Ecological environment analysis of Abies holophylla plantations under different cutting systems

TheAblesholOPhyllsplantationswerefosterednotonlyforhigheconomicprofit,butalsoforthegoodofasoundecologicalenvironment.So,theenvironmentassessmentwasstressedduringafforestationandmanagementtobuilttheorybaseforecologicalengineering.SoilerosionrateThreetypesofstands,Japanesexylosmaforest,standsofselectivecut-ting,andstandsofclearCutting,wereinvestigated.Gradient,soilthickness,vegetationandsoilerosionweresurveyed(T8ble1).OnestandOftypeillwithgradientof45"andvegetationcoverageof10%hasthehighests…     

Tree productivity and water potential productivity in returning farmland to forest project in Datong County,Qinghai Province

From 2002 to 2003, based on the investigation of sample plots and stem analysis of remained plantation communities in the areas of returning farmland to forest in the 1980s in Datong County, Qinghai Province, this paper studies tree productivity and moisture potential productivity of six types of plantations on the land of returning farmland to forest, such as green poplar (Populus cathayana Rehd.) and shrub mixed forest, Asia white birch (Betula platyphylla) and China spruce (Picea asperata) mixed forest, Dahurian larch (Larix gmelinii) pure forest, China spruce pure forest and Asia white birch pure forest and so on. The results show that: in sub-humid region of Loess Plateau, 3 000 trees per hm² is a proper standard of planting density. Under current condition, the productivity index of green poplar and shrub mixed forest, Asia white birch pure forest, China spruce pure forest, and Asia white birch and China spruce mixed forest with the density of 2 100–3 333 trees per hm² can serve as potential productivity standard of actual biomass of arbor established forest. In sub-humid area, Thornthwaite Model is adopted to estimate plant climate potential productivity, which is about 8 462 kg•hm^–2•a^–1. The actual potential water productive efficiency of Purplecone spruce (Picea purpurea) and Asia white birch pure established forest are 17.22 and 22.14 kg•mm^–1•hm^–2•a^–1 respectively, and that of green poplar and shrub mixed established forest, and Asia white birch and China spruce mixed established forest are 21.14 and 19.09 kg•mm^–1•hm^–2•a^–1 respectively. The potential productivity of green poplar and shrub mixed forest, Asia white birch and China spruce mixed forest, China spruce pure forest and Asia white birch pure forest which have grown into forest with the density of 3 000 trees per hm² have attained or been close to that of local climax community, which is local maximum tree productivity at present. These types of forestation models are the developing direction of the returning farmland to forest project.     

桂西北秃杉人工林土壤肥力变化的研究

采用时空互换法,于广西南丹县山口林场选取不同林龄(9、14、20 a)的秃杉人工林作为研究对象,对其土壤物理性质、化学性质和生物化学性质(土壤酶活性)进行研究。结果表明:不同林分年龄土壤性质存在一定的差异,8、14、20 a秃杉人工林表层土壤(0 20 cm)土壤密度分别为0.978、0.914、0.890 g·cm^-3,总孔隙度分别为63.10%、65.53 %、66.40%,土壤最大持水量分别为64.55%、71.70%、74.58%。随着林龄的增长,土壤各化学和生物化学指标的变化不尽相同,但林分年龄到20年生时,多数土壤养分和酶活性指标都有所升高,土壤肥力状况得到提高。     

