林冠截留对杉木人工林生态系统物质循环的影响

根据1999-2002年连续4年的观测数据,对林冠截留在杉木林生态系统物质循环中的作用进行研究.结果表明:每年林冠截留降雨量267.0 mm; 林冠截留蒸发散量占杉木人工林总蒸发散量的27.2%,林冠截留水分的物理蒸发量占杉木林集水区水分输出的18.97%;林内净降水的营养物质为143.329 kg·hm-2a-1,比冠上大气降水输入的63.924 kg·hm-2a-1多74.905 kg·hm-2a-1,增加了117.2%; 林冠截留减少了到达林地表面和入渗土壤的水分,减少了集水区地表水和土壤漏水的输出,从而减少了营养物质的输出,可见,林冠截留是系统保存营养物质的重要机制之一.     

Role of canopy interception on water and nutrient cycling in Chinese fir plantation ecosystem

The role of canopy interception on nutrient cycling in Chinese fir plantation ecosystem was studied on the basis of the position data during four years. Results indicate that the average canopy interception amount was 267.0 mm/year. Canopy interception play a significant role in water cycle and nutrient cycle processes in ecosystem, and was an important part of evaporation from the Chinese fir plantation ecosystem, being up to 27.2%. The evaporation from the canopy interception was an important way of water output from ecosystem, up to 19.9%. The flush-eluviation of branches and leaves caused by canopy interception brought nutrient input of 143.629 kg/(hm² · year), which was 117.2% of the input 63.924 kg/(hm² · year) from the atmospheric precipitation. The decreased amount of 80.1 mm precipitation input caused by canopy interception reduced the amount of rainfall into the stand surface and infiltration into the soil, reduced the output with runoff and drainage, and decreased nutrient loss through output water. Therefore, the additional preserve of nutrient by canopy interception was 8.664 kg/(hm² · year). __________ Translated from Scientia Silvae Sinicae, 2006, 42(12): 1–5 [译自: 林业科学]     

The influence of canopy patch mosaics on understory plant community composition in boreal mixedwood forest

We assessed the composition of understory vascular plant communities in relation to the mosaic of canopy patch types, and their associated structure and environment, within unmanaged, mature boreal mixedwood forests in western Canada. Within a 30 km² area, we sampled patches of four different canopy types: conifer-dominated, broadleaf-dominated, mixed conifer-broadleaf, and canopy gaps (total n = 98). There were significant differences in understory composition among the four patch types (based on multi-response permutation procedure (MRPP)) and these were mainly due to differences in relative abundances of understory species. The understory communities of conifer patches were characterized by low abundances of shade intolerant species while shade-tolerant and evergreen species were indicators (based on an indicator species analysis (ISA)). Understory communities under gap and broadleaf patches were characterized by higher abundances of grasses and shade intolerant species. Gap, broadleaf, and mixed patches had higher abundances of certain shrub species than did conifer patches. The patch types also differed in terms of their environmental conditions. Conifer patches had drier, cooler soils and the lowest understory light. Broadleaf patches had the warmest soils while understory light during the leaf-off period was similar to that of canopy gaps. Gap patches had the lowest litter cover and PO₄⁻ availability and the highest light. Seven environmental variables (soil moisture, soil temperature, total light during the leaf-off period, cover of coarse and fine downed woody material, and availability of NH₄⁺ and Ca²⁺) were significantly related to understory species composition (in a constrained ordination by means of a distance-based redundancy analysis (db-RDA); 16.5% of variation in understory community data explained). Even within a single patch type, there was substantial environmental variation that was related to understory species composition. Our study suggests that the mosaic of canopy patches within mixedwood forests supports coexistence of both early and late successional understory plant species in mixedwood stands. Maintaining the mixture of canopy patch types within mixedwood stands will be important for conserving the natural patterns of understory plant composition in boreal mixedwood forests.     

STUDIES ON FOREST WATER CYCLING

RESEARCHAPPRoACHESAccordingtoresearchscales,weadapttwokindsofresearchmethods.Onthelargcrscale,wedefmethcboundariesofresearchsystCmsaccordingtothewatCrshedsorbasins,andthenresearchontherelationshipbctWeentheinputs(PreCipitation)andoutPuts(streaInflow)andonthermuencesofallkindsofnatUralmpPhiFalfactorsandartfficialdisturban9esreqardingtheintemalsystemsasblackboxes.'onthesmallerscale,accordingtovegetationtyPes,weestablishrunoffplotSandcorrespondinginstallationsinthemainforesttyPeQfvirg…     

森林冠层节肢动物取样研究进展

冠层节肢动物的研究是近来生物多样性研究的国际前沿,文章主要介绍了森林冠层节肢动物的取样方法,如烟雾杀虫剂击倒法、取样树叶和小枝、非引诱式捕获器、诱捕器及其它取样法,并指出了各类取样法的优缺点。     

