热带山地雨林生态系统水文化学循环规律的研究

根据５ａ定位观测，对尖峰岭热带山地雨林更新林生态系统的水文化学循环规律数据分析表明，年均降雨量为２６６８．３ｍｍ，其中总径流量占４６．７％，蒸散量５３．３％，冠层留量１４．０％。Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ的年均降雨输入量为７８．４ｋｇ（ｈｍ＾２．ａ），总径流输出５６．７ｋｇ／（ｈｍ＾２．ａ），净积累２１．６ｋｇ／（ｈｇｍ＾２．ａ），Ｓｉ，有机Ｃ、Ａｌ、Ｍｎ的年均降雨输入量为２５．０ｋｇ（ｈｍ＾２．ａ）     

海南岛清澜港红树林垂直结构与演变动态规律*

清澜港的红树林在保护较好的条件下具有乔灌两层，乔木层高４～８ｍ，灌木层高０．４～１．２ｍ。上层立木地上部分生物量垂直分布随树体部位增高而减少，０～２ｍ占５０％，２～４ｍ占４０．３％，４ｍ以上占９．７％。乔木群落被破坏后，面积锐减，２７ａ减少１６１１ｈｍ２，且形成仅有单层结构的灌丛，其生物量和生产力很低，分别为９．６～１４．３ｔ／ｈｍ２和１．１～２．０ｔ／（ｈｍ２·ａ）。本项研究测定了木榄林的生物量和净生产量分别为９１．５ｔ／ｈｍ２和４．７ｔ／（ｈｍ２·ａ），预测以后第６年的生物量和年净生产量将是３５０．７ｔ／ｈｍ２和１３．５ｔ／（ｈｍ２·ａ），为红树林造林和经营提供了理论依据。     

不同龄组马尾松人工林生物量及生产力的研究

对桂中丘陵区不同龄组马尾松人工林的生物量及生产力进行了研究．结果表明：幼龄林（８ａ生）生物量为３２．０ｔ／ｈｍ２，中龄林（１４ａ生〕为１０８．０ｔ／ｈｍ２、近熟林（２３ａ生）为１８６．６ｔ／ｈｍ２，成熟林（３８ａ生）为１９７．４ｔ／ｈｍ２；林分平均净生产量分别为４．００ｔ／ｈｍ２·ａ．７．７１ｔ／ｈｍ２·ａ、８．１２ｔ／ｈｍ２·ａ和５．８０ｔ／ｈｍ２·ａ．     

蓝桉不同整地方式造林水土流失监测初报

采用径流小区定位观测法，对保山砂页岩发育的山地红壤进行不同整地方式营造蓝桉林，经过三年的监测研究表明：未整地自然土壤侵蚀量达１．６５７～１．４０２ｔ／ｈｍ２·ａ，有机质流失量达８０．４８３～６８．１１３ｋｇ／ｈｍ２·ａ，土壤肥力退化显著；撩壕整地及挖塘整地造林当年土壤侵蚀量分别达３．３６６ｔ／ｈｍ２·ａ及２．４６４ｔ／ｈｍ２·ａ，均属轻度侵蚀级，第二年土壤侵蚀量为０．５９２ｔ／ｈｍ２·ａ及０．３６７ｔ／ｈｍ２·ａ为微度侵蚀。有机质流失量为７５．８１１ｋｇ／ｈｍ２·ａ及４７．１２２ｋｇ／ｈｍ２·ａ。随着桉树幼林生长，林地覆盖度和地表稳定程度增加，土壤侵蚀急剧下降。     