孟加拉吉大港地区丘陵森林有机物积累

在孟加拉吉大港丘陵地区,调查了热带季风气候条件下的3种人工林(7年生大叶相思(Acacia auriculiformis)林、15年生大叶相思林和18年生混交林)和1种天然林的森林凋落物及其对土壤性质的作用.结果表明,总的有机质积累随人工林树龄增加而增加,但是年积累量随之降低.在同一植被类型内,不同坡位新鲜或部分分解的凋落物有机质累计量变化较大,坡底部有机质积累量最高,沿着山坡向上逐渐减少.在15年生大叶相思人工林内,土壤整合有机物积累量变化趋势与新鲜或部分分解有机质积累量变化趋势相反.在7年生和15年生的大叶相思林以及18年龄的阔叶混交人工林内,新鲜、部分分解和完全分解(含土壤整合有机质)有机质总生产速率分别是2554.31、705.79和1028.01kg.ha-1·a-1,新鲜凋落物有机质在3种林分中的生产速率分别是38.23,19.40和30.48 kg·ha-1·a-1.3种人工林和自然林内,平均新鲜凋落物的有机质积累占有机质产出总量的32.45%,部分分解凋落物占13.50%,而全分解整合土壤有机质占54.56%.森林土壤酸度随凋落物分解阶段的深入而增加.     

杉木纯林、混交林土壤微生物特性和土壤养分的比较研究

本文于2005年5月份,在中国科学院会同森林生态实验站选择了一块15年生的杉木纯林和两块15年生杉阔混交林作为研究对象,调查了林地土壤有机碳、全氮、全磷、硝态氮、有效磷和土壤微生物碳、氮、磷、基础呼吸以及呼吸熵,比较了纯林和混交林土壤微生物特性和土壤养分.结果表明,杉阔混交林的土壤有机碳、全氮、全磷硝态氮和有效磷含量高于杉木纯林;在混交林中,土壤微生物学特性得到改善.在0(10 cm和10(20 cm两层土壤中,杉阔混交林土壤微生物氮含量分别比杉木纯林高69%和61%.在0(10 cm土层,杉阔混交林土壤微生物碳、磷和基础呼吸分别比杉木纯林高11%、14%和4%;在10(20 cm土层,分别高6%、3%和3%.但是,杉阔混交林土壤微生物碳:氮比和呼吸熵较杉木纯林低34%和4%.另外,土壤微生物与土壤养分的相关性高于土壤呼吸、微生物碳:氮比和呼吸熵与土壤养分的相关性.由此可知,在针叶纯林中引入阔叶树后,土壤肥力得以改善,并有利于退化森林土壤的恢复.     

德国中部Soiling云杉-山毛榉混交林冠层组成对土壤CO2排放的影响

It was hypothesized that soil respiration can be affected by canopy composition. Hence, admixture of trees as a common forest management practice may cause significant change in the carbon cycling. This study was conducted in a mixed spruce-beech stand at Solling forest in central Germany to investigate the effect of canopy composition on soil respiration. The canopy cover was classified in four major canopy classes (pure beech, pure spruce, mixed and gap), and the area under each canopy class was identified as a sub-plot. Soil respiration in each sub-plot (n=4) was measured monthly from Jun 2005 to July 2006. Results show significant difference in annual soil respiration between the beech (359 g·m⁻²·a⁻¹ C) and gap (211 g·m⁻²·a⁻¹ C) sub-plots. The estimation of the total below-ground carbon allocation (TBCA) based on a model given by Raich and Nadelhoffer revealed considerably higher root CO₂ production in the beech sub-plot (231 g·m⁻²·a⁻¹ C) compare to the gap sub-plot (51 g·m⁻²·a⁻¹ C). The contribution of the root respiration to the total soil respiration was higher in the soil under the beech canopy (59%) compared with the soil in the gap (29%). The findings suggested that the condition under the beech canopy may cause more desirable micro-site for autotrophic respiration and consequently higher CO₂ release into the atmosphere.     

