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 ...     

典型红壤丘陵区土地利用空间优化配置

选择具有红壤丘陵区典型特征的江西省泰和县千烟洲为研究区域,在分析当前土地利用结构并进行土地适宜性评价的基础上,依据2000年千烟洲试验站研究数据及农户调查资料,将GIS技术与线性规划模型有效地耦合起来,探讨实现典型红壤丘陵区各种具有特定数量、质量的农用土地资源在空间上最优配置的方法与技术。结果表明,优化方案从现状中牧业短缺的粮、果、林结构转化为较为完善的粮、果、牧、林结构,耕地资源利用结构也由重水轻旱、粮作为主、经作为辅的传统生产模式,转变为粮-经-饲并举的三元优化配置结构;同时,由果业和畜牧业共同支撑的优化方案的经济效益明显优于现状,在经济上更具稳定性和可持续性。     

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.     

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.     

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 agriculture 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 21^st 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.     

基于树木年轮信息的千烟洲人工林碳蓄积的动态分析

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.     

Uncertainty analysis of CO<Subscript>2</Subscript> flux components in subtropical evergreen coniferous plantation

We present an uncertainty analysis of ecological process parameters and CO₂ flux components (R _eco, NEE and gross ecosystem exchange (GEE)) derived from 3 years’ continuous eddy covariance measurements 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 double-exponential (Laplace), rather than a normal (Gaussian) distribution. (2) Different optimization methods 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 R_eco, 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 R_eco, NEE and GEE are 4%−8%, 7%−22% and 2%−4% respectively at annual timescale. Supported by the National Natural Science Foundation of China (Grant No. 30570347), Innovative Research International Partnership Project of the Chinese Academy of Sciences (Grant No. CXTD-Z2005-1) and National Basic Research Program of China (Grant No. 2002CB412502)     

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

ＩＢａｃｋｇｒｏｕｎｄｏｆＥｓｔａｂｌｉｓｈｉｎｇＱｉａｎｙａｎｚｈｏｕＥｘｐｅｒｉｍｅｎｔａｌＳｔａｔｉｏｎＣｈｉｎａｉｓａｃｏｕｎｔｒｙｗｉｔｈａｈｕｇｅｐｏｐｕｌａｔｉｏｎｏｆｌ２ｂｉｌｉｏｎ,ｙｅｔ,ｉｔｉｓｓｔｉｌｉｎｃｒｅａｓｉｎｇｗ...     

基于树木年轮信息的江西千烟洲人工林碳蓄积分析

作者设计和实现了基于树木年轮信息动态估算树木材积生长量模型TGTRing.利用该模型动态估算了中国红壤丘陵典型区千烟洲三种人工林乔木层的生物量和碳蓄积量.结果表明:马尾松的年生物量和碳蓄积量的增长曲线分别在林分年龄17年和18年左右开始出现拐点,湿地松、杉木的年生物量和碳蓄积量则均在林分年龄15年左右开始出现拐点;20年的单位面积生物量和碳蓄积量杉木林最高,分别为171.697 t/hm2和92.29 tc/hm2,其次为湿地松林,分别为147.639 t/hm2(未割脂)和135.743 t/hm2(割脂)、80.18 tc/hm2(未割脂)和73.72tc/hm2(割脂),马尾松林最低,为133.84 t/hm2和73.92 tc/hm2;平均年生物量和碳蓄积量杉木林最高,分别为8.58 t/hm2/yr和4.61 tc/hm2/yr;湿地松林次之,未割脂和割脂湿地松林生物量分别为7.38和6.76 t/hm2/yr、碳蓄积分别为4.01和3.69 tc/hm2/yr;马尾松林最低,分别为6.69 t/hm2/yr和3.70 tc/hm2/yr;到2006年为止,千烟洲马尾松林乔木层总生物量和碳蓄积量分别为3324.43 t、14156.64 tc,杉木林分别1326.97 t、713.27 tc:湿地松林按未割脂算分别为14156.64 t和7688.21 tc,按割脂算分别为13015.97 t和7068.78 tc;千烟洲湿地松人工林因为割脂原因,乔木层总生物量损失1140.67 t,总碳蓄积量损失619.43 tc.     

新时期千烟洲模式研究进展（英文）

20世纪80年代初期,为了解决赣中红壤丘陵区雨季水土流失、旱季农田缺水等问题,中科院千烟洲站李文华院士研究团队提出了著名的“丘上林草丘间塘,河谷滩地果鱼粮”千烟洲模式,进行林–牧–粮、林–果–经、水–陆复合经营等模式的试验示范和推广,解决了生态修复和农业生产中的主要问题。进入新时期以来,在习近平“两山论、生命共同体、生态兴则文明兴”等生态文明思想的引领下,千烟洲模式正在赋予新的内涵。为了减少农药和杜绝抗生素等使用,提升农产品质量,增加农民收入,助力乡村振兴战略,目前千烟洲站在赣中红壤丘陵区重点开展了“林–果–禽、构树–猪–果、草–羊（牛）–肥–果、构树–鱼–鹅、稻–虾”等农业绿色发展模式试验示范,以期为江西赣中革命老区的生态环境保护和农民富裕等生态文明建设贡献千烟洲智慧。