Simulation of soil water dynamics in a Caragana intermedia woodland in Huangfuchuan watershed

As vegetation coverage increases, soil water content can decrease due to water uptake and evapotranspiration. At a very high level of plant density, poor growth and even mortality can occur due to the decrease of soil water content. Hence, a better understanding of the relationship between soil water content and the density of plants is important to design effective restoration projects. To study these relationships, we developed a soil water dynamic simulation model of a Caragana intermedia woodland under different slope gradient and slope aspect conditions in the Huangfuchuan watershed on the basis of the previous studies and field experiments. The model took into account the major processes that address the relationships of plants and the environment, including soil characteristics, precipitation, infiltration, vegetation transpiration, and soil evaporation. Daily changes in soil water content, transpiration, and evaporation of the Caragana intermedia woodland with different vegetation coverage, slope gradient, and slope aspect were simulated from 1971 to 2000. Based on the model simulations, we determined the functional relationships among soil water content, plant coverage and slope as well as the optimal plant density on flat slopes. We also determined the effects of slope gradient and slope aspect on soil water content. When slope gradient was less than 10°, the optimal plant density was sensitive to slope gradient. In the slope range from 10° to 30°, plant density was not sensitive to slope gradient. Therefore, it is important to consider planting densities on the hillsides with slope gradients less than 10° for reconstructing vegetation. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(6): 910–917 [译自: 植物生态学报]     

Effects of site conditions and methods of cultivation on growth of sawtooth oak plantations

The effects of site conditions and cultivation on the growth of sawtooth oak (Quercus acutissima Carr.) plantations were evaluated at the Hongyashan forest farm, in Chuzhou City, Anhui Province, China. The results indicate that the position on the slope, the amount of gravel and the thickness of the soil were important factors in the growth of the sawtooth oak. Lower slope positions with small amounts of gravel and a thick soil were better for the growth of this species than middle slope positions with more gravel and a thin soil. Given the site conditions of the hilly and mountainous areas in Chuzhou City, the mixed Chinese fir (Cunninghamia lanceolata Hook.) and sawtooth oak forests did not improve forest productivity compared with pure sawtooth oak forests. Both urea and compound fertilizers promoted the growth of sawtooth oak, as did site preparation and intercropping. Two years after planting, the height growth of ordinary seedlings with a starting height of 0.6 m was higher than that of supper seedlings with a starting height of 1.0 m. Compared with planting, the early growth of the coppices was faster, but the later growth of the coppices was slower. __________ Translated from Journal of Fujian College of Forestry, 2008, 28(2): 130–135 [译自: 福建林学院学报]     

Effects of solid water and foliar fertilizer on survival and growth of seedlings in sand prevention and control

To promote afforestation in sandy lands and increase the effects of prevention and control of desertification, the application of a new drought-resistant product—solid water and foliar fertilizer “Shifengle”—was studied. A comparison of three treatments (solid water, foliar fertilizer, and control) showed that both solid water and foliar fertilizer increased plant survival rate by 10% and 18.2%, respectively. Afforestation survival rates of Salix psammophila and Hedysarum mongolicum reached over 90%. In addition, height and crown growth as well as biomass of seedlings were improved by the treatments. __________ Translated from Journal of Beijing Forestry University, 2006, 28(3): 76–80 [译自: 北京林业大学学报]     

Rapid changes of soil properties following Caragana korshinski plantations in the hilly-gully Loess Plateau

In the semi-arid area of the Loess Plateau, Caragana korshinski, a leguminous shrub, is the dominant plant species widely used in vegetation rehabilitation programs. We collected soil samples in 8-and 18-year-old C. korshinski plantations to assess the effects of the shrub on the physical and chemical properties of the soil as well as enzyme activities. Soil samples were taken from two depths (0–20 and 20–40 cm) under the shrub canopy between shrubs. Results showed that shrub rehabilitation and development enhanced accumulation of organic C and total N. Carbon and nitrogen concentrations increased significantly with plantation age and had increased by 15.3–20.5-fold and 11.1–13.6-fold at 0–20 cm depth at the 18-year-old plantation compared with farmland soil. It was found that C. korshinski contributed significant enrichment of C and N contents under their canopies compared with farmland. The content of water stable aggregates in 18-year-old shrub land soil is higher than the 8-year-old shrub land, and the big aggregates (>5 mm) increased for the most part, by 67.4% and 59.0% in different layers, respectively. The contents of aggregates of over 0.25 mm in two shrub land soils in the upper layer (0–20 cm) increased by 4.6% and 14.1% compared with farmland. It indicates that C. korshinski afforestation can increase the content of aggregates. C. korshinski plantation can accelerate the increase of soil urea activity and invertase activity, respectively, especially in the upper layer. __________ Translated from Scientia Silvae Sinicae, 2006, 42(1): 70–74 [译自: 林业科学, 2006, 42(1): 70–74]     