孟加拉哈提亚地区海岸造林对土壤性质的影响

在孟加拉诺阿卡利地区及相临裸地,对海岸植被(12年和17年生无瓣海桑Sonneratia apetala)进行探索性研究,以便了解海岸造林对土壤特性的影响.在三种不同地带(内陆、中部、海边),在12年生和17年生无瓣海桑林下,土壤深度分别为0-10,10-30和30-40cm,土壤湿度、土壤粒度、有机质、C含量、总N、pH、有效P、K、Na、Ca和Mg含量明显高(p≤0.05,p≤0.01,p≤0.001)于其相临裸地的数据,土壤含盐量明显(p≤0.01)低于其相临裸地的数据.在内陆CharAlim植被,土壤表面的土壤湿度,土壤粒度,有机质,C含量、总N、pH、土壤含盐量、有效P、K、Na、Ca和Mg含量分别为:31.09%、2.24 g·cm-3、2.41%、4.14%、0.58%、7.07、O.09 dS·cm-1、28.06 mg·L-1、O.50 mg·L-1、11.5 mg·L-1、3.30 mg·L-1和2.7 mmol·kg-1;而在相邻的Char Rehania贫瘠地区的相同土壤深度,其相关值分别为:16.69%、1.25g·cm-3、O.43%、0.74%、O.25%、6.57、0.13 dS·cm-1、13.07mg·L-1、O.30mg·L-1、1.4 mg·L-1、O.30 mmol·kG-1和0.50 nag·L-1.然而,在小内陆到海边的植被中,土壤湿度、土壤密度、有机质、C含量、总N、pH、有效P、K、Na和Ca含量逐渐降低,而土壤含盐量、Na和Mg含量却逐渐增加.虽然,在植被与相临裸地的不同土壤深度中土壤质地不同,植被地中砂土份额明显(p≤0.01)低于相临裸地,而粉砂土份额则明显(p≤0.001)高于裸地.在本研究中,所有参数的评价也在为其他地区相关研究得到应用.     

The runoff characteristics and harmonic analysis of the soil moisture dynamics in<Emphasis Type="Italic">Robinia pseudoacacia</Emphasis> stand

Robinia pseudoacacia stands act as a typical ecological protection forest in hilly semi-arid area of China. Two fields of surface runoff were separately set up inR. pseudoacacia stand and its clearcut area in the western Liaoning Province (18°50’–122°25’ E, 40°24’–42°34’ N) for measuring the characteristics of runoff and sediment as well as soil moisture dynamics. Contractive analysis of the two land types showed that there existed a significant difference in volumes of runoff and sediment between the sites ofR. pseudoacacia stand and its clearcut area. The runoff volume and sediment volume in clearcut are were much bigger than those inR. pseudoacacia stand, with an increase amount of 40%–177% for runoff and 180%–400% for sediment. Hydrograph of surface runoff of typical rainfall showed that the peak value of runoff inR. pseudoacacia stand was decreased by 1.0–2.5×10⁻³m³·s⁻¹ compared with that in its clearcut area, and the occurring time of peak value of runoff inR. pseudoacacia stand was 10–20 min later than that in its clearcut area. Harmonic analysis of soil moisture dynamics indicated that the soil moisture inR. pseudoacacia stand was 2.3% higher than that in clearcut area, and the soil moisture both inR. pseudoacia stand and its clearcut area could be divided into dry season and humid season and varied periodically with annual raifall precipitation. It was concluded thatR. pseudoacacia stand plays a very important role in storing water, increasing soil moisture, and reducing surface runoff and soil erosion. Foundation item: This paper was supported by Chinese “863” Plan Water-Saving Agriculture (2002AA2Z4321), the Key Knowledge Innovation Project (SCXZY0103), and The “Tenth-five” Plan of Liaoning Province (2001212001). Biography: GAO Peng (1967-), male, Dr. candidate, associate professor of Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China. Responsible editor: Song Funan     

Soil animals and nitrogen mineralization under sand-fixation plantations in Zhanggutai region,China