哀牢山木果石栎林降雨过程中的养分循环

本文以云南哀牢山国家级自然保护区中山湿性常绿阔叶林的主要森林类型－木果石栎林为研究对象，分析了大气降雨对该生态系统地养分循环。结果表明，以大气降雨，穿透雨和树木干流为养分输入，以地表迳流和土壤渗漏为养分输出的养分循环过程中Ｎ、Ｐ、Ｋ，Ｃａ等分别增加了１５．９４１ｋｇ／ｈｍ＾２．ａ，０．３５３ｋｇ／ｈｍ＾２．ａ，３．８３ｋｇ／ｈｍ＾２．ａ和１．２０１ｋｇ／ｈｍ＾２．ａ而Ｍｇ减少了０．６５４ｋｇ／ｈｍ     

哀牢山木果石栎林降雨过程中的养分循环

本文以云南哀牢山国家级自然保护区中山湿性常绿阔叶林的主要森林类型——木果石栎林为研究对象，分析了大气降雨对该生态系统的养分循环。结果表明，以大气降雨、穿透雨和树木干流为养分输入，以地表迳流和土壤渗漏为养分输出的养分循环过程中，Ｎ、Ｐ、Ｋ、Ｃａ等分别增加了１５．９４１ｋｇ／ｈｍ~２·ａ，０．３５３ｋｇ／ｈｍ~２·ａ，３．８３ｋｇ／ｈｍ２·ａ和１．２０１ｋｇ／ｈｍ~２·ａ，而Ｍｇ减少了０．６５４ｋｇ／ｈｍ~２·ａ。     

梯形整地桉松混交林模式的水文生态功能

１９８２～１９９１年，对广西宜山县庆远林场不同整地方式及其不同植被类型的水文要素进行对比观测研究。结果表明，梯形整地桉松混交林模式具有显著的涵养水源、保持水土功能；与其他植被类型相比较，具有以下几点显著的差异：ａ．森林群落冠层的年截留水量为２３０．１ｍｍ，占降水量的１８．４％，比其他森林群落增加截留量１２．０％～５７．１％。ｂ．枯枝落叶层贮量及其最大持水量分别为７．７ｔ／ｈｍ２和２３．０ｔ／ｈｍ２，是其他植被类型的１．４～６．４倍。ｃ．土壤层的最大贮水量为５１１．５ｍｍ，比其他植被类型增加贮水６．６％～１１．８％。ｄ．林地水、土流失量分别为４．６ｍ３／（ｈｍ２·ａ）和０．６３ｋｇ／（ｈｍ２·ａ），比其他植被类型减少７９．０％～９７．９％。     

蜡蚧轮枝菌防治湿地松粉蚧的技术研究

蜡蚧轮枝菌用湿地松粉蚧连续复壮２～３次后，用其防治湿地松粉蚧，杀虫效果可提高１２．３％以上，筛选出轮枝菌复合剂的最优配方为轮枝菌０．３亿／ｍｌ加机油乳剂１：２８．６（机油乳剂：水）及适量增效剂、悬浮剂及轮枝菌０．２５亿／ｍｌ加机油乳剂１：８０及增效剂。悬浮剂，它们室内杀虫效果分别为９２．８％和８３．５％。林间采用轮枝菌１５１亿／ｈｍ２加机油乳剂０．７５ｋｇ／ｈｍ２和轮枝菌１５万亿／ｈｍ２加机油乳剂３．７５ｋｇ／ｈｍ２，喷洒量为１０ｋｇ／ｈｍ２，越冬代粉蚧（成虫）的死亡率分别为４８．５％和７１．２％，第一代粉蚧（若虫、成虫）的死亡率分别为９９．３％和９２．７％。越冬后期喷菌，第一代的虫口密度比未喷菌区下降５２．７％；采用液、固双相发酵工艺生产的轮枝菌含孢量达５５亿／ｇ，比前人用高梁、小米作培养基密封培养的产孢量（４．１亿／ｇ）提高了１２．４倍，成本为３．３８元／ｋｇ，此工艺流程可以推广应用。     