森林认证对林产品贸易的影响

森林认证在森林经营政策方面扮演了一个重要的补充角色并对林产品贸易起到了极其重要的影响。在短短的10余年间,森林认证已得到许多国家政府和林业部门的关注和认可。森林认证工作在中国刚刚起步,我们应该让更多的人了解森林认证并推动该项工作的发展。本文分析了森林认证对世界林产品贸易的影响,包括认证进出口国的利益、贸易流向、企业竞争、以及人们对认证林产品的需求,论述了森林认证对中国林产品贸易的影响,提出了森林认证对中国森林经营和林产品贸易的影响是机遇与挑战并存。参8。     

长白山北坡阔叶红松林林冠对降雨及其养分的影响

在2001年森林生长季(6-9月),通过测量降雨各分量,分析了中国吉林省长白山北坡红松阔叶林冠层对降水分配各分量的影响。结果表明:干流量(37.39 mm),透流量(326.02 mm)和截留量(105.67 mm),分别占同期降雨量(469.08 mm) 的7.97%、69.50%和22.53%。林冠对降雨的月份分配规律是:树干茎流率的月变化为七、八月份大于其它月份,穿透率从6-9月份有逐渐减少的趋势,而截留率的变化正好与穿透率相反,从19.43%增加到31.02%。林内降雨中的养分元素浓度发生显著变化,除Ca、Mg外,其它元素的浓度都有所增加。经分析得出,大气降雨中养分元素的浓度序列为:Ca> Mg> N> K> Fe > P> Cu > Mn;而穿透雨中养分元素的浓度序列为:K>N>Mg>Ca>P>Fe>Mn>Cu;在林冠淋溶中各养分元素的浓度序列为:Mn> P>K>Cu>Fe>N>Mg>Ca。图1表5参13。     

The influence of experimental acidification on nutrient release and decomposition rates of needle and root litter in the forest floor

The influence of experimental acidification (diluted H₂SO₄) on mass-loss rates of needle and root litters was investigated in forests of Scots pine, lodgepole pine, Norway spruce and white birch located in a climatic transect through Sweden. Of the two dosages given (32 and 96 kg S ha⁻¹), significant effects on mass-loss rates were observed mainly with the higher dose. When comparing the effect of acid on mass-loss rate of needle litter on all sites together for the whole 3-year period, no effect was seen. By distinguishing the different types of forest and understorey we found a significant general decrease in rate for needle litter of about 8% for the pine forest sites (n = 10). For the spruce sites (n = 8) and the birch sites (n = 2) no significant effects were seen. When considering single sites after 1 year of decomposition, significant effects (rate decrease) were also found for the birch forests. At some spruce sites significant differences in mass-loss rate were seen (both rate increase and rate decrease). When a significant effect was seen its magnitude was found to be dependent on the decomposition rate (soil biological activity) of that site.For root litter the results were less clear. No significance was seen when comparing all sites together or sites of one type of forest. Significant decreases in mass-loss rate after acid treatment were, however, noted for some of the sites after different incubation periods. The patterns of dynamics of the nutrients N, P, S, K and Ca were not affected whereas those of Mg and Mn were and significantly higher release rates were found for these nutrients after acid treatment. The release rates of the nutrients N, P, S, K and Ca from litter were proportional to litter mass-loss and for the Scots pine stands this meant a decreased release rate for these nutrients.     

Dry matter production and nutrient cycling in agroforestry systems of cardamom grown underAlnus and natural forest

A study on dry matter production and nutrient cycling in agroforestry systems of cardamom grown under N₂-fixingAlnus and mixed tree species (non-N₂-fixing) was carried out in the Sikkim Himalaya. The stand total biomass, and tiller number, basal area and biomass of cardamom crop was much higher under the influence ofAlnus. Annual net primary productivity ofAlnus trees was slightly higher than mixed tree species in spite of lower stand density ofAlnus. The agronomic yield of cardamom increased by 2.2 times under the canopy ofAlnus. Litter production and its disappearance rates were also higher in theAlnus-cardamom stand. Nitrogen and phosphorus concentrations of different components ofAlnus were higher than those of mixed tree species, whereas their back translocation from leaf before abscission was lower inAlnus. The cardamom based agroforestry system under the influence ofAlnus was more productive with faster rates of nutrient cycling. The poor nutrient conservation and low nutrient use efficiency ofAlnus, and malleability of nutrient cycling under its influence make it an excellent association which promotes higher availability and faster cycling of nutrients.     

森林生态系统养分循环的研究

森林具有多功能、多效益的特点,人们对森林经营的要求,不仅是经济效益,随着社会的发展更日益着重于生态效益和社会效益.因此对森林生态系统定位研究的成果,将会为森林经营管理者提供决策的理论基础和最佳的实施方案.如若对系统中各成分和功能过程得到全面的了解,通过系统的计算机模拟可以表示出系统内各成分相互作用以及整个系统对不同干扰、环境污染和经营管理措施的反应,将对实现林业向生态化转变,为森林多效益稳定而永久利用发挥作用.     

