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Davide Viglietti Margherita Maggioni Enrico Bruno Ermanno Zanini Michele Freppaz 《林业研究》2013,24(4):633-642
The presence of a thick snowpack could interfere with forest stability, especially on steep slopes with potential damages for young and old stands. The study of snow gliding in forests is rather comple... 相似文献
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The chemistry of runoff waters from 13 forested watersheds in six regions (four regions from Japan, one from southern China
and one from northern Thailand) was evaluated. The Cl− concentrations in runoff waters were higher in those watersheds which had closed canopies and were nearer to the ocean. The
NO3
− concentrations were higher in those watersheds having the developed soils and high moisture conditions, but were lower in
tropical and subtropical regions for those watersheds which had high rates of nitrogen uptake and for watersheds with large
areas of saturated soils. The SO4
2− concentrations were affected by SO4
2− adsorption properties of the soils: at Shibecha, Jiulianshan, and Chiang Mai with high adsorption capacities SO4
2− concentrations in streams were low. High SO4
2− concentrations were found at Mt. Hiei and Kagawa due to the weathering of sulfur minerals and high levels of atmospheric
sulfur deposition. Within regions SO4
2− concentrations were inversely related to NO3
− concentrations. A comparison among the watersheds suggested H+ consumption in deeper soil that increased pH and HCO3
− concentrations of the runoff waters of some watersheds. Anion concentrations increased with low H.I. (Humidity Index) values
suggesting that dry conditions increased concentrations due to high rates of evapotranspiration. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1-4):127-140
Soil water and temperature measurements were made at a clearcutting in Jädraås, central Sweden, to give appropriate information for nutrient flow calculations and soil biological research. Compared to uncovered plots, slash‐covered plots were 1–2°C colder and had 3–6 volume percent higher water content in the 5 cm thick humus‐layer during the growing season following cutting. Relative to air, soil temperatures became warmer at both treatments during the second season and differences between uncovered and covered plots decreased. Tension dynamics in the mineral soil was most pronounced in uncovered plots, especially during the first dry growing season. The physically based model, SOIL, was used to analyse these observations and to estimate the effects of clearcutting. Simulated snow and frost depths, soil temperatures, water contents and tensions as well as ground water table were compared with measured data during a period of one to four years. Physical parameter values were estimated from independent measurements and by subjective optimization. Simulated soil water dynamics revealed the importance of hysteresis and vapour flows in sandy forest soils. The hydrological clearcutting effect as estimated from mature Scots pine evapotranspiration properties showed a 50% reduction of evapotranspiration, an increased soil water storage (0–1 m) of up to 120 mm and an increased percolation of 125 mm per year. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1-4):289-304
Soil water characteristics were determined in 6 soil profiles along a Norway spruce forested sandy‐loamy till hillslope in Southern and Northern Sweden, respectively. The soil moisture class was mesic at both sites, i.e. having well drained soil water conditions. Two different Podzols; Leptic and Orthic, were developed at each site respectively. The vertical distribution of soil water retention capacity (SWRC) was similar in the different profiles at each site respectively. The SWRC of the mineral soil was significantly higher in the spodic B horizon compared to the other horizons. In concordance with the vertical distribution of SWRC, the largest amount of organic matter in the mineral soil, measured as ignition loss, was also found in the spodic B horizon. The significantly higher SWRC in the spodic B horizon, i.e. the ¡lluvial horizon, was suggested to depend on the accumulated organic‐sesquioxide material in this horizon. As SWRC reached maximum values in the spodic B horizon at all tensions applied, it was further suggested that soil formation in the studied profiles enhanced the formation of both micro‐ and macropores in the spodic B horizon. The variation of SWRC, at a certain level in the soil, was often larger within a profile than between the profiles at each site respectively. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(8):762-773