内蒙古磴口引黄灌溉对土壤影响的研究

内蒙古磴口河套地区４ａ灌溉试验表明：（１）采用目前生产上的１５０００－２２５００ｍ＾３／（ｈｍ＾２．ａ）灌溉量，使土壤表层的含盐量由灌溉前的０．５ｇ／ｋｇ上升到１．０ｇ／ｋｇ以上。（２）按合理灌水定额公式计算，年灌溉量以７５００ｍ＾３／ｈｍ＾２为宜；最佳含水率下限１９．９９％；在灌水期地下水位为１．９７－３．０２ｍ，变幅１ｍ左右（３）年灌水次数应控制在８－１２次。     

杉木幼林生态系统N,P,K循环及模拟研究

在尤溪杉木人工林生态站７年定位观测基础上，进行杉木幼林生态系统养分循环研究，建立了养分循环的分室模型。结果表明：７年生杉木幼林生态系统Ｎ、Ｐ、Ｋ贮量分别为；７３０８．４６、２０２２．９６、１３０２９０．１４ｋｇ／ｎｍ２，其中９９．７３％存在于土壤分室中。杉木幼林Ｎ、Ｐ、Ｋ年吸收量５２．２０ｋｇ／ｈｍ２，年存留量２２．６２ｋｇ／ｈｍ２，年归还量２９．５８ｋｇ／ｈｍ２，系统每年通过水文学途径获得Ｎ、Ｐ、Ｋ为１５．９２ｋｇ／ｈｍ２，径流输出９．２３ｋｇ／ｈｍ２，系统中年净积累６．６９ｋｇ／ｈｍ２。同时通过计算模拟，定量地描述了０—１０年内系统Ｎ、Ｐ、Ｋ在各分室的运转状态及施肥效果，并计算了Ｎ、Ｐ、Ｋ达到稳定状态时的平衡点。     

Role of canopy interception on water and nutrient cycling in Chinese fir plantation ecosystem

The role of canopy interception on nutrient cycling in Chinese fir plantation ecosystem was studied on the basis of the position data during four years. Results indicate that the average canopy interception amount was 267.0 mm/year. Canopy interception play a significant role in water cycle and nutrient cycle processes in ecosystem, and was an important part of evaporation from the Chinese fir plantation ecosystem, being up to 27.2%. The evaporation from the canopy interception was an important way of water output from ecosystem, up to 19.9%. The flush-eluviation of branches and leaves caused by canopy interception brought nutrient input of 143.629 kg/(hm² · year), which was 117.2% of the input 63.924 kg/(hm² · year) from the atmospheric precipitation. The decreased amount of 80.1 mm precipitation input caused by canopy interception reduced the amount of rainfall into the stand surface and infiltration into the soil, reduced the output with runoff and drainage, and decreased nutrient loss through output water. Therefore, the additional preserve of nutrient by canopy interception was 8.664 kg/(hm² · year). __________ Translated from Scientia Silvae Sinicae, 2006, 42(12): 1–5 [译自: 林业科学]     

Relationship and its ecological significance between plant species diversity and ecosystem function of soil conservation in semi-humid evergreen forests, Yunnan Province, China

