Runoff and sediment concentration of different parts of a road in Hyrcanian forests

Road prisms, such as cutslopes, fillslopes and road surfaces, can be important contributors of sediment to streams in forested watersheds. In this study rainfall simulations were carried out on cutslopes, fillslopes, road surfaces and forest grounds in hardwood forests of Lolet and Lat Talar, Iran. Water at intensity of 32.4 mm·h 1 was sprayed from a nozzle onto a square area of 0.48 m 2 . Runoff was collected by water gauge every 4 min and then runoff and sediment parameters were measured in each plot. Results indicated that on road surfaces, the runoff coefficient was 63.28%. On the cutslopes and fillslopes, the runoff coefficients were 35.14% and 10.23%, respectively. On the forest ground as a control, the runoff coefficient was 5.90%. Runoff volume was 2.73 mL·s-1 on the road surfaces and 1.52 mL·s-1 on cutslopes. On fillslopes the runoff volume was 0.44 mL·s-1 and on the forest ground 0.25 mL·s-1 . The greatest rate of soil loss was found on the cutslope (280.79 g·m-2·h-1). The total soil loss from the cutslopes was two times higher than that from the road surfaces and six times higher than that from the fillslopes. We conclude that cutslopes can be considered the main source of sediments in our study sites, but the function of road surface as a source of runoff generation is more important.     

Effect of alley cropping on soil aggregate stability of a tropical Alfisol

The beneficial effect of organic matter on soil aggregate stability is well documented. Alley cropping has been suggested as a possible alternative to maintain soil organic matter content in cropping systems without fallowing the land. The objective of this study was to asses the effect of alley cropping on dry and wet soil aggregate stability on land degraded by shifting cultivation. The aggregate size distribution by dry sieving, aggregate stability by wet sieving, soil organic Carbon content and soil bulk density were measured following two and three years of alley cropping with Gliricedia (Gliricidia sepium) and Pigeon pea (Cajanas cajan) in a tropical Rhodustalf. Alley cropping increased the mean aggregate diameter and water stability of soil aggregates. The mean aggregate diameter obtained from dry sieving increased from 1.3 mm of the control to 2.68 and 3.11 mm after three years in Pigeon pea and Gliricidia alley cropped plots, respectively. This is an indication of resistance to wind erosion in alley cropped plots. The wet aggregate stability which shows the resistance to erosion by water also increased in alley cropped plots. These increases were significant after three years of hedge row establishment. The increase in soil organic C in alley cropped plots contributed to the higher dry and wet aggregate stability, and decreased soil bulk density. The improvement was higher in plots alley cropped with Gliricidia than Pigeon pea. This study shows the importance of ally cropping in increasing aggregate stability of degraded sandy soils which in return reduce erosion by wind and water.     

不同海拔毛竹土壤酶活性与土壤理化性质关系的研究

以江西省大岗山地区的毛竹林为研究对象,利用相关分析和主成分分析对不同海拔(300、400、500、600、700m)土壤纤维素酶、蔗糖酶、淀粉酶、β-葡糖苷酶和多酚氧化酶活性的变化特征进行了分析,探讨了其与土壤理化性质的关系。结果表明:土壤化学指标表现出随海拔的升高而增加的变化特征,除碱解氮外,其他各指标均处于较低水平,但物理指标的变化各不相同;随海拔升高,β-葡糖苷酶与多酚氧化酶活性呈现出增加的趋势,而纤维素酶、蔗糖酶和淀粉酶活性无明显变化规律;几种土壤酶对土壤肥力的指示效果不同,β-葡糖苷酶在评价毛竹林土壤肥力上具有重要指示效果,其后依次为蔗糖酶和多酚氧化酶、纤维素酶,但淀粉酶不适宜用来评价土壤肥力状况;通过主成分分析计算综合得分,不同海拔毛竹土壤肥力随海拔的升高而增加。     

不同采伐强度对闽西常绿阔叶林林分结构稳定性的影响

应用多样性分析方法和改进后的 M.Godron 稳定性测定方法研究常绿阔叶林5种不同强度采伐(弱度9.8%、中度24.5%,强度46.8%和极强度72.3%和皆伐)作业10 a后林分结构稳定性.结果表明,择伐林地林分处于稳定状态,随着择伐强度的增强,林分的稳定性开始逐渐降低.皆伐林地林分处于不稳定状态.对于常绿阔叶林的科学经营,从稳定性出发,应尽量采取择伐方式,尤其是中低强度的择伐方式.     