The influence of stoniness and canopy properties on soil water content distribution: simulation of water movement in forest stony soil

Mountainous forest soils usually contain a large number of rock fragments (particle diameter >2?mm), which influence soil properties. Data characterizing hydraulic properties of these soils usually describe only the fine soil fraction (particle diameter <2?mm) properties. To quantitatively describe soil water movement in stony soils, it is necessary to evaluate effective hydrophysical characteristics, involving the influence of stones, that is, the effective hydraulic conductivity and retention capacity should be known. Properties of evaporating surface (plant canopy) also play important role in formation of soil water movement and retention. This work presents results of the study of rock fragments (stoniness) effect on soil water content profiles and soil water dynamics during the season. Stony and homogeneous soil behavior is compared. The effect of different canopies (spruce forest, low vegetation) and bare soil in both types of soils on soil water dynamics is also studied. Stones as a part of soil are decreasing its water capacity and hydraulic conductivity as well. This is expressing in the decrease of stony soil water content retention capacity. High interception capacity of trees, followed by the low undercanopy precipitation, leads to the decreased soil water content of the upper soil layer. Combination of stony soil and dense forest canopy led to the low undercanopy precipitation, to relatively low infiltration totals into soil, and to decreased outflow.     

Effects of an exotic conifer (Pinus radiata) plantation on forest nutrient cycling in southeastern Australia

The distribution and movement of N, P, K, Na, Mg, and Ca were studied in southeastern Australia in a 37—year-old Pinus radiata plantation and in a nearby Eucalyptus obliqua — Eucalyptus dives forest of the same age and of the same type as that which had been replaced by the P. radiata plantation. The soil beneath the P. radiata plantation contained significantly less total N and exchangeable K, Mg, and Ca than that beneath the eucalypt forest. No large accumulation of nutrients was found in either the litter or the trees in the P. radiata plantation relative to that in the eucalypt forest. However, there was a slightly greater accumulation of N and K in the P. radiata biomass than in the eucalypt biomass. The annual soil nutrient balance obtained by subtracting outputs (mineral soil leachate + biomass incorporation) from inputs (precipitation + mineral weathering) indicated a more favourable balance for each nutrient in the soil beneath the eucalypts than in the soil beneath the pines. Calculations suggested that these balances could only partially account for the differences in soil nutrient quantities between eucalypt and pine ecosystems. It was hypothesized that these differences are also partially explainable in terms of the nutrient losses accompanying two fires which had occurred in the pine plantation area. Nitrogen balances in this study were incomplete because several potentially important fluxes were not measured.     

洞庭湖区防浪林林分林冠结构的研究

对洞庭湖区河洲、滩地上的不同林龄的旱柳、杨树防浪林、芦苇林进行了标准地调查,选取标准株(地),对其茎杆、枝条、叶片的空间分布进行了测定,通过对其差异进行比较分析,旨在间接测定不同防浪林的防浪效益的差异。     

A review of the roles of forest canopy gaps

Treefall gap, canopy opening caused by the death of one or more trees, is the dominant form of disturbance in many forest systems worldwide. Gaps play an important role in forest ecology helping to pre- serve bio- and pedo-diversity, influencing nutrient cycles, and maintain- ing the complex structure of the late-successional forests. Over the last 30 years, numerous reviews have been written describing gap dynamics. Here we synthesize current understanding on gap dynamics relating to tree regeneration with particular emphasis on gap characteristics consid- ered critical to develop ecologically sustainable forest management sys- tems and to conserve native biodiversity. Specifically, we addressed the question： how do gaps influence forest structure？ From the literature re- viewed, the size of gaps induces important changes in factors such as light intensity, soil humidity and soil biological properties that influence tree species regeneration and differ in gaps of different sizes. Shade- tolerant species can colonize small gaps; shade-intolerant species need large gaps for successful regeneration. Additionally, gap dynamics differ between temperate, boreal, and tropical forests, showing the importance of climate differences in driving forest regeneration. This review summa- rizes information of use to forest managers who design cutting regimes that mimic natural disturbances and who must consider forest structure, forest climate, and the role of natural disturbance in their designs.     

森林经营活动对生态环境的影响

森林经营对生态环境产生的影响,特别是对水土流失、涵养水源方面的影响是人们关注的焦点之一。章对于我国森林经营活动对生态环境产生的影响进行了总结,主要包括对森林的保持水土,涵养水源功能及生物多样性等方面的影响,并指出今后森林经营中应注意的一些问题。     

防护林体系对噪声的影响

利用人工设置的噪声 ,在空旷、林带、片林进行了噪声强度测定 ,研究出噪声强度在空旷地、不同结构的林带、不同树种组成的林分中的变化情况 ,提出了防止环境噪声应采取的措施。     

林冠截水作用研究

通过对毛竹林、杉木南酸枣木荷混交林、杉木林、柑桔林四种林分的林冠截留降水作用研究，分析了各林分林冠层及其纵向、横向截水作用规律。     

THE CHARACTERISTICS OF THE NUTRIENT CYCLING IN BIRCH STANDS WITH DIFFERENT AGE STAGES

SuccessionisthedynanucdeveloPInentofecosystemswhichcanbecharactetindbyenergyandndneralcyclings.Eachsuccessionstagehasitscharaceristicsofelementcycling.SomeschOlarshaveStatedbutbrieflawsofnutrienCyclinginsuccessionstagesI"3I.InthespaPer,thenutrientcyclingcharacterishcsofbirchