森林采伐对森林生态因子的影响

本文系统地介绍了森林采伐后，各项生态因子的变化情况，通过皆伐区，择伐区、对照区各项同生态因子的比较，认为森林采伐对森林生态因子有明显的影响，对生态环境具有破坏作用森林皆伐后，林地光照、地表月平均最高气温、月平均蒸发量都显著高于对照区，森林采伐后失去了保水、保土的作用，使森地土壤及氮、磷、钾、有机质等养分大量流失；森林采伐后下草、下土也发生明显的变化，喜光植物代替耐荫植物侵入并成为优势种，给人工更新的和幼林抚育带来困难，择伐方式比皆伐方式破坏环境轻。     

试论秦巴山区森林采伐与更新方式问题

1 森林经营利用的原则森林采伐与更新是两种本质上不同的概念,而又是统一的事物。有什么样的采伐方式就有相应的更新方式。森林采伐方式因自然环境,林分结构,经营目的,经济条件与技术条件而不同。因之不能笼统地说某种采伐方式好与坏。森工采育企业在文革期间,大量采用皆伐,开展万方连运动,结果造成普遍的生态灾难。如太白林业局的苏家沟林场28林班,1979、1980两年大面积皆伐,1980年秋即发洪灾,在1981年连续强度降雨下,造     

白龙江林区森林采伐与更新方式的探讨

白龙江林区属于冷云杉成过熟林占优势的单层原始林区,经验证:宜采用小面积块状皆伐的采伐方式,伐后人工植苗更新,同时论述了该采伐方式与水土流失的关系,并强调了按林业部颁《森林采伐更新管理办法》等有关规定,伐后及时人工更新恢复植被是不会引起水土流失的。     

采伐方式对马尾松林下植被和土壤肥力的影响

采伐作业是森林经营中重要环节,不同采伐方式对森林植被和土壤肥力产生不同的影响。文章对32年生马尾松林开展不同采伐方式试验研究,结果表明,随着采伐强度增大,林下植被得到恢复和发展,但皆伐方式导致植被严重破坏;土壤孔隙度、持水量等物理性质及全氮、水解氮、速效磷、速效钾等化学性质均随采伐强度增大不断下降,土壤容重增加;皆伐使土壤理化性质恶化。     

采伐方式对马尾松林下植被和土壤肥力的影响

采伐作业是森林经营中重要环节,不同采伐方式对森林植被和土壤肥力产生影响。通过对32年生马尾松林开展不同采伐方式试验研究,结果表明:随着采伐强度增大,林下植被得到恢复和发展,但皆伐方式导致植被严重破坏;土壤孔隙度、持水量等物理性质及全氮、水解氮、速效磷、速效钾等化学性质均随采伐强度增大而不断下降,土壤容重增加,皆伐使土壤理化性质恶化。     

加速湾沟林业局森林经营培育进程的初步探讨

本文对湾沟林业局转变森林采伐方式，减少皆伐伐区作业量，加大择伐作业量，推算出了皆伐与择伐经营周期，要比全部实行皆伐经营周期提前八年达到周而复始地轮伐生产周期，提供低价林改造对象作法，为森林经营培育，木材生产管理及低价林改造提供理论依据。     

采伐森林和林木的特殊规定

《森林法》第三十一条规定,采伐森林和林木必须遵守下列规定：（1）成熟的用材林应当根据不同情况,分别采取择伐、皆伐和渐伐方式,皆伐应当严格控制,并在采伐的当年或者次年内完成更新造林（2）防护林和特种用途林中的国防林、母树林、环境保护林、风景林,只准进行抚育和更新性质的采伐;（3）特种用途林中的名胜古迹和革命纪念地的林木、自然保护区的森林,严禁采伐。     

东方红林区的森林采伐与更新

1978年,我们曾对东方红林区进行为期一月的考察。考察的主要内容是森林采伐与更新。考察的方法以现场观察为主,并利用典型抽样的方法,做了部分样地和解析木。现将考察结果简报如下。一、关于森林采伐通过对皆伐和择伐迹地的考察,我们得出两点看法。一是靠天然更新的皆伐方式是失败     

内蒙古大兴安岭林区森林采伐更新方式的探讨

内蒙古大兴安岭林区经过 5 0a来的开发 ,目前采用的几种森林采伐更新方式已不能完全适应新形势的要求 ,应对其进行必要的改革。文章从林区实际情况出发 ,对森林采伐更新方式进行了详细的分析探讨 ,指出小面积皆伐和一次性采育伐是较适合的方式     

