Objective]Based on data obtained from a survey of sample plots of Robinia pseudoacacia and Pinus tabulaeformis plantations in Loess gullies in eastern Gansu,the biomass,carbon concentration,carbon density and patterns of their distribution were analyzed,in order to provide the basic data for estimation of carbon benefits of the plantations in the area.[Method]12-year-old plantations of R. pseudoacacia and P. tabulaeformis in Loess gullies in eastern Gansu were measured through survey of sample plots and actual measurements of biomass,in order to study biomass production of different tree organs,shrub & grass layer and litter layer; carbon storage and its allocation in the layers of tree,shrub,grass,litter and soil.[Result]The mean carbon content in the tree layer of R. pseudoacacia plantation(468.44 g·kg -1)was less than that of P. tabulaeformis(512.77 g·kg -1). The carbon content among various tree organs of R. pseudoacacia varied from 458. 00 g·kg -1 to 496. 96 g·kg -1 ,in an order: stem > branch>leaf>root>bark. The carbon content among various tree organs of P. tabulaeformis ranged from 503. 83 g·kg -1 to 536. 27 g·kg -1 ,in an order: stem > leaf > branch > bark > root. The mean carbon contents of R. pseudoacacia in different layers were:herb (390. 52 g·kg -1 ),shrub (39 8. 72 g·kg -1 ),litter (402. 82 g·kg -1 );The mean carbon contents of P. tabulaeformis in different layers were: herb (413.17 g·kg -1),shrub (436.85 g·kg -1),litter (414.03 g·kg -1). The carbon content in soil layer decreased with soil depth,and the carbon content was higher in surface soil layer (0 -10 cm) than in the other layers;The mean carbon content in 0 -50 cm soil layer of R. pseudoacacia (4. 96 g·kg -1 ) was higher than that of P. tabulaeformis forests (4. 45 g·kg -1). The total biomass of vegetation layer of R. pseudoacacia was 54. 80 t·hm -2 ,of which Arbor layer,herb layer and shrub layer accounted for 95. 88%,2. 65%,1. 46%; The total biomass of vegetation layer of P. tabulaeformis was 24. 37 t·hm -2,of which arbor layer,herb layer,shrub layer accounted respectively for 93. 43%,5. 17% ,and 1. 40%. The biomass and carbon density of the litter layer of R. pseudoacacia was 1. 36 t·hm -2 ,0. 55 t·hm -2 ,accounting for 2. 48%,2. 12% of the vegetation layer;The biomass and carbon density of P. tabulaeformis was 0. 92 t·hm -2 ,0. 39 t·hm -2 ,accounting for 3. 78%,3. 09% of the vegetation layer. The soil carbon density of R. pseudoacacia and P. tabulaeformis were 31. 15 t·hm -2 and 24. 35 t·hm -2 . The carbon density was higher in the soil layer of 0 -10 cm,accounting for 40. 19% and 38. 73%. And the carbon density of their ecosystem were 57. 60 and 37. 38 t·hm -2 ,and their distribution were: soil layer> vegetation> litter layer.[Conclusion]The vegetation biomass of R. pseudoacacia and P. tabulaeformis was in the order: Arbor layer >herb layer>shrub layer,and the stem was the largest of the Arbor layer,accounting for 40. 02%,37. 29%. Results indicated that most ecosystem carbon density of two plantations stored in soil and vegetation, carbon sequestration ability of R. pseudoacacia was higher compared to P. tabulaeformis plantation.%【目的】基于陇东黄土高原沟壑区刺槐人工林和油松人工林样地调查数据，分析其生物量、碳含量、碳密度及其分配规律，为该地区人工林碳效益估算提供基础数据。【方法】以陇东黄土高原沟壑区12年生刺槐人工林和12年生油松人工林为研究对象，采用样地调查与生物量实测的方法，研究刺槐人工林和油松人工林乔木不同器官、灌草层和枯落物层生物量，以及刺槐人工林和油松人工林乔木层、灌草层、枯落物层和土壤层碳储量及其分配特征。【结果】刺槐人工林乔木层平均碳含量(468.44 g·kg －1)低于油松人工林乔木层平均碳含量(512.77 g· kg －1)；刺槐林乔木各器官碳含量为458.00～496.96 g·kg －1，不同器官碳含量表现为干＞枝＞叶＞根＞皮，油松人工林乔木各器官碳含量为503.83～536.27 g·kg －1，不同器官碳含量依表现干＞叶＞枝＞皮＞根；刺槐林草本层、灌木层及枯落物层平均碳含量分别为390.52，398.72和402.82 g·kg －1，油松林草本层、灌木层及枯落物层平均碳含量分别为413.17，436.85和414.03 g·kg －1；随着土壤深度增加，刺槐林和油松林土壤碳含量依次降低，0～10 cm土层土壤含量显著高于10～20，20～30和30～50 cm土层；刺槐林0～50 cm 土层土壤平均碳含量(4.96 g·kg －1)高于油松林(4.45 g·kg －1)；刺槐林植被层生物量为54.80 t·hm －2，乔木层、草本层和灌木层分别占95.88%，2.65%和1.46%；油松林植被层生物量为24.37 t·hm －2，乔木层、草本层和灌木层分别占93.43%，5.17%和1.40%；刺槐林枯落物层生物量和碳密度分别为1.36和0.55 t·hm －2，分别是植被层的2.48%和2.12%，油松林枯落物层生物量和碳密度分别为0.92和0.39 t·hm －2，分别是植被层的3.78%和3.09%；刺槐林和油松林土壤层碳密度分别为31.15和24.35 t·hm －2，0～10 cm土壤层碳密度较高，分别占0～50 cm土层土壤碳密度的40.19%和38.73%；刺槐林植被层生物量(54.80 t·hm －2)高于油松林植被层生物量(24.37 t·hm －2)；刺槐林和油松林生态系统总碳密度分别为57.60和37.38 t·hm －2，且均表现为土壤层＞植被层＞枯落物层。【结论】刺槐林和油松林植被层生物量表现为乔木层＞草本层＞灌木层，乔木层生物量均以树干占比最大，分别为40.02%和37.29%；2种人工林生态系统碳密度主要分布在土壤和植被中，且刺槐人工林生态系统具有较高的固碳能力。
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