利用重要值评价森林生态系统稳定性

本文利用重要值评价森林生态系统稳定性,得出在红松纯林和云冷杉纯林中,红松和冷杉的重要值都是最大,其它树种的重要值都比较小;在红松混交林和云冷杉混交林中,红松和云杉的重要值均有明显下降,阔叶树的重要值均有明显上升,从而进一步说明混交林自我更新、自我维持、自我调节的能力强,是相对稳定的合理结构。     

加强塞罕坝林区路网建设的必要性及策略探究

介绍了当前塞罕坝机械林场林区路网建设的概况,指出当前塞罕坝林区路网建设存在的主要问题及其滞后原因,并阐述了加强林区道路建设的必要性,在此基础上提出塞罕坝林区路网建设的对策与建议,旨在提高林区人们对林区路网建设重要性的认识,为实现林业现代化,林业经营集约化,森林资源可持续发展提供相关的理论支持。     

林区路网规划设计与路网技术标准的确定方法

本文介绍了林区路网规划设计的优化方法和路网技术标准的确定。     

森林采伐更新作业与林地生产力的维护

根据森林资源可持续发展的要求,分析了采运作业可能引起林地生产力下降的因素,并提出了减缓措施。     

退耕还林不同人工林类型对土壤养分的影响

对内蒙古敖汉旗2006年退耕还林的樟子松纯林、山杏纯林、山杏沙棘混交林和荒草地（对照）不同深度的土壤养分状况进行研究,结果表明：3种人工林的土壤有机质和碱解氮含量明显增加,山杏沙棘混交林中沙棘林带表层的速效磷含量明显增加,山杏纯林浅层的速效钾含量明显增加;3种人工林和荒草地的土壤养分随着土壤深度的增加而降低,表层土壤养分条件较好,说明土壤养分具有很强的表聚性;3种人工林与荒草地相比都不同程度地提高了土壤养分水平,樟子松纯林和山杏沙棘混交林中沙棘林带的土壤养分条件较好.     

温度对杉木林土壤呼吸的影响(英文)

Soil samples collected from the surface soil (0(10 cm) in an 88-year-old Chinese fir (Cunninghamia lanceolata) forest in Nanping, Fujian, China were incubated for 90 days at the temperatures of 15°C, 25°C and 35°C in laboratory. The soil CO2 evolution rates were measured at the incubation time of 2, 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80 and 90 days. The results showed that CO2 evolution rates of soil samples varied significantly with incubation time and temperature during the incubation period. Mean CO2 evolution rate and cumulative amount of CO2 evolution from soil were highest at 35°C, followed by those at 25°C, and 15°C. Substantial differences in CO2 evolution rate were found in Q10 values calculated for the 2nd and 90th day of incubation. The Q10 value for the average CO2 evolution rate was 2.0 at the temperature range of 15-25°C, but it decreased to 1.2 at 25- 35°C. Soil CO2 evolution rates decreased with the incubation time. The cumulative mineralized C at the end of incubation period (on the 90th day) was less than 10% of the initial C amounts prior to incubation.     

攸县3种不同水土保持林土壤抗侵蚀性能

为了研究湖南省攸县境内的不同水土保持林对土壤抗侵蚀性能的影响,本文从林地土壤的物理性状、土壤抗蚀性能和土壤抗冲性能3个方面来进行对比研究。测定其林地0~20 cm层土壤的容重、孔隙度、水稳定指数、渗透系数、土壤团聚体占土样百分比和抗冲指数几个指标,进而分析不同林分类型之间的林地土壤抗侵蚀性能的差异。结果表明:从土壤的物理性状来看,楠+桤木+枫香混交林的容重和孔隙度均比其他两种林分要好;从土壤的抗蚀性能来看,3种不同林分的水稳性指数大小按照大小顺序为楠+桤木+枫香混交林枫香+栾树+桤木混交林杉木+柏木+马尾松混交林,楠+桤木+枫香混交林的渗透性能优于杉木+柏木+马尾松混交林和枫香+栾树+桤木混交林,且3种林分的水稳性指数与渗透系数均大于荒坡地;从土壤抗冲性能来看,土壤总团聚体占土样百分比和土壤抗冲指数按照楠+桤木+枫香混交林枫香+栾树+桤木混交林杉木+柏木+马尾松混交林的大小排列顺序,且指标均大于荒坡地。     