In recent years, the relationship between biodiversity and ecosystem stability, productivity, and other ecosystem functions has been extensively studied by using theoretical approaches, experimental investigations, and observations in natural ecosystems; however, results are controversial. For example, simple systems were more stable than complex systems in theoretical studies, and higher productivity was observed in human-made ecosystems with poorer species composition, etc. The role of biodiversity in the ecosystem, such as its influence on sustainability, stability, and productivity, is still not understood. Because accelerated soil-erosion in various ecosystems has caused a decrease of primary productivity, a logical way used in the study of the relationship between biodiversity and ecosystem function can be used to study the relationship between plant species diversity and soil conservation. In addition, biodiversity is a product of evolutionary history, and soil erosion is a key factor controlling the evolution of modern environment on the surface of the Earth. A study on the relationship between biodiversity and soil-erosion processes could help us understand the environmental evolution of Earth. Fifteen 10 m × 40 m standard runoff plots were established to measure surface runoff, soil erosion, and total P loss in different secondary communities of semi-humid evergreen broad-leaved forests that varied in composition, diversity, and level of disturbance and soil erosion. The following five communities were studied: AEI (Ass. Elsholtzia fruticosa + Imperata cylindrical), APMO (Ass. Pinus yunnanensis + Myrsine africana + Oplismenus compsitus), APLO (Ass. Pinus yunnanensis + Lithocarpus confines + Oplismenus compsitus), AEME (Ass. Eucalyptus smith + Myrsine africana + Eupatorium adenophorum), and ACKV (Ass. Cyclobalanopsis glaucoides + Keteleeria evelyniana + Viola duelouxii). Tree density, the diameter of the tree at breast height, and the hygroscopic volume of plant leaves were determined in each plot. Results indicated that surface runoff, soil erosion, and total P loss decreased as a power function with increase in plant species diversity. Their average values for three years were 960.20 m³/(hm² · year), 11.4 t/(hm² · year), and 127.69 kg/(hm² · year) in the plot with the lowest species diversity, and 75.55 m³/(hm² · year), 0.28 t/(hm² · year), and 4.71 kg/(hm² · year) in the plot with the highest species diversity, 12, 50, and 25 times respectively lower compared with the lowest species diversity plots. The coefficients of variation of surface runoff, soil erosion, and total P loss also followed a power function with the increase of plant species diversity, and were 287.6, 534.21, and 315.47 respectively in the lowest species diversity plot and 57.93, 187.94, and 59.2 in the highest species diversity plot. Enhanced soil conservation maintained greater stability with increased plant species diversity. Plant individual density increased linearly and the canopy density and cross section at breast height increased logarithmically with the increase of plant species diversity. The hydrological function enhanced as the plant species diversity increased. There were obviously relationships between plant species diversity and rainfall interception, coverage, and plant individual density, which was related to soil conservation functions in the five forest communities. The complex relationships between plant species diversity and the above-mentioned ecological processes indicated that plant species diversity was an important factor influencing the interception of rainfall, reducing soil erosion and enhancing the stability of soil conservation, but its mechanism is not known. This experiment showed that plant species diversity promoted soil and nutrient conservation and ultimately lead to the increase of the primary productivity of the ecosystem, and was thus a good way to study the relationship between biodiversity and ecosystem stability. Rainfall interception could be assessed easily using the hygroscopic volume of plant leaves. Because there were strong correlations between plant species diversity and soil conservation functions, the patterns of plant species diversity will show a certain level of predictability on the interactions of life systems with surface processes of the Earth. __________ Translated from Journal of Plant Ecology, 2006, 30(3): 392–403 [译自: 植物生态学报     

Transfer characteristics of nutrient elements through hydrological process of a Pinus tabulaeformis stand in the West Mountain of Beijing

