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The effects of clear-cutting on the decomposition rate of leaf litter and on nitrogen (N) and lignin dynamics were investigated
in a temperate secondary forest. Decomposition processes were examined over an 18-month period by the litterbag method and
compared between a clear-cut site and an adjacent uncut control site using leaf litter from five dominant tree species (Clethra barvinervis, Quercus serrata, Camellia japonica, Ilex pedunculosa and Pinus densiflora). The decomposition rate for litter from C. barvinervis, Q. serrata and I. pedunculosa was significantly greater in the clear-cut plot than in the control plot, and there was no significant difference between
plots for C. japonica and P. densiflora. Water content of litter was consistently lower in the clear-cut plot than in the control plot. Nitrogen mass increased after
6 months in the control plot, whereas no net increase of N was observed in the clear-cut plot. Nitrogen concentration increased
with respect to accumulated mass loss of litter and was consistently lower in the clear-cut plot for all five species. The
mass of lignin remaining in decomposing litter was generally lower in the clear-cut plot, but lignin concentration in decomposing
litter was not significantly different between the clear-cut and control plots. 相似文献
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Åke Berg Karin Ahrné Erik Öckinger Roger Svensson Bo Söderström 《Biological conservation》2011,144(12):2819-2831
Remaining patches of semi-natural grasslands are hot spots for biodiversity in modern agricultural landscapes. In Sweden semi-natural pastures cover approximately 500,000 ha. However, power-line corridors, road verges and clear-cuts cover larger areas (in total about 2,000,000 ha), and these open, less intensively managed habitats are potentially important for species associated with taller vegetation and flower resources (e.g. pollinating insects). The aim of the present study was to evaluate the relative importance of semi-natural pastures and the other three open habitats for butterflies in 12 forest-farmland mosaic landscapes in south central Sweden. Species composition differed significantly between habitats in multivariate analyses. Power-line corridors and semi-natural pastures harbored several species that were disproportionally abundant in these habitats (13 and 8 species, respectively), and power-line corridors also harbored several species that were classified as typical in indicator species analyses. There were more butterfly species, higher abundances and a tendency for more individuals of red-listed species in power-line corridors than in the other three habitats. Effects of the surrounding landscape composition seemed to be weaker than that of the local habitat. However, species composition was significantly associated with landscape composition and species with intermediate and low mobility were more abundant in forested landscapes than in landscapes dominated by arable fields. Analyses of flying time and host plants for larvae suggest that early flying species and species associated with dwarf shrubs were more common in power-line corridors than in the other habitats. A landscape perspective, which takes several habitats into account, is needed for conservation of butterfly communities in forest-farmland landscapes. Power-line corridors and road verges offer possibilities for creating habitats that are suitable for pollinating insects through conservation-oriented management. 相似文献
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Selection of appropriate aquatic habitat indicators is important for supporting sustainable forest and watershed management. To date, many identified watershed indicators have not been well tested. To address this issue, we sampled 28 stream reaches in the central and south interior of British Columbia, Canada. The selected reaches were similar with respect to gradient, watershed and topographic characteristics but with various levels of forest harvesting. Aquatic habitat indicators were derived based on a field survey, involving substrates, channel dimensions, pools, and large woody debris (LWD), together with some ratios and derivatives generated from them. Timber harvest disturbance at the watershed scale was quantified by calculating historical forest clear-cut area based on the BC vegetation resources inventory database. To account for the subsequent forest recovery, equivalent clear-cut area (ECA) was calculated based on the dominant species of each stream watershed and its regrowth since being logged. Pearson correlation coefficients showed that percent ECA and percent historical clear-cut area could effectively quantify the cumulative