Abstract Stump harvest in forests can cause both reductions of CO2 emissions through a decrease of decomposable substrate (direct effect) and emission increases as a consequence of deep and extensive soil disturbance (indirect effect). Here, the effects of stump harvest on net ecosystem CO2 exchange (NEE) in a former Norway spruce stand in mid Sweden are presented. CO2 exchange was continuously followed by eddy-covariance measurements during the first years after harvest. Differences in NEE from stump harvested and mounded (reference) plots were determined by soil-surface respiration measurements. Respiration from decaying stumps was estimated by a decomposition model. Fluxes indicated a direct effect (decreased efflux) during the first year after harvest that corresponded to the absence of decomposing stumps. During the following years, this emission reduction was increasingly counteracted by an indirect effect (increased efflux) of similar magnitude. This means that the expected emissions caused by extra soil disturbance occur with a certain delay and seem to increase with time. By these emissions, the substitution efficiency of stumps as bioenergy resource is reduced. Furthermore, at a time scale of centuries, instant combustion of stumps leads to a larger contribution to global warming than slow decomposition, because the stump carbon is available earlier in form of greenhouse gas. This is estimated by the time integral of emissions. Thus, despite the surprisingly low initial emissions, the overall substitution efficiency and climate benefits of stump harvest are likely to be small. The long-term consequences of stump harvest for the carbon budget are, however, still uncertain. 相似文献
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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。 相似文献
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Ken'ichirou Kosugi 《Journal of Forest Research》1997,2(1):1-8
The soil water retention model proposed by Kosugi was modified to have a relatively simple functional form. The resulting
water retention model (the lognormal distribution model) contains two parameters which have physical significance on the water
retention curve and are related directly to the statistics of the soil pore radius distribution functiong(r). The observed retention data sets of 282 undisturbed forest soils taken from Mashimo were analyzed using the lognormal distribution
model, and it was shown that the model performs fairly well for every data set. The estimated parameters of the model indicated
that the water retention characteristics of the undisturbed forest soils are related to the soil structure more closely than
to the soil texture. Many crumb-structure forest soils have greater median ofg(r) than the crumb and granular-structure soils. Disturbed loamy soils have smaller median ofg(r) than many of the undisturbed forest soils and disturbed sandy soils have smallerg(r) width than the forest soils. The brown forest soils taken from A-horizon generally have the greater median ofg(r) than the brown forest soils taken from B-horizon. Some of the brown forest soils have the greater width ofg(r) than the black soils. The median ofg(r) of brown forest soil taken from A-horizon generally becomes greater as the soil moisture condition becomes wet. 相似文献
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RESEARCHAPPRoACHESAccordingtoresearchscales,weadapttwokindsofresearchmethods.Onthelargcrscale,wedefmethcboundariesofresearchsystCmsaccordingtothewatCrshedsorbasins,andthenresearchontherelationshipbctWeentheinputs(PreCipitation)andoutPuts(streaInflow)andonthermuencesofallkindsofnatUralmpPhiFalfactorsandartfficialdisturban9esreqardingtheintemalsystemsasblackboxes.'onthesmallerscale,accordingtovegetationtyPes,weestablishrunoffplotSandcorrespondinginstallationsinthemainforesttyPeQfvirg… 相似文献
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Xiang Li Jian-zhi Niu Jiao Li Bao-yuan Xie Yi-ni Han Jing-ping Tan Ying-hu Zhang 《林业研究》2012,23(3):419-424
We studied the impact of forest vegetation on soil erosion,surface runoff, and sediment generation by using field simulated rainfall apparatus. We measured runoff and sediment generation of five 4.5 × 2.1m runoff plots (a bare soil as a control; two Pinus tabulaeformis forestplots and two Platycladus orientalis forest with row spacing of 1 m × 1m and 1.5 m × 1.5 m, respectively) in Beijing Jiu Feng National ForestPark under three rainfall intensities (0.42, 0.83, 1.26 mm per minute).Forest vegetation significantly reduced soil erosion and sediment yield.Mean total runoff volume in the four tree stand plots was 93% of that inthe control plot, demonstrating the limited effectiveness of forest vegetation in runoff control. With increasing rainfall intensity, runoff reductionin forest plots declined from 28.32% to 2.1%. Similar trends in runoff coefficient and the relationship between runoff volume and rainfall duration was observed. Mean total sediment yield and mean sediment yield reduction rate under different treatments was 55.05% and 43.17% of those in the bare soil control plot, respectively. Rainfall intensity playedan important role in runoff and sediment generation processes, and had agreater impact on runoff than on soil erosion and sediment generation.When considering several factors in runoff and sediment transport processes, the P. tabulae form plot with row spacing at 1 × 1 m had a greater effect on soil and water conservation than did other forested plots. 相似文献
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France Goulet 《New Forests》1995,9(1):67-94