Forest precipitation chemistry is a major issue in forest hydrology and forest ecology. Chemical contents in precipitation change significantly when different kinds of external chemical materials are added, removed, translocated and transformed to or in the forest ecosystem along with precipitation. The chemistry of precipitation was monitored and analyzed in a 31-year-old Pinus tabulaeformis forest in the West Mountain of Beijing. Movement patterns of nutrient elements in hydrological processes can be discovered by studying this monitored data. Also, the information is useful for diagnosing the function of ecosystems and evaluating the impact of the environment on the ecosystem. Samples of rainfall, throughfall and stemflow were collected on the site. In the lab, Ca²⁺ and Mg²⁺ were analyzed by flame atomic absorption and K⁺ and Na⁺ by flame emission. NH₄ ⁺-N was analyzed by indophenol blue colorimetry and NO₃ ⁻-N was analyzed by phenoldisulfonic acid colorimetry. The results showed that: 1) The concentration gradient of nutrient elements clearly changed except for Na⁺. The nutrients in stemflow were significantly higher than those of throughfall and rainfall as the precipitation passed through the P. tabulaeformis forest. The monthly patterns showed distinct differentiation. There are indications that a large amount of nutrients was leached from the canopy, which is a critical function of intra-ecosystem nutrient cycling to improve the efficiency of nutrient use. 2) The concentrations of NO₃ ⁻-N and K⁺ changed more than those of the other nutrient elements. The concentration of NO₃ ⁻-N in throughfall and stemflow was 4.4 times and 9.9 times higher than those in rainfall, respectively. The concentration of K⁺ in throughfall and stemflow was 4.1 times and 8.1 times higher than those in rainfall, respectively. 3) The leaching of nutrient elements from the stand was an important aspect of nutrient return to the P. tabulaeformis forest, which returned a total amount of nutrient of 54.1 kg/hm², with the contribution of Ca²⁺ and K⁺ much greater than that of other elements. Also, K⁺ was the most active element in leaching intensity. 4) Nutrient input through precipitation was the main source in the West Mountain of Beijing and the amount of nutrient added was 66.4 kg/hm², of which Ca²⁺ and N contributed much more than the other nutrient elements. When precipitation passes through the P. tabulaeformis forest, 121 kg/hm² of nutrient is added to the forest floor. Ca²⁺ recorded the greatest nutrient increase, with 61.2 kg/hm², followed by N (NH₄ ⁺-N and NO₃ ⁻-N), K⁺ and Mg²⁺, with 31.3 and 16.5, and 8.11 kg/hm², respectively. The least was Na⁺, 3.34 kg/hm². Translated from Acta Ecologica Sinica, 2006, 26(7): 2,101–2,107 [译自: 生态学报]     

杉木人工林水土流失及养分损耗研究

１９８４～１９９６年在江西分宜县中国林科院亚热带林业实验中心的３个林场,分别对杉木人工林幼龄林、中龄林及近熟林进行了８组水土保持及养分循环方面多点的试验观测,对杉木人工林水土流失及养分损耗作了研究。结果表明,杉木人工林水土流失以幼林阶段为最大,其次中龄林阶段,最小是近熟林阶段。幼龄林地表迳流量为５４６．０ｍ＾３．ｈｍ＾－２,土壤侵蚀总量为１０５０．０ｋｇ．ｈｍ＾－２,土壤侵蚀量尤为明显;中龄林地表迳流量为５０６．９８ｍ＾３．ｈｍ＾－２;而近熟林地表迳流量为４７７．２５ｍ＾３．ｈｍ＾－２,土壤侵蚀量可略而不计。幼龄林流失有机质５０．０４９ｋｇ．ｈｍ＾－２,养分为３１．５０８ｋｇ．ｈｍ＾－２;中龄林流失有机质为６．０８０ｋｇ．ｈｍ＾－２,养分流失量为２．０９６ｋｇ．ｈｍ＾－２,而近熟林养分流失量为１０．７８４ｋｇ．     