The effects of soil animals on soil nitrogen （N） mineralization and its availability were studied by investigating soil animal groups and their amounts of macro-faunas sorted by hand, and middle and microfaunas distinguished with Tullgren and Baermann methods under three Pinus sylvestris var. mongolica Litv. plantations in Zhanggutai sandy land, China. In addition, soil N mineralization rate was also measured with PVC closed-top tube in situ incubation method. The soil animals collected during growing season belonged to 13 orders, 5 groups, 4 phyla, whose average density was 86 249.17 individuals-m^-2. There were significant differences in soil animal species, densities, diversities and evenness among three plantations. Permanent grazing resulted in decrease of soil animal species and diversity. The average ammonification, nitrification and mineralization rates were 0.48 g：m^-2·a^-1, 3.68 g·m^-2·a^-1 and 4.16 g·m^-2·a^-1, respectively. The ammonification rate in near-mature forest was higher than that in middle-age forests, while the order of nitrification and net mineralization rates was： middle-age forest without grazing 〈 middle-age forest with grazing 〈 near-mature forest with grazing （P〈0.05）. Soil N mineralization rate increased with soil animal amounts, but no significant relationship with diversity. The contribution of soil animals to N mineralization was different for different ecosystems due to influences of complex factors including grazing, soil characteristics, the quality and amount of litter on N mineralization.     

Function and value of water conservation in different age classes of Acacia mangium plantations

For this paper, we studied the water-holding capacity of canopy, vegetation layer under canopy and litter layer, the water-holding capacity and permeability of soil as well as their changes with growth of stands in Acacia mangium plantations of three different age classes (four-, seven-and 11-year-old). Results show that total water-holding above ground in the order of 11-year stand age (52.86 t/hm²)>seven-year stand age (41.90 t/hm²)>seven-year stand age (25.78 t/hm²), the increment tendency increased with stand age. Similar sequence also obtained on the water-holding capacity and permeation capacity of soil (0–40 cm). The total water-storage capacity both above ground and soil in four-year-old, seven-year-old and 11-year-old of A. mangium plantations were 2,023.0, 2,158.4 and 2,260.4 t/hm², respectively, and the all value of water conservation were 1,372.70, 1,474.42 and 1,549.91 yuan (RMB)/hm², respectively. Therefore, A. mangium plantation had a good ability to modify soil structure and good water conservation function. __________ Translated from Journal of Soil and Water Conservation, 2006, 20(5): 5–8, 27 [译自: 水土保持学报]     

Interspecific competition impacts on the morphology and distribution of fine roots in European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.)

Morphology and vertical distribution patterns of spruce and beech live fine roots (diameter ≤2 mm) were studied using a soil core method in three comparable mature stands in the Solling: (1) pure beech, (2) pure spruce and (3) mixed spruce–beech. This study was aimed at determining the effects of interspecific competition on fine root structure and spatial fine root distribution of both species. A vertical stratification of beech and spruce fine root systems was found in the mixed stand due to a shift in beech fine roots from upper to lower soil layers. Moreover, compared to pure beech, a significantly higher specific root length (SRL, P<0.05) and specific surface area (SSA, P<0.05) were found for beech admixed with spruce (pure beech/mixed beech SRL 16.1–23.4 m g⁻¹, SSA 286–367 cm² g⁻¹). Both indicate a flexible ‘foraging’ strategy of beech tending to increase soil exploitation and space sequestration efficiency in soil layers less occupied by competitors. Spruce, in contrast, followed a more conservative strategy keeping the shallow vertical rooting and the root morphology quite constant in both pure and mixed stands (pure spruce/mixed spruce SRL 9.6/7.7 m g⁻¹, P>0.10; SSA 225/212 cm² g⁻¹, P>0.10). Symmetric competition belowground between mixed beech and spruce was observed since live fine roots of both species were under-represented compared to pure stand. However, the higher space sequestration efficiency suggests a higher competitive ability of beech belowground.     

Effects of intercropping systems of trees with soybean on soil physicochemical properties in juvenile plantations