logging disturbance by limiting the effect of factors not related to logging activity (i.e., watershed area and elevations). These two variables were then related to the aquatic habitat indicators. Pearson correlation analyses found that relative width (ratio of D to bankfull width) (D is the b axis diameter of the largest substrate particle found in the reach), relative roughness (ratio of D to bankfull depth), pool frequency and per piece LWD volume are sensitive to percent ECA, i.e., significant (p < 0.01) while independent of influence from non-forest logging activity related factors and spatial clustering of samples. This relationship also holds true for the last two indicators when related to percent historical clear-cut area, though with a reduced degree of correlation. In addition, mean LWD diameter also showed significant relationship with percent historical clear-cut area, but not with percent ECA. Overall, per piece LWD volume was considered as the best aquatic habitat indicator. The performance of mean LWD diameter was comparable to per piece LWD volume if percent historical clear-cut area was used to quantify forest disturbance. Implications of these findings for forest management strategies are discussed. 相似文献
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Carbon stocks and stock changes in a chronosequence of 24 red spruce (Picea rubens Sarg.) dominated stands in Nova Scotia, Canada, were compared against predictions from the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3). Regression analysis of the observed versus simulated total ecosystem C stocks indicates the model's predictions accounted for 81.1% of the variation in the observed biomass data and for 63.2% of the variation in total ecosystem C data; however, the simultaneous F-test for bias was significant. Discrepancy between the observed and simulated total ecosystem C data was primarily caused by differences in dead organic matter C pool estimates, with the model consistently predicting higher soil C throughout stand development. Changes to model parameters were not warranted however, as the field data measured only a portion of the mineral soil profile represented in the model.
Clear-cut and partial-cut harvesting scenarios for red spruce stands were simulated to examine the impacts of clear-cut and partial-cut harvesting on C stocks. Total ecosystem C increased in the partial-cut stand throughout the 240-year simulation from 308.9 to 327.3 Mg C ha−1, while it decreased in the clear-cut stand to 305.8 Mg C ha−1. Enhanced C sequestration in the partial-cut stand was a consequence of the residual standing biomass providing a continuous source of litterfall and reducing decomposition rates of the forest floor. Choice of harvest system clearly affects forest ecosystem C stocks, but also affects the amount of C removed from forests to meet society's needs. Over the period of the simulation, partial cutting provided 115.6 Mg C ha−1 of merchantable timber, while clear-cutting provided 132.4 Mg C ha−1. Strategies aimed at using forest management to mitigate atmospheric C increases need to assess both the direct impacts on the forest ecosystem and the indirect impacts through product and energy substitution associated with the use and storage of harvested biomass. 相似文献
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Jarosław Skłodowski 《Scandinavian Journal of Forest Research》2017,32(2):123-133
I studied ground beetles in clear-cuts that represent six treatments: (i) manual plowing, (ii) plowing with a FAO-FAR FV 4088 cutter, (iii) plowing with an active single-moldboard U-162, (iv) plowing with a double moldboard forest plow LPz, (v) active piling of logging slash and (vi) no plowing or slash piles. The four plowing techniques differed in the depth and extent of their impact. Manual scarification of soil had the least effect on the species diversity, abundance and ecological traits of carabids. The larger the area and the deeper the plowing, the greater was the transformation of carabid assemblages. Piles of branches proved to be beneficial for the preservation of forest species, large species, mesophilic species and those with low dispersal power in clear-cut areas. In general, deep plowing was conducive to an increase in the proportion of individuals representing early succession species, whereas shallow plowing and especially manual scarification favored late succession species. The results suggest that for effective support of carabid beetles in a clear-cut area, only shallow plowing should be used. Piles of branches can be retained in a clear-cut area to provide a shelter supporting for forest fauna. 相似文献
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Markus Hartman Tanja Oksala Hannu Ilvesniemi 《Scandinavian Journal of Forest Research》2019,34(4):282-288