Carbon sink in Phoebe bournei artificial forest ecosystem

Biomass, carbon content, carbon storage and spatial distribution in the 32-year-old Phoebe bournei artificial forest were measured. The mean biomass of the forest stand was 174.33 t/hm², among which the arbor layer was 166.73 t/hm², which accounted for 95.6%. Carbon contents of stems, barks, branches, leaves, root, shrub layer, herb layer, lichen layer and litter layer were 0.5769 g C/g, 0.4654 g C/g, 0.5232 g C/g, 0.4958 g C/g, 0.4931 g C/g, 0.4989 g C/g, 0.4733 g C/g, 0.4143 g C/g, 0.3882 g C/g, respectively. The mean carbon content of soil was 0.0139 g C/g, which reduced gradually along with soil depth. Total carbon storage of the P. bournei stand ecosystem was 227.59 t/hm², among which the arbor layer accounted for 40.13% (91.33 t/hm²), the shrub layer accounted for 0.17% (0.38 t/hm²), the herb layer accounted for 0.76% (1.71 t/hm²), the lichen layer accounted for 0.28% (0.63 t/hm²), and the litter layer accounted for 0.29% (0.66 t/hm²). Carbon content (0–80 cm) of the forest soil was 58.40% (132.88 t/hm²). Spatial distribution ranking of carbon storage was: soil layer (0–80 cm) > arbor layer > herb layer > litter layer > lichen layer > shrub layer. Net production of the forest stand was 8.5706 t/(hm²·a), in which the arbor layer was 6.6691 t/(hm²·a), and it accounted for 77.82%. Net annual carbon sequestration of the P. bournei stand was 4.2536 t/(hm²·a), and the arbor layer was 3.5736 t/(hm²·a), which accounted for 84.01%. __________ Translated from Scientia Silvae Sinicae, 2008, 44(3): 34–39 [译自: 林业科学]     

黄土丘陵区小流域林业土地生产潜力研究

黄土丘陵区小流域林业土地生产潜力研究＊王冬梅孙保平刘敬军关键词黄土丘陵区小流域土地生产潜力气候生产潜力现实生产潜力土地是由土壤、气候、地貌、岩石、植被和水文等因素组成的自然历史综合体,是一切生产和一切生物生存的源泉。长期以来,黄土高原由于人口数量的迅...     

Effects of canopy interception on energy conversion processes in a Chinese fir plantation ecosystem

The functions of canopy interception on energy conversion processes in a Chinese fir plantation ecosystem were studied with the aid of long-term observation data in Huitong. The results showed that the absorbed, penetrated and reflected amounts of solar radiation were, respectively, 2.5543 × 10⁹ J/(m²·year) (absorption rate of 0.827), 2.5306 × 10⁸ J/(m²·year) (penetration rate of 0.082), and 2.7432 × 10⁸ J/(m²·year) (reflection rate of 0.091) by the canopy. The conversion of net solar radiation to latent heat in the process of evaporation from canopy interception amounted to 6.3695 × 10⁸ J/(m²·year) (accounting for 22.9% of total ecosystem net radiation and 30.4% of ecosystem evaporation), which was an important part of the budget of the energy system. Canopy interception consumed kinetic energy of raindrops in overcoming resistance of branches and leaves, which collected raindrops, followed with the conversion of potential energy in raindrops to kinetic energy with falling raindrops. In general, the diameter of raindrops from the canopy is larger than that of the raindrops above the canopy as a result of the collection effort by the canopy. The kinetic energy of raindrops from the canopy, therefore, was higher than that of raindrops in the atmosphere. The drop-size distribution from the canopy was affected by the structure of the canopy layer rather than the amount of precipitation and precipitation intensity. The canopy had no important nor efficient effects on decreasing the kinetic energy of raindrops in our case study with a first branch height of 7 m and precipitation amounts over 3 mm. However, the canopy would play a key role in decreasing kinetic energy of raindrops in two cases, that of a small amount of precipitation and one of heavy precipitation intensity, in which the canopy could intercept the largest amount of precipitation in the former condition and the canopy could scatter bigger raindrops to smaller raindrops with striking leaves in the case of heavy precipitation. __________ Translated from Scientia Silvae Sinicae, 2007, 43(2): 15–20 [译自: 林业科学]     