地形因子对思茅松人工林土壤有机碳储量的影响

[目的]以思茅松人工中龄林为研究对象,探讨不同坡向、坡度和坡位对思茅松人工林SOC储量的影响,为精确评估思茅松人工林碳储量提供科学依据。[方法]对不同坡向、坡度和坡位不同土壤层次的SOC含量、全氮、土壤密度、C:N和SOC储量进行T检验和单因素方差分析,对不同土层的SOC储量和全氮、土壤密度、C:N之间进行Pearson相关分析。[结果]思茅松人工中龄林,SOC含量、全氮和C:N随着土层加深而减少,土壤密度随着土层加深而增加。不同的坡向和坡度显著影响SOC储量大小,阳坡的SOC储量要显著高于阴坡,坡度为20 30°的SOC储量要显著低于10 20°和0 10°,坡位对SOC储量大小无显著影响。在0 100 cm土层中,随着土层深度的增加,不同立地条件的思茅松人工中龄林的SOC储量呈减小趋势,不同坡向、坡位和坡度0 20 cm土层SOC储量均显著高于其它土层。坡向和坡度显著影响0 20 cm土层的SOC储量(P0.05);坡位对各层SOC储量均无显著影响(P0.05)。0 20 cm土层中SOC储量和土壤密度呈极显著负相关,和坡向、坡度呈显著负相关关系;除2040 cm土层外,其它土层的SOC储量与全氮之间呈极显著正相关;SOC储量和坡位与C:N在任一土层均无显著相关关系。[结论]立地条件差异影响SOC储量的大小与分布,尤其是坡向和坡度的不同会造成思茅松人工中龄林SOC储量的差异。     

Factors affecting distribution of microbiotic crusts in the grain-for-green land of the loess region, northern Shaanxi, China

A field survey was conducted in the grain-forgreen land of the loess region, northern Shaanxi, China, from July to August of 2005 to provide a scientific evaluation of the grain-for-green project, including its soil and water conservation and other ecological benefits for the region. The distribution of microbiotic crusts were studied, while human disturbance, aspect, topography, vegetation structure and other factors affecting it were obtained from the analysis of survey data from 78 sample plots. Results show that crust coverage is larger on less-disturbed plots than on highly-disturbed ones, on north-facing plots than on south-facing ones and on gully-slopes than on ridge-slopes. Coverage increases with herbal coverage and trees can provide better conditions for distribution of crusts than shrubs. Therefore, crust coverage is larger in herb-dominated plots than in tree-dominated ones and crusts in shrub-dominated plots are smaller. However, we made no progress in our study on deciding how slope degrees and herb species affect the distribution of crusts. We believe that more studies are necessary for a further exploration of the relationship between them. __________ Translated from Journal of Beijing Forestry University, 2007, 29(1): 102–107 [译自: 北京林业大学学报]     

Impacts of fractal features of soil on moisture infiltration capacity of typical stands in Jinyun mountain of Chongqing city

The soil structure was expressed with fractal dimensions of particle size distribution (PSD), aggregate size distribution (ASD), and soil pore size distribution (SPD). The effect of soil fractal features on soil infiltration velocity and process was studied. The result of the fractal feature shows that fractal dimensions of PSD are obviously greater than those of ASD and SPD, and in different soil genetic horizons, the fractal dimension of ASD has the greatest variability, and shows a downtrend on the top-to-bottom genetic horizon. According to the soil infiltration process curve, the infiltration process was divided into three phases: (1) the initial phase (0–5 min), (2) the transition phase (5–30 min), and (3) the stable phase (30–180 min). In the initial phase of infiltration, the soil structure of soil genetic horizon A was the major influencing factor; in the transition phase of infiltration, the pore distribution of soil horizon AB and soil structure of horizon B were the major influencing factors; in the stable phase of infiltration, the soil structure of horizon C was the major influencing factor to the infiltration velocity. Soil infiltration process is influenced comprehensively by soil PSD, ASD, and SPD. In the overall soil water infiltration, the infiltration in shrub forest land was much faster than that in other land uses, and in the initial infiltration phase, arable land soil infiltration was much faster than that in forest land, and in the stable infiltration phase, the infiltration velocity in forest land was faster than that in arable land. __________ Translated from Journal of Beijing Forestry University, 2006, 28(3): 73–78 [译自: 北京林业大学学报]     