浙江凤阳山不同林地类型土壤微生物季节动态

在浙江凤阳山自然保护区选取7个不同林地类型(常绿阔叶林、针叶林、针阔混交林、杉木林、毛竹林、柳杉林以及灌草林)采集土壤样品,分析了土壤细菌、真菌、放线菌在不同林地类型、不同土层及不同季节间的变化规律.结果表明:在不同林地类型间土壤微生物数量差异较大,三大类群微生物数量关系为细菌＞放线菌＞真菌;不同林地间,细菌数量以毛竹林土壤为最高,针叶林的最低;真菌数量以毛竹林最高,针阔混交林最低;放线菌数量以杉木林为最高,针叶林为最低.不同季节各林地土壤微生物类群数量的差异很大,其数量变化具有一定的季节性,细菌、放线菌表现出夏季＞秋季＞春季＞冬季的规律,而真菌则表现为秋季＞夏季＞春季＞冬季的规律.在土壤剖面上,随土层深度加深,土壤微生物类群数量呈现出减少的规律,表层土壤微生物含量最高.     

The value of six key soil variables for incorporation into a South African forest site classification system

The intensive nature of management practices in the exotic monoculture plantations of South Africa requires reliable decision support systems. Recent socio-economic developments, the need for optimal forest productivity, as well as increasing awareness of broader ecosystem values and environmental risks, highlight the importance of a unified approach to forest site classification and evaluation. This paper highlights the value of specific soil characteristics and its application value for a range of silviculture and management aspects related to site-specific forestry. A limited set of six soil variables are proposed for ecological mapping of forest landscapes at high-resolution operational-level scales. The variables proposed are parent material, soil classification, effective soil depth, depth limiting material, topsoil organic matter and topsoil texture. Each variable is discussed in terms of its significance as well as relevance to plantation forestry in South Africa. Shortcomings in our knowledge base and research requirements are highlighted, and the format of incorporation into a national forest site classification system is proposed. This paper will contribute to unity of purpose and understanding of forest site classification and evaluation in South Africa, and will promote management frameworks and decision support systems with desired environmental, economic and social benefits.     

不同经营模式对马尾松天然次生林土壤理化性质的影响

以慈利县二坊坪乡马尾松天然次生林为研究对象,比较其在不同经营模式下土壤理化性质的变化规律。结果表明:马尾松次生林经过1年的经营改造,Ⅱ处理(马尾松密度为900株/hm2)的土壤理化性质得到了改善,表现在土壤养分的提高,特别是土壤速效养分得到了较大的增加;而传统经营模式的土壤理化性质基本上所有指标均存在递减趋势。这说明合理的经营模式对马尾松次生林土壤肥力的维持和提高起到了积极作用,过大或过小的林分密度不利于土壤结构的改良和养分的循环与累积。     

江西安福不同类型毛竹林地土壤微生物量碳特征研究

为了掌握毛竹林地土壤微生物量碳的动态变化特征,以江西省安福林区的毛竹纯林、竹阔混交林、竹杉混交林这3种不同类型毛竹林地作为研究对象,同时以中亚热带阔叶林和杉木纯林林地为对照,对其土壤微生物量碳(SMBC)含量的季节变化情况及其在各土层的剖面分布情况进行了研究。结果表明:不同类型毛竹林地的SMBC含量间差异较大,不同类型林地0~60 cm土层的SMBC含量平均值的大小顺序为竹阔混交林(157.62 mg·kg~(-1))毛竹纯林(143.17 mg·kg~(-1))竹杉混交林(110.19 mg·kg~(-1))阔叶林(101.07 mg·kg~(-1))杉木林(86.56 mg·kg~(-1));各林分类型的SMBC含量均表现出明显的季节差异,春季的SMBC含量均极显著高于其他季节;各林分类型其SMBC含量的平均值均随土层的加深而降低,其分布在各土层的含量间的差异均达到显著水平,说明土壤表层的积聚作用明显;毛竹林地的SMBC占土壤总有机碳(TOC)的比率为1.01%~1.11%,高于阔叶林地的0.67%和杉木林的0.79%;毛竹纯林、竹阔混交林和竹杉混交林的SMBC与TOC的相关系数分别为0.71、0.55和0.47。     