湖南第2代杉木幼林的水文学过程及养分动态研究

采用小集水区技术和定位研究方法 ,根据连续 3a观测所取得的数据 ,对湖南会同第 2代杉木幼林的水量平衡和养分元素的地球化学循环进行了研究。结果表明 :该森林生态系统年降雨输入为 1170 6mm ,其中 3 5 3mm以树干茎流形式进入林地 ,占降雨量的 0 3% ,林内穿透水为 10 17 3mm ,占 86 9% ,另外林冠年截留量为 149 77mm ,占年降雨量的 12 8%。以径流形式流出该系统的水量为 42 8 0 5mm ,占年降雨量的 36 5 7% ,其中地表径流和地下径流分别占总径流的 4 31%和 95 6 9%。系统另一输出形式蒸散量为 86 2 6 4mm ,为年降雨量的 6 2 2 %。在该森林生态系统中 ,由降雨输入的N、P、K、Ca、Mg等元素的总量为 5 3 173kg·hm- 2 ·a- 1 ,径流输出量为 42 5 6 3kg·hm- 2 ·a- 1 ,净积累量为 10 6 10kg·hm- 2 ·a- 1 。与稳定态的第 1代杉木林相比 ,第 2代杉木幼林的林冠截留量成倍减少 ,地表径流、地下径流量和径流总量都高于第 1代杉木林 ,其涵养水源的能力相对较弱 ,抵抗外界干扰的能力比稳定态的第 1代杉木林差。从生物循环来看 ,第 2代杉木幼林的养分存留量大 ,表明第 2代杉木幼林将从土壤中吸收的养分大量地保存在林木中 ,造成土壤中养分的逐渐减少 ,维持持久的林地生产力应引起重视。第 2代杉木幼林     

Root biomass and productivity in dominant plantation populations in the mountainous area in western Sichuan

This study investigated root biomass and productivity in dominant populations in western Sichuan, China. A total of 4 plots (Picea balfouriana plantation for 22 age in Maerkang, 9 trees, mean DBH of population for 10.4 cm and height for 10.5 m; Larix maxteriana plantation for 22 age in Wolong, 9 trees, mean DBH of population for 17.0 cm and height for 13.8 m; Abies fabri plantation for 35 age in Ebian, 18 trees, mean DBH of population for 14.1 cm and height for 11.9 m; Larix kaempferi plantation for 23 age in Miyaluo, 8 trees, mean DBH of population for 17.4 cm and height for 14.5 m; a 20 m×25 m plot located on each of the 4 types in western Sichuan, China) were randomly selected and excavated to a depth of 60 cm for each of the 4 plantation types. To estimate the root biomass of an individual tree using D ² H, an exponential model was selected with the highest coefficient ranging from 0.94 to 0.99. The total root biomass per hm² varied among plantation population types following the order: L. kaempferi (37.832 t/hm²) > A. fabri (24.907 t/hm²) > L. maxteriana (18.320 t/hm²) > P. balfouriana (15.982 t/hm²). The biomass fractions of a given root size class compared to the total root biomass differed among plantation population types. For all 4 studied plantation types, the majority of the roots were distributed in the top 40 cm of soil, e.g., 97.88% for P. balfouriana population, 96.78% for L. maxteriana, 95.65% for A. fabri, and 99.72 for L. kaempferi population. The root biomass fractions distributed in the top 20 cm of soil were 77.13% for P. balfouriana, 77.13% for L. maxteriana, 65.02% for A. fabri and 80.66% for L. kaempferi, respectively. The root allocation in the 0–20, 20–40, and 40–60 cm soil layers gave ratios of 34:12:1 for P. balfouriana, 24:6:1 for L. maxteriana, 15:7:1 for A. fabri, and 64:4:1 for L. kaempferi populations. The root biomass density of dominant plantation population was 10.782 t/(hm²·m) for P. balfouriana, 8.230 t/hm²·m) for L. maxteriana, 24.546 t/(hm²·m) for A. fabri, and 13.211 t/(hm²·m) for L. kaempferi population, respectively. The root biomass productivity was found to be 0.57 t/(hm²·year) for P. balfouriana, 0.83 t/(hm²·year) for L. maxteriana, 0.71 t/(hm²·year) for A. fabri and 1.64 t/(hm²·year) for L. kaempferi population, respectively. __________ Translated from Acta Ecologica Sinica, 2006, 26(2): 542–551 [译自: 生态学报, 2006, 26(2): 542–551]