Photosynthetic physio-response of Taxodium ascendens seedlings to different soil water gradients

Four different kinds of water treatments were applied to study the photosynthetic eco-physiological characteristics of Taxodium ascendens seedlings in the environment of the Three Gorges hydro-fluctuation belt. The four kinds of water treatments were: normal growth water condition (CK), light drought stress (T1), soil water saturation (T2), and soil submersion (T3). The results showed that different water treatments could effectively influence the content of the photosynthetic pigment, leaf gas exchange and apparent resources use efficiency of T. ascendens seedlings. It was also demonstrated that the T. ascendens seedlings could not only tolerate water submersion and wet conditions but also endure a certain degree of drought. To establish a protection forest system in the hydro-fluctuation belt in the Three Gorges Reservoir Area, the species T. ascendens is suitable for planting in conditions of root submersion or water-saturated soil. In case it is planted in drought conditions, this tree species should be watered appropriately in order to keep its normal net photosynthetic rate. Translated from Forest Research, 2006, 19(1): 54–60 [译自: 林业科学研究]     

Effect of tree-crop intercropping on a young Populus tomentosa plantation

In order to study the effect of tree crop intercropping on a young plantation of Populus tomentosa in the plains along the Yellow River, field experiments were conducted by observing the growth of the plantation, the nutrient content in leaves, the nutrient and water content in the soil, and the output of crops. The relationship between forest growth and nutrient content in the tree leaves and the soil were analyzed. Results show that tree crop intercropping in young plantations can not only improve soil water content, but also enhance the contents of organic matter and the available nitrogen, phosphorus and potassium in soil resulting in the vigorous growth of the individual trees. Diameter at breast height (DBH) was positively related to the contents of organic matter in the soil, and the contents of N, P and K in the tree leaves had correlation coefficients of 0.967, 0.955, 0.988 and 0.972, respectively. Whole tree leaf area, crown width, number of branches and the mean length of branches in the intercropped plantation (intercropped with watermelon and vegetables, peanut and winter wheat, and soybean) were, respectively, 1.70–3.0 times, 2.22–2.47 times, 1.0–1.41 times and 1.70–2.32 times of those of CK (without intercropping). Diameter at breast height (DBH) and tree height in the intercropped plantation were 50.5%–136.7% and 27%–59.5% higher than those of the CK, respectively. The study also showed that intercropping with watermelon and vegetables proved to have the highest economic return among the treatments adopted. Tree crop intercropping in young plantations is an effective measure to increase forest growth and economic benefit. __________ Translated from Journal of Beijing Forestry University, 2006, 28(3): 81–85 [译自: 北京林业大学学报]     

A weeding-duration model for <Emphasis Type="Italic">Larix kaempferi</Emphasis> plantations in Hokkaido,northern Japan

In this study, a weeding-duration model for Larix kaempferi plantations was developed that employs a generalized linear model. The number of years that weeding is necessary is the response variable, and elevation, slope, maximum snow depth, annual precipitation, geological type, soil type, site index, slope aspect, and vegetation type are explanatory variables. Among the explanatory variables, geological type, soil type, slope aspect, and vegetation type are categorical data. We assumed a Poisson distribution for the response variable. The link function was log. Among the models that could be developed from these variables, we chose the model with the smallest Akaike’s information criterion (AIC). The weeding-duration model can be written as follows: years that weeding is necessary = Exp (−0.0172833 × site index + 0.0014053 × maximum snow depth (cm) + 1.7417731). The results of this study imply that weeding of Larix kaempferi plantations is needed for more years as the maximum snow depth increases and fewer years as the site index increases. This model is useful for cost–benefit analyses of afforestation or reforestation with Larix kaempferi.     