Soil frost heaving is the result of the formation of ice lenses in the soil caused by a segregation of the soil water. Ice lenses are growing from below and pushed upward. Seedlings heave when they are pushed out of the ground by the ice sheet formed at the surface of the soil. Frost heaving may greatly reduce growth and survival of forest tree seedlings particularly in regions where freezing and thawing are accompanied by high soil moisture. Resistance to frost heaving increases with size of seedling as the ability of a seedling to anchor itself increases. A few methods, such as fertilizing, choice of planting spots, sowing or planting at the proper time, shading, and use of mulches, appear to be effective in controlling frost heaving. Shade from natural plant cover can greatly reduce frost heaving. 相似文献
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One of the main concerns of afforestation with exotic fast-growing species is their higher soil water consumption compared with the native vegetation they replace. In this regard, sites downstream of the plantations may suffer temporal or permanent droughts. Under this hypotheses, soil water use of Douglas-fir (Pseudotsuga menziesii) plantations and natural woodlands or shrublands (“ñirantales”) was evaluated in two sites during two growing seasons in El Foyel Valley (Río Negro province), Patagonia Argentina. Two methodological approaches were applied: water balances and sapflow measurements. Douglas-fir forests doubled the leaf area index (LAI) of the native forests (12.6 and 5.1 m2 m?2, respectively). Methodological problems were found while constructing water balances because a non-quantified influx of water to the soil was detected in all systems at the beginning and end of the growing season. This flux was not in correlation with precipitation input demonstrating the geological complexity of the valley. For this reason, caution has to be paid to water balance results. However, we have confidence on sapflow measurements, which indicated, as suggested by the water balances, that there are no differences in transpiration between systems (average of 4.8–3.6 mm day?1 for the exotic and native forests, respectively) in spite of Douglas-fir plantations having twofold LAI than native ñirantales. However, a different response of transpiration to atmospheric demand was found between the exotic and native species, suggesting differences in their ecophysiological characteristics. 相似文献
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Zane Kalvīte Zane Lībiete Ivars Kļaviņš Arta Bārdule Kārlis Bičkovskis 《Scandinavian Journal of Forest Research》2021,36(1):1-14
ABSTRACT Despite near-extinction in the nineteenth century, after efficient restoration measures the population of Eurasian beaver (Castor fiber L.) in Latvia currently is viable and growing. While the ecological effect of the species on water quality and biodiversity is generally positive, the high number of animals in production forests often creates challenges for management. Drainage ditches are among the most favoured habitats of beavers resulting in flooded stands, reduced tree growth and economical losses. The aim of the study was to evaluate the chemical properties of water in forest drainage ditches, affected by beaver activity, and their changes after the dam removal. Chemical composition of surface water in ditches was analysed in sampling points above dam, below dam and in the ditch itself after removal of the dam; results compared to pristine beaver site nearby on a small stream. Results did not show significant differences between concentrations above and below dams. After removal of the dams, significant increase in DOC, N-NO3 -, N-NH4 + and TSS concentrations and significant decrease in TP concentrations were observed in some of the sites. Observed concentrations of all measured parameters were significantly lower in pristine beaver site than in beaver sites on drainage ditches. 相似文献
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The soil water balance technique was used to study evaporation from two fodder tree species, tenEucalyptus species and annual pasture over a three year period after planting in the Western Australian wheatbelt. Evaporation is the total water loss by the processes of transpiration, evaporation from the soil surface and evaporation of water intercepted by plant canopies.Evaporation from both fodder trees and from seven of theEucalyptus species was greater than from pasture for one or more of the study years. The maximum difference in evaporation between trees and pasture was 82, 84 and 70 mm in the first, second and third study years, respectively. Higher evaporation from trees was associated with greater depletions in soil water than occurred beneath pasture. Upward movement of water from wet soil beneath the root zone was found under trees, with a maximum flux of 30 mm observed over a one year period beneathE. camaldulensis.The water use efficiency of fodder trees was significantly higher than for mostEucalyptus species, due to greater yields from fodder trees. Biomass production was found to be a good indicator of the water use of eucalypts over the first two years of growth, but the relationship between productivity and water use was found to differ for species with tree and mallee forms. In the third year of study, obvious differences in the relation between water use and yield were observed for some species of eucalypts with high evaporation. 相似文献