长白落叶松人工林更新迹地上松毛虫发生情况的调查

通过调查发现,松毛虫对落叶松人工林采伐迹地上更新的红松、落叶松、樟子松的危害与采伐时间、采伐方式,伐前虫口密度、伐前防治有关。8—9月份采伐,虫口密度为0—0.2条/m~2,比10—12月份采伐的虫口密度(1.0—2.7条/m~2)低;块状皆伐的虫口密度为1.2条/m~2较带状皆伐虫口密度(0.1条/m~2)高。     

Effects of harvesting on soil properties and regeneration quality in larch-birch forest in China

INTRoDUCTIONoneopeationsite,locatCdin5O'47'Nandl24"2o'E,wasselectCdastCstsite,Wherethelarch(Larixgmelinii)dominatesmostlythetreepopulahonwithnearlyeightypercentin.standingvolume.Theresttreesarebirch.Annalprecipitation,tethperAnandvaPori-zationare5lonun,-2.4Cand3lommrespec-tively.Elevationisaround45Omoversealevel.CuttingmethodsusedinthissitewereselechvecuningandclearcuttingwithgrQUndtractorskiddingaswellasasmallpwtofani-malskidding.CHANGESoFSoILPRoPERTIESCAUSEDBYHARVESTI…     

The effect of logging on vegetation composition in Western Massachusetts

Forest harvesting is one of the most significant disturbances affecting forest plant composition and structure in eastern North American forests, yet few studies have quantified the landscape-scale effects of widespread, low-intensity harvests by non-industrial private forest owners. Using spatially explicit data on all harvests over the last 20 years, we sampled the vegetation at 126 sites throughout central and western Massachusetts, one-third of which had not been harvested, and two-thirds of which had been harvested once since 1984. Seedling and sapling densities increased with increasing harvest intensity, but decreased to levels similar to unharvested sites by year 20 for all but the most intensive harvests. The composition of understory trees appears to be only slightly changed by harvesting, and was strongly correlated with adult tree composition. Regeneration was dominated by Betula lenta followed by Pinus strobus; Quercus spp. exhibited little sapling recruitment, even in Quercus-dominated stands. Total vascular plant species richness increased substantially with harvesting on low C:N sites (i.e., rich soils), but was only slightly increased on high C:N sites. While harvesting was associated with a statistically significant change in vascular plant composition, non-metric multidimensional scaling revealed that climate (temperature, precipitation) and C:N ratios were the major correlates of composition. Overall, the compositional impacts of harvesting were minor, perhaps because of the low-intensity of harvesting. However, our results support observations from elsewhere in the northeastern U.S. of limited oak regeneration on both harvested and unharvested sites. In addition, our results suggest that increased harvest intensity may be expected to alter forest composition, particularly on rich sites where invasive species may increase as a result of harvesting.     

森林采伐对迹地径流流量的影响

本文利用实验方法,对针阔混交林地实施不同方式森林采伐作业后,迹地和径流量发生的变化进行了样地实验研究。结果表明,皆伐对迹地径流量变化影响程度最大。     

Post-fire natural regeneration of young stands on clearcut and partial-cut and uncut sites of boreal mixedwoods

Boreal mixedwoods are an important element and the most productive forest type in the Canadian boreal forests. However, they experience frequent disturbances. In order to better understand the responses of boreal mixedwoods to different combinations of anthropogenic and natural disturbances, we investigated the natural regeneration of boreal mixedwoods that were previously subjected to three different harvesting treatments (clearcut, partial-cut and uncut control) and naturally regenerated, but subsequently burnt by a severe natural fire 6 years later. The study was conducted 8 years following the fire. Significant interactions were found among harvesting method, species and block in several regeneration variables. There were a total of 12 woody species (trees and shrubs) regenerated, but not all the species were present in all the sites. In general, the species richness and species diversity of the new stands were lowest on clearcut sites while the differences between partial-cut and control varied with blocks. However, the combined total density for all species was lowest on uncut control sites. Density and regeneration index data show that trembling aspen was the predominant tree species in all stands except at one uncut control site where jack pine was the dominant species. The density of trembling aspen generally declined from clearcut to partial to the uncut control. Pincherry, beaked hazel and mountain maple were the dominant shrub species in the new stands, but no general patterns were found in terms of variations in density with harvesting methods for any of the shrub species. Jack pine and white birch were the tallest tree species in the clearcut treatment while white birch was taller than jack pine in the partial-cut and control. The results suggest that active measures are necessary to restore the complex structure of the initial mixedwoods.     