We studied the soil carbon dioxide respiration (Rs) at three clear-cut mesic forest sites in south, central and north central Finland, which had been treated with different intensities of stump lifting and slash removal and then patch mounded and planted with spruce. The follow-up period after the initial calibration lasted for five consecutive years. Throughout the study the Rs remained at fairly steady levels according to the study site and soil disturbance level. Based on a split-plot test using the general linear model there were no significant differences in the Rs between the different stump and slash removal treatments at the three study sites, but unaffected and moderately affected soil surfaces had significantly higher Rs than mounds and wheel ruts. We conclude that the removal of stumps and slash have minor direct effects on Rs, but large indirect effects through soil disturbance. 相似文献
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Sarah C. Davis Amy E. Hessl Carrie J. Scott Mary Beth Adams Richard B. Thomas 《Forest Ecology and Management》2009
Forest succession contributes to the global terrestrial carbon (C) sink, but changes in C sequestration in response to varied harvest intensities have been debated. The forests of the Central Appalachian region have been aggrading over the past 100 years following widespread clear-cutting that occurred in the early 1900s and these forests are now valuable timberlands. This study compared the history of ecosystem C storage in four watersheds that have been harvested at different frequencies and intensities since 1958. We compared NPP, NEP, and component ecosystem C fluxes (g C m−2 year−1) in response to the four different harvest histories (no harvest, clear-cutting, single tree selection cutting, and 43 cm diameter-limit cutting). Clear-cutting had short-term negative effects on NEP but harvest did not significantly impact long-term average annual C sequestration rates. Average plant C (g C m−2) since 1950 was about 33% lower in response to a clear-cut event than plant C in an un-harvested forest, suggesting that the C sequestration associated with clear-cutting practices would decline over time and result in lower C storage than diameter-limit cut, selective cut, or un-harvested forests. Total C stored over a 55-year period was stimulated ∼37% with diameter-limit cutting and selective cutting relative to un-harvested forests. 相似文献
9.
Elevated nitrate concentrations in streams and groundwater are frequently observed following forest harvest. In addition to depleting nutrients available for forest regeneration, elevated nitrate export following harvest can have deleterious effects on downstream aquatic ecosystems. As part of a forest harvest experiment conducted at the Turkey Lakes Watershed, Ontario, Canada, stable isotope techniques were employed to investigate nitrate attenuation in a natural wetland receiving high concentrations of nitrate as a result of clear-cutting in the catchment. Isotopic analysis of nitrate (δ18O, δ15N) and vegetation (δ15N) demonstrated that both denitrification and plant uptake of nitrate resulted in significantly lower nitrate concentrations in wetland outflow compared to incoming stream water. Although the 0.2-ha forested swamp (4% of catchment by area) was too small to be featured on standard topographic maps, the wetland remove 65–100% of surface water nitrate inputs, thereby protecting downstream aquatic habitats from the full effect of N release from forest harvest. The δ15N enrichment factor associated with nitrate attenuation in wetland surface water was lower than typically observed during denitrification in groundwaters, suggesting that nitrate removal is complete in some areas of the wetland. Plant assimilation of nitrate was also partially responsible for the low observed enrichment factor. Wetland plants recorded the high δ15N associated with denitrification activity in portions of the wetland. Apportionment of nitrate sources using δ18O–NO3− at the outlet weir was unaffected by the wetland nitrate attenuation under pre- and post-harvest conditions due to the mid-catchment position of the wetland. Future forest management practices designed to recognize and preserve small wetlands could reduce the potentially detrimental effects of forest harvest on aquatic systems. 相似文献
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杉木人工林采伐迹地造林效果调查分析 总被引：1，自引：0，他引：1
吴远彬 《河南科技大学学报(农学版)》2004,24(2):28-31
对杉木采伐迹地上更新营造的人工纯林及混交林分生长状况进行了调查,结果表明:不同纯林树种和混交林模式的林分生长状况存在明显差异,纯林树种表现为南酸枣>马褂木>杂种马褂木>杉木>桤木>观光木>木荷;混交林模式以杜英+刺楸混交林模式的生长状况最好;在3种杉阔混交林模式中,桤木与杉木混交更有利于杉木的生长,种间关系更为协调。 相似文献
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