The intercropping system of tree with soybean in juvenile plantations, as a short-term practice, was applied at Lao Shan Experimental Station in Mao’er Shan Forest of Northeast Forestry University, Harbin, China. The larch (Larix gmelinii)/soybean (Glycine max.) and ash (Fraxinus mandshurica) intercropping systems were studied in the field to assess the effects of the intercropping on soil physicochemical properties. The results showed that soil physical properties were improved after soybean intercropping with larch and ash in one growing season. The soil bulk density in larch/soybean and ash/soybean systems was 1.112 g·cm⁻³ and 1.058 g·cm⁻³, respectively, which was lower than that in the pure larch or ash plantation without intercropping. The total soil porosity also increased after intercropping. The organic matter amount in larch/soybean system was 1.77 times higher than that in the pure larch plantation, and it was 1.09 times higher in ash/soybean system than that in the pure ash plantation. Contents of total nitrogen and hydrolyzable nitrogen in larch/soybean system were 4.2% and 53.0% higher than those in the pure larch stand. Total nitrogen and hydrolyzable nitrogen contents in ash/soybean system were 75.5% and 3.3% higher than those in the pure ash plantation. Total phosphorus content decreased after intercropping, while change of available phosphorus showed an increasing trend. Total potassium and available potassium contents in the larch/soybean system were 0.6% and 17.5% higher than those in the pure larch stand. Total potassium and available potassium contents in the ash/soybean system were 56.4% and 21.8% higher than those in the pure ash plantation. Biography: FAN A-nan (1972–), female, Ph. Doctor in Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China.     

毛竹扩张对常绿阔叶林土壤性质的影响及相关分析

[目的]为探讨毛竹向邻近常绿阔叶林扩张对土壤性质的影响。[方法]本研究选取江西大岗山森林生态定位站常绿阔叶林、2∶8竹阔混交林、8∶2竹阔混交林和毛竹纯林为研究对象,对土壤有机碳、密度、孔隙度、持水量和贮水量等土壤性质和水分特征进行研究。[结果]常绿阔叶林在毛竹扩张过程中,土壤碳元素含量呈先增后降的趋势。相关分析表明:土壤有机碳与非毛管持水量和现有贮水量呈极显著相关,与土壤密度和总孔隙度呈显著相关,各指标相互作用共同影响了土壤有机碳含量在扩张过程中的变化特征。[结论]常绿阔叶林表层土壤密度、孔隙度和持水量等特征综合优于混交林和毛竹纯林,这为竹鞭扩张后竹笋萌发创造了条件;当常绿阔叶林演替到毛竹纯林时,10 60 cm土壤物理性质和持水能力都有所改善,但有机碳含量降为4个林分最低值,大量竹鞭虽然优化了土壤物理性质,但无性繁殖导致土壤碳元素大量消耗,加之择伐和挖笋等人工干扰,毛竹纯林土壤有机碳含量较低。调节土壤碳含量以及土壤结构和水分特征可能是今后控制毛竹林扩张,维持群落生态系统稳定性的重要生态策略。     

Soil nitrogen transformations varied with plant community under Nanchang urban forests in mid-subtropical zone of China

Soil N transformations using the polyvinyl chloride (PVC) closed-top tube in situ incubation method were studied in Nanchang urban forests of the mid-subtropical region of China in different months of 2007. Four plots of 20 m × 20 m were established in four different plant communities that represented typical successional stages of forest development including shrubs, coniferous forest, mixed forest and broad- leaved forest. Average concentrations of soil NH 4 + -N from January to December were not different among the four plant communities. The concentrations of soil NO 3 - -N and mineral N, and the annual rates of ammonification, nitrification and net N-mineralization under the early successional shrub community and coniferous forest were generally lower than that of the late successional mixed and broad-leaved forests (p<0.05). Similar differences among the plant communities were also shown in the relative nitrification index (NH 4 + -N/NO 3 - -N) and relative nitrification intensity (nitrification rate/net N-mineralization rate). The annual net N-mineralization rate was increased from younger to older plant communities, from 15.1 and 41.4 kg·ha -1 ·a -1 under the shrubs and coniferous forest communities to 98.0 and 112.9 kg·ha -1 ·a -1 under the mixed and broad-leaved forests, respectively. Moreover, the high annual nitrification rates (50-70 kg·ha -1 ·a -1 ) and its end product, NO 3 - -N (2.4-3.8 mg·kg -1 ), under older plant communities could increase the potential risk of N loss. Additionally, the temporal patterns of the different soil N variables mentioned above varied with different plant community due to the combined affects of natural biological processes associated withforest maturation and urbanization. Our results indicated that urban for- ests are moving towards a state of "N saturation" (extremely nitrification rate and NO 3 - -N content) as they mature.     