Spatial impacts of soil disturbance and residual overstory on density and growth of regenerating aspen

We examined spatial aspects of harvesting impacts on aspen regeneration at 25 sites in northern Minnesota. These sites had been clearcut or partially harvested 4–11 years ago. At each site, residual overstory, which was composed of trees other than aspen, soil disturbance, and tree regeneration were determined along transects leading away from skid trails into the neighboring stand. We characterized spatial extent of soil disturbance as soil strength using an Eijkelkamp soil cone penetrometer. Soil disturbance dropped off very quickly at the edge of skid trails, suggesting that the impact of harvesting traffic on areas adjacent to skid trails is minor. On skid trails, disturbance levels were higher on sites harvested in summer than on sites harvested in winter. Even after adjustment for differences in soil disturbance, stands harvested in winter had higher regeneration densities and greater aspen height growth than stands harvested in summer, suggesting that aspen regeneration was more sensitive to a given level of soil disturbance on summer-harvested sites versus on winter-harvested sites. Soil disturbance and residual overstory interactively reduced aspen regeneration densities and height growth, indicating that avoidance of soil disturbance is even more critical in partially harvested stands. Predictions based in the spatial patterns of impact found in this study indicated that harvesting conditions may have a great impact in future productivity of a site.     

关于皆伐的思考

本文从景观层次上对皆伐的应用进行了分析 ,得出皆伐是森林主伐的一种行之有效的方式。在森林主伐中 ,应根据立地条件和景观格局 ,恰当考虑皆伐的应用。     

Effects of harvesting intensities and techniques on re-growth dynamics and quality of Terminalia bellerica fruits in central India

Terminalia bellerica Roxb.(Belleric myrobalan)is one of the important multipurpose trees in central India.The fruits of the tree are highly valued for medicinal uses,with the greatest demand coming from the pharmaceutical industry.This has resulted in overexploitation and present harvesting practices have led to a significant decline in natural regeneration for this tree species.Our study was conducted from 2006 to2009 in Chhattisgarh(India)to standardize suitable harvesting practices for sustainable management for this valuable species.Experiments were conducted at four different sites located in Dhamtari,Sarguja,and Raigarh forest divisions of the state,covering both protected and open forest in a complete randomized block design(RCBD).At each site,linear transects of 200 m別100 m(2 ha)were randomly selected to sample the initial population and study the effects of two harvesting methods(traditional and nondestructive)and four harvesting intensities(60%,70%,80%,and 90%)on the sustainability of T.bellerica.Fruits were collected and analyzed for their tannin and gallic acid content.Significant increase in tannin and gallic acid content was found with the maturity of fruits(September to December).This is the first study to experimentally assess the consequences of harvesting of T.bellerica fruits in central India.Our findings reveal that harvesting intensity,time,and method are key factors for maintaining the population.Nondestructive harvesting methods were found to be superior to traditional harvesting in terms of regeneration,recruitment,and concentration of active ingredients.When the fruits were harvested through non-destructive means at maturity,the population of species increased.The study concludes that 70%harvest of T.bellerica fruits through non-destructive means maintains the sustainability and provides quality raw material for the pharmaceutical industry.     

森林采伐迹地清理方式对迹地土壤理化性质的影响

采伐剩余物迹地清理是森林作业的重要组成部分之一。本文通过在黑龙江省带岭林业局野外迹地取样和实验室分析 ,对森林采伐剩余物迹地清理方式对迹地土壤的影响进行了初步研究。结果表明 ,迹地清理方式对作业迹地土壤理化特性产生一定程度的影响 ,进而影响森林采伐后的迹地天然更新与苗木生长质量。研究结果还表明 ,火烧和堆积方法对迹地土壤物理特性影响不十分显著 ,但对土壤的化学特性影响十分显著 ,尤其是火烧迹地土壤养分流失程度差异比较显著     

Changes of key soil parameters five years after forest harvesting suggest slow regeneration of disturbed soil

Forest soil is susceptible to changes in its top layers. These changes occur during ground-based forest harvesting and the rate of soil regeneration depends on the environmental conditions and the extent of the disturbance. This paper was focused on analyzing the changes of soil characteristics such as the depth of the erosion profile, bulk density of soil, its penetration resistance, and the subsurface concentration of CO₂ in soils five years after forest harvesting. The study took place in four forest stands harvested by a skidder and a harvester/forwarder combination. Statistical analyses did not prove significant changes of the characteristics of the disturbed soil after the five-year period without machine traffic: the profile depth did not change significantly, except for one stand, where the ruts became deeper. Other characteristics, such as the bulk density of soil also did not show any significant regeneration (1.29–1.36 g cm^?3 in the rut; initial measurements versus 1.34–1.38 g cm^?3 in the rut; repeated measurements). The penetration resistance, as well as the subsurface CO₂ concentration, were variable, and the results inconclusive. Our results suggest that five years was not enough time for soil to regenerate significantly after being disturbed by ground-based machinery.     

森林采伐作业对迹地径流水质的影响

在综合国内外有关研究成果基础上,本文对森林采伐作业对迹地径流水质的影响进行了研究,结果表明,采伐强度越大,对水质影响越显著。