Effects of aggregating forests, establishing forest road networks, and mechanization on operational efficiency and costs in a mountainous region in Japan

We investigated forest road networks and forestry operations before and after mechanization on aggregated forestry operation sites. We developed equations to estimate densities of road networks with av...     

Hydrological effects of forest litter and soil in the Simianshan Mountains in Chonging, China

A preliminary study of the hydrological effects of forest litter and soils in the Simianshan Mountains was carried out. Results indicate that the annual accumulation of different forest litters is about 6.80–20.21 t/hm² and the maximum water carrying capacity ranges from 1.8 to 4.6 mm. Among them the water carrying abilities of the litter of Lithocarpus glabra and natural deciduous forests are larger than that of Pinus massoniana. A power function relationship exists between the accumulated water-carrying volume and time. An investigation of the physical properties shows that forest soils, to a depth of 1 m, have a powerful water-carrying ability, varying from 7.84 to 18.87 mm. Non-linear regression analysis shows that the soil infiltration rate is significantly correlated with time. __________ Translated from Journal of Beijing Forestry University, 2005, 27(1): 33–37 [译自: 北京林业大学学报]     

Effects of soil moisture and temperature on CH4 oxidation and N2O emission of forest soil

IntroductionMethane (CH4) and Nitrous oxide (NZO) are tWoimportant greenhouse gases that also play an important role in photochemical reactions in atmosphere.The global warming potential of CH4 and NZO areestimated tO be about 62 and 290 times that of carbon dioxide respeCtively. The concentration of thesegases have been increasing rapidly since the start ofthe industrial age, currently at rate of about 1% and0.25% per year respeCtively (Lelieveld et al. 1993),and 70%-90% of these gases …     

Dynamics of soil carbon in a beechwood chronosequence forest

Accurate estimates of forest soil organic matter (OM) are now crucial to predictions of global C cycling. This work addresses soil C stocks and dynamics throughout a managed beechwood chronosequence (28–197 years old, Normandy, France). Throughout this rotation, we investigated the variation patterns of (i) C stocks in soil and humic epipedon, (ii) macro-morphological characteristics of humic epipedon, and (iii) mass, C content and C-to-N ratio in physical fractions of humic epipedon. The fractions isolated were large debris (>2000 μm), coarse particular OM (cPOM, 200–2000 μm), fine particular OM (fPOM, 50–200 μm) and the mineral associated OM (MaOM, <50 μm).     

Microenvironmental heterogeneity of physical soil properties in a broad-leaved Pinus koraiensis forest gap

Microenvironmental heterogeneity of soil physical properties in 0–20 cm and 20–40 cm soil layers in a broad-leaved Pinus koraiensis forest gap in Xiao Xing’anling Mountains were analyzed by geostatistical method. The results show that the amount of soil water, saturation water capacity, capillary water capacity and porosity in the top layer were greater than those in the lower layer, except for bulk density, where the opposite applied. Soil physical properties in the top soil layer had relatively higher ranges and coefficients of variation. The total and auto correlation spatial heterogeneity of soil physical properties in the top layer were larger than those in the lower layer. The soil water had a strong anisotropic structure in an easterly and northerly direction, but porosity shows isotropy in the same directions. With increasing spatial distance, the other three physical factors exhibited anisotropic structures. The mutual effect between semi-variograms of soil physical properties in the top layer within the spatial autocorrelation range was not significant. For spatial distribution of physical properties within different layers, the patches at the middle and lower ranks in the forest gap dominated. Patches at higher rank were only distributed in the 0–20 cm soil layer and were located north of the forest gap center. __________ Translated from Science of Soil and Water Conservation, 2007, 5(3): 52–58 [译自: 中国水土保持科学]