanzhou mode.We believe the Qianyanzhou mode can play an important role in efforts to modify the agriculture industrial structure,alleviate poverty,and construct ecological civilization.

Advancement of the Qianyanzhou Mode in the New Period

In the early 1980s, to control soil and water loss in the rainy season and problems of water shortages in the dry season in the red soil hilly region of central Jiangxi, the academician team of Li Wenhua from Qianyanzhou Station of the Chinese Academy of Sciences proposed a comprehensive muti-dimensional agriculture development mode known as the “Qianyanzhou Mode”. Since then, models for the forest-livestock-food ecosystem, forest-fruit-economy ecosystem, and land-water compound muti-dimensional system and others have been tested,demonstrated, promoted and used to solve major issues in ecological restoration and agricultural production. With the dawn of the new era, the Qianyanzhou Mode is being given new connotations. In order to reduce the use of pesticides and eliminate the use of antibiotics for improving the quality of agricultural products, increasing farmers’ income, and assisting in strategies for rural vitalization, Qianyanzhou Station is currently focusing on the development of experiments and demonstrations of green agricultural development modes, such as forest-fruit-fowl, hybrid paper mulberry-pig-fruit, grass-sheep(cattle)-fertilizer-fruit, hybrid paper mulberry-fish-goose, paddy-shrimp, and others. The goal of this new effort is to apply the wisdom of Qianyanzhou to the construction of the ecological civilization, including ecological environment protection and the prosperity of farmers in the old revolutionary base areas in central Jiangxi Province.

Surface roughness length dynamic over several different surfaces and its effects on modeling fluxes

Roughness length and zero-plane displacement over three typical surfaces were calculated iteratively by least-square method, which are Yucheng Experimental Station for agriculture surfaces, Qianyanzhou Experimental Station for complex and undulant surfaces, and Changbai Mountains Experimental Station for forest surfaces. On the basis of roughness length dynamic, the effects of roughness length dynamic on fluxes were analyzed with SEBS model. The results indicate that, aerodynamic roughness length changes with vegetation conditions (such as vegetation height, LAI), wind speed, friction velocity and some other factors. In Yucheng and Changbai Mountains Experimental Station, aerodynamic roughness length over the fetch of flux tower changes with vegetation height and LAI obviously, that is, with the increase of LAI, roughness length increases to the peak value firstly, and then decreases. In Qianyanzhou Experimental Station, LAI changes slightly, so the relationship between roughness length and LAI is not obvious. The aerodynamic roughness length of Yucheng and Changbai Mountains Experimental Station changes slightly with wind direction, while aerodynamic roughness length of Qianyanzhou Experimental Station changes obviously with wind direction. The reason for that is the terrain in Yucheng and Changbai Mountains Experimental Station is relatively flat, while in Qianyanzhou Experimental Station the terrain is very undulant and heterogeneous. With the increase of wind speed, aerodynamic roughness length of Yucheng Experimental Station changes slightly, while it decreases obviously in Qianyanzhou Experimental Station and Changbai Mountains Experimental Station. Roughness length dynamic takes great effects on fluxes calculation, and the effects are analyzed by SEBS model. By comparing 1 day averaged roughness length in Yucheng Experimental Station and 5 day averaged roughness length of Qianyanzhou and Changbai Mountains Experimental Station with roughness length parameter chosen by the model, the effects of roughness length dynamic on flux calculation is analyzed. The maximum effect of roughness length dynamic on sensible heat flux is 2.726%, 33.802% and 18.105%, in Yucheng, Qianyanzhou, and Changbai Mountains experimental stations, respectively.

Uncertainty analysis of CO_2 flux components in subtropical evergreen coniferous plantation

We present an uncertainty analysis of ecological process parameters and CO2 flux components (Reco, NEE and gross ecosystem exchange (GEE)) derived from 3 years’ continuous eddy covariance meas-urements of CO2 fluxes at subtropical evergreen coniferous plantation, Qianyanzhou of ChinaFlux. Daily-differencing approach was used to analyze the random error of CO2 fluxes measurements and bootstrapping method was used to quantify the uncertainties of three CO2 flux components. In addition, we evaluated different models and optimization methods in influencing estimation of key parameters and CO2 flux components. The results show that: (1) Random flux error more closely follows a dou-ble-exponential (Laplace), rather than a normal (Gaussian) distribution. (2) Different optimization meth-ods result in different estimates of model parameters. Uncertainties of parameters estimated by the maximum likelihood estimation (MLE) are lower than those derived from ordinary least square method (OLS). (3) The differences between simulated Reco, NEE and GEE derived from MLE and those derived from OLS are 12.18% (176 g C·m-2·a-1), 34.33% (79 g C·m-2·a-1) and 5.4% (92 g C·m-2·a-1). However, for a given parameter optimization method, a temperature-dependent model (T_model) and the models derived from a temperature and water-dependent model (TW_model) are 1.31% (17.8 g C·m-2·a-1), 2.1% (5.7 g C·m-2·a-1), and 0.26% (4.3 g C·m-2·a-1), respectively, which suggested that the optimization methods are more important than the ecological models in influencing uncertainty in estimated carbon fluxes. (4) The relative uncertainty of CO2 flux derived from OLS is higher than that from MLE, and the uncertainty is related to timescale, that is, the larger the timescale, the smaller the uncertainty. The relative uncertainties of Reco, NEE and GEE are 4%-8%, 7%-22% and 2%-4% respectively at annual timescale.