Hygrothermal effect of bamboo by dynamic mechanical analysis

Dynamic properties of bamboo, Phyllostachys pubescens, with moisture content (MC) ranging from −130 to 130°C, were studied by dynamic mechanical analysis (DMA). The results showed that the hygrothermal effect on dynamic mechanical properties was negative. The storage modulus decreases with increasing temperature and MC, and glass transition temperature decreases with increasing MC. The glass transition temperature and tan delta of bamboo were 30.5°C, 0.02 and 10.61°C, 0.04, when MC was 10% and 34%, respectively. __________ Translated from Journal of Nanjing Forestry University (Natural Sciences Edition), 2006, 30(1): 65–68 [译自: 南京林业大学学报(自然科学版), 2006, 30(1): 65–68]     

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]     

Response of pine forest to disturbance of pine wood nematode with interpretative structural model

Pine wood nematode (PWN, Bursaphelenchus xylophilus), originating from North America, causes destructive pine wilt disease. Different pine forest ecosystems have different resistances to B. xylophilus, and after its invasion, the resilience and restoration direction of different ecosystems also varies. In this study, an interpretative structural model was applied for analyzing the response of pine forest ecosystem to PWN disturbance. The result showed that a five-degree multi-stage hierarchical system affected the response of the pine forest ecosystem to PWN disturbance, in which direct affecting factors are resistance and resilience. Furthermore, the analysis to the 2nd, 3rd and 4th degree factors showed that not only does distribution pattern of plant species and pine’s ecological features affect the resistance of pine forests’ ecosystem, but removal of attacked trees and other measures also influence the resistance through indirectly affecting the damage degree of Monochamus alternatus and distribution pattern of plant species. As for resilience, it is influenced directly by soil factors, hydrology, surrounding species provenance and biological characteristics of the second and jointly dominant species, and the climate factors can also have a direct or indirect effect on it by affecting the above factors. Among the fifth elements, the elevation, gradient and slope direction, topographical factors, diversity of geographical location and improvement of prevention technology all influence the response of pine forest ecosystem to PWN disturbance. __________ Translated from Scientia Silvae Sinicae, 2007, 43(8): 85–90 [译自: 林业科学]     

Aspirated pits in wetwood and micromorphology of microbial degradation in subalpine fir

Differentiating from normal wood, pit membranes in wetwood of subalpine fir contain bacteria of water drop shape or orbicular shape, and flaky shape, as observed using Scanning Electronic Microscope. Not only are ray parenchyma cells in wetwood partially degraded but also margo strands in pit membranes are somewhat degraded by bacterial activities. Most of the bordered-pit membranes in normal wood are unaspirated in green conditions and the proportions of aspirated pits in earlywood and latewood account for only 6.8% and 13.4%, respectively. Nevertheless, most of the bordered-pit membranes in wetwood are aspirated in green conditions and the proportions of aspirated pits account for 77.7% and 72.1%, respectively. The problem of hard-to-dry for subalpine fir could be reasoned from the considerable amount of aspirated pit membranes in wetwood. __________ Translated from Journal of Nanjing Forestry University (National Science Edition), 2006, 30(1): 53–56 [译自: 南京林业大学学报 (自然科学版), 2006, 30(1): 53–56]     

Relationship between landslides and lithology in the Three Gorges Reservoir area based on GIS and information value model

Development of landslides in the Three Gorges Reservoir area is related to many factors. Lithology is one of the indispensable internal factors, besides relative height differences, slope gradients and slope profiles. We used an information value model with geographical information system (GIS) technology to study how lithology contributes to the development of landslides from the Yunyang to Wushan segment in the Three Gorges Reservoir area and we quantify the relationship between lithology and development of landslides. Via an investigation of 205 examples of past landslides, we found that the lithology of J_3s, J_3p and T_2b contributes most. Our research results can provide a valid basis for future construction in the Three Gorges Reservoir area. __________ Translated from Journal of Beijing Forestry University, 2007, 29(6): 138–142 [译自: 北京林业大学学报]     

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]     

Effect of conversion of farmland to forest or grassland on soil erosion intensity changes in Yanhe River Basin, Loess Plateau of China

Dynamic changes of soil erosion affected by conversion of farmland to forest or grassland in the Yanhe River Basin were analyzed based on the revised universal soil loss equation (RUSLE). The RUSLE variables were selected and calculated reasonably using the GIS technique. Results show that: 1) After the conversion of farmland to forest or grassland, soil erosion decreased greatly. Compared with soil erosion in period of 1986 to 1997, the soil erosion amount had been reduced on the average by 30.6% by 2000; 2) Of the different land uses, slope farmland, especially the steep slope land had the greatest impact on soil erosion. The conversion of forest or grassland was the main driving force for the reduction of soil erosion; 3) In the short term, soil erosion was mainly controlled by C-factor, implying that the adjustment of land use structure might be an effective approach to reduce soil erosion. __________ Translated from Science of Soil and Water Conversation, 2007, 5(4): 27–33 [译自: 中国水土保持科学]     