不同林龄马尾松人工林土壤碳氮磷生态化学计量特征

[目的]研究了马尾松从幼龄林至成熟林生长序列中的土壤有机C、全N、全P含量及其生态化学计量特征,以丰富该区域马尾松生态系统生态化学计量学领域的基础研究。[方法]以广西凭祥4个林龄(6、16、23、35 a)马尾松人工林为研究对象,每个林龄选取3块林分,每个林分内设置一个400 m2的调查样地,按照0 20、20 40、4060 cm三层土层取样,采用不同林分土壤化学计量的对比实验测定土壤CNP,采用单因素方差分析的LSD法进行显著性检验。[结果]表明:4个林龄马尾松人工林0 20 cm土壤有机C、全N、全P含量分别为5.73 15.56、0.691.23、0.17 0.23 g·kg-1,是20 40 cm土层的1.51、1.31、1.06倍,40 60 cm土层的1.97、1.58、1.06倍。土壤有机C含量、全N含量均随林龄的递增先降低后增加,随土层加深持续降低;土壤全P含量在林龄和土层间均无显著性变化;林龄对土壤C∶N、N∶P有极显著的影响(P=0.001,P=0.000),土层对土壤C∶P、N∶P有显著性影响(P=0.000,P=0.014)。[结论]土壤有机C、全N含量从成熟林阶段开始回升;N在不同林龄间和不同土层间的变化是土壤N∶P变化的主要原因;土壤C∶N、C∶P主要受有机C的影响。     

日本北海道北部寒温带森林流域林冠层凋落物及其养分归还量的景观格局(英文)

Within a forested watershed at the Uryu Experimental Forest of Hokkaido University in northern Hokkaido, overstory litterfall and related nutrient fluxes were measured at different landscape zones over two years. The wetland zone covered with Picea glehnii pure stand. The riparian zone was deciduous broad-leaved stand dominated by Alnus hirsuta and Salix spp., while the mixture of deciduous broadleaf and evergreen conifer dominated by Betula platyphylla, Quercus crispula and Abies sachalinensis distributed on the upland zone. Annual litterfall averaged 1444, 5122, and 4123 kg.hm^-2·a^-1 in the wetland, riparian and upland zones, respectively. Litterfall production peaked in September-October, and foliage litter contributed the greatest amount （73.4%-87.6 %） of the annual total litterfall. Concentrations of nutrients analyzed in foliage litter of the dominant species showed a similar seasonal variation over the year except for N in P glehnii and A. hirsuta. The nutrient fluxes for all elements analyzed were greatest on riparian zone and lowest in wetland zone. Nutrient fluxes via litterfall followed the decreasing sequence： N （11-129 kg.hm-2.aq） 〉 Ca （9-69） 〉 K （5-20） 〉 Mg （3-15） 〉 P （0.4-4.7） for all stands. Significant differences were found in litterfall production and nutrient fluxes among the different landscape components. There existed significant differences in soil chemistry between the different landscape zones. The consistently low soil C：N ratios at the riparian zone might be due to the higher-quality litter inputs （largely N-fixing alder）.     

北京九龙山不同林分枯落物及土壤水文效应

对北京九龙山油松、侧柏、黄栌3种纯林的枯落物层水文效应和土壤水分效应进行研究,结果表明:黄栌林分的枯落物总蓄积量最大,为13.15 t·hm-2,其次为油松和侧柏,分别为12.50、9.53 t·hm-2;黄栌的最大持水量和有效拦蓄量最大,分别为28.73、23.17 t·hm-2;侧柏的最小,分别为12.67、10.17 t·hm-2。未分解层和半分解层枯落物持水量分别在浸泡10 h后和8 h后达到饱和,二者的吸水速率均在浸泡2 h内最大,4 h后趋于平稳。不同层次枯落物持水量、吸水速率与浸泡时间均存在较好的函数关系;3个林地的土壤密度均值最大的为侧柏(1.30 g·cm-3),其次为油松和黄栌,分别为1.23、1.08 g·cm-3;黄栌的总孔隙度最大,为49.63%,其次为油松和侧柏,分别为49.49%、47.44%;侧柏林地的土壤有效持水量最大,为96.53 t·hm-2,其次为黄栌和油松,分别为88.23、69.00 t·hm-2。对入渗速率与入渗时间进行拟合分析,二者呈幂函数关系,其相关系数R2值均在0.90以上。     

A new methodology for estimating forest NPP based on forest inventory data—A case study of Chinese pine forest

Accurately estimating forest net primary productivity (NPP) plays an important role in study of global carbon budget. A NPP model reflecting the synthetic effects of both biotic (forest stand age, A and stem volume, V) and climatic factors (mean annual actual evapotranspiration, E) was developed for Chinese pine (Pinus tabulaeformis) forest by making full use of Forest Inventory Data (FID) and dynamically assessing forest productivity. The NPP of Chinese pine forest was estimated by using this model and the fourth FID (1989–1993), and the spatial pattern of NPP of Chinese pine forest was given by Geography Information System (GIS) software. The results indicated that mean NPP value, of Chinese pine forest was 7.82 t m⁻²·a⁻¹ and varied at the range of 3.32–11.87 t hm⁻²·a⁻¹. NPP distribution of Chinese pine forests was significantly different in different regions, higher in the south and lower in the north of China. In terms of the main distribution regions of Chinese pine, the NPPs of Chinese pine forest in Shanxi and Shaanxi provinces were in middle level, with an average NPP of 7.4 t hm⁻²·a⁻¹, that in the southern and the eastern parts (e.g. Shichuang Hunan, Henan, and Liaoning provinces) was higher (over 7.7 t hm⁻²·a⁻¹), and that in the northern part and western part (e.g. Neimenggu and Ningxia provinces) was lower (below 5 t hm⁻²·a⁻¹). This study provides an efficient way for using FID to understand the dynamics of foest NPP and evaluate its effects on global climate change. Foundation item: This study was supported by the National Natural Science Foundation of China (Nos. 30028001, 49905005), National Key Basic Research Specific Foundation (G1999043407); the Chinese Academy of Sciences (KSC2-1-07). Biography: ZHAO Min (1973-), female, Ph. D. in Laboratory of Quantitative Vegetation Ecology, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, P. R. China. Responsible editor: Zhu Hong     

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]     

Carbon return and dynamics of litterfall in natural forest and monoculture plantation of Castanopsis kawakamii in subtropical China

The amount of carbon returned through litterfall and its seasonal pattern were studied in a natural forest of Castanopsis kawakamii (NF) and adjacent monoculture plantations of C. kawakamii (CK) and Chinese fir (Cunninghamia lanceolata) (CF) in Sanming, Fujian Province, China. Mean annual carbon return through total litterfall over 3 years (from 1999 to 2001) was 5.097 t·hm⁻² in the NF, 4.337 t·hm⁻² in the CK and 2.502 t·hm⁻² in the CF respectively. Of the total carbon return in the three forests, leaf contribution accounted for 58.96%, 68.53% and 56.12% and twig 24.41%, 22.34% and 26.18%, respectively. The seasonal patterns of carbon return from total litterfall and leaf-litter were quite similar among the three forests. A peak of carbon input from litterfall in the NF and the CK occurred in spring except for the highest annual C return through branch litter of the NF in summer, while the CF showed the maximum C return in summer. The results of this study demonstrate that the natural forest has a greater C return through litterfall than monoculture plantations, which is beneficial to the increase of soil organic matter storage and the maintenance of soil fertility. [Supported by the Teaching and Research Award Program of MOE P.R.C. (TRAPOYT) and the Key Basic Research Project of Fujian Province (2000F004)]