Characteristics of carbon and nitrogen of soil microbial biomass and their relationships with soil nutrients in Cunninghamia lanceolata plantations

The soil microbial biomass and nutrient status under the native broadleaved forest and Cunninghamia lanceolata plantations at the Huitong National Research Station of Forest Ecosystem (in Hunan Province, midland of China) were examined in this study. The results showed that after the native broadleaved forest was replaced by mono-cultured C. lanceolata or C. lanceolata, soil microbial biomass and nutrient pool decreased significantly. In the 0–10 cm soil layer, the concentrations of soil microbial carbon and nitrogen in the broadleaved forest were 800.5 and 84.5 mg/kg, respectively. These were 1.90 and 1.03 times as much as those in the first rotation of the C. lanceolata plantation, and 2.16 and 1.27 times as much as those in the second rotation of the plantation, respectively. While in the 10–20 cm soil layer, the microbial carbon and nitrogen in the broadleaved forest were 475.4 and 63.3 mg/kg, respectively. These were 1.86 and 1.60 times as much as those in the first rotation, and 2.11 and 1.76 times as much as those in the second rotation, respectively. Soil nutrient pools, such as total nitrogen, total potassium, NH₄ ⁺-N, and available potassium, also declined after the C. lanceolata plantation replaced the native broadleaved forest, or Chinese fir was planted continuously. Less litter and slower decay rate in pure Chinese fir plantation were the crucial factors leading to the decrease of soil microbial biomass and nutrient pool in this area. Human disturbance, especially slash-burning and site preparation, was another factor leading to the decrease. There were significant positive correlations between soil microbial carbon and nitrogen and soil nutrients. To improve soil quality and maintain sustainable productivity, some measures, including planting mixed conifer with hardwood, preserving residues after harvest, and adopting scientific site preparation, should be taken. Translated from Chinese Journal of Applied Ecology, 2006, 17(12): 2,292–2,296 [译自: 应用生态学报]     

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]     

Water consumption of a single tree from the main afforestation tree species in Western Shanxi Province, a loess area

Water is the key factor in vegetation growth in a loess area. Researchers have been keen on the study of tree transpiration for a long time. To provide a scientific basis and practical instruction for vegetation reconstruction and recovery in a loess area, the paper measured and calculated the water consumption of potted Platycladus orientalis, Robinia pseudoacacia, Armeniaca vulgaris and Pyrus hopeiensis separately during the growing season (from Apr. to Nov.). The four were the main afforestation species in a loess area of western Shanxi based on the principle of water balance. Using data on soil water dynamics and the range of available moisture on potted mature trees, the relationship between water supply and consumption and soil moisture availability and deficit state were analyzed. Several conclusions are listed as follows: 1) In the dry year (2002), during the growing season the precipitation was 430.7 mm and the water consumption of potted trees was from 430 to 490 mm. More water consumption and less available water supply occurred, showing a serious water deficiency. In the rainfall-rich year (2003), during the growing season the precipitation was 870.2 mm and the water consumption of potted trees was from 480 to 515 mm. Due to the uneven distribution of rainfall, the water budget balance was slightly affected in May and November. 2) The curves of soil water content of different species had similar annual changes, although the trends were different in the same month, and those of the same tree species in different test plots also had different trends in the same month. 3) Non-available soil water content of Platycladus orientalis, Robinia pseudoacacia, Armeniaca vulgaris and Pyrus hopeiensis was less than 8.0%, 8.4%, 9.2% and 9.7% respectively, which indicated that Pyrus orentalis used water more efficiently than the others. In the dry year (2002), for several months, soil water content of potted trees was lower than its threshold value for non-available soil water content, which could influence the healthy growth of trees. After supplements of precipitation of winter in the year and spring in the next year, soil water content was higher than the lower limit of soil readily available moisture content, which implied that a balance between inter-annual water supply and consumption could be maintained. __________ Translated from Scientia Silvae Sinicae, 2006, 42(9): 18–23 [译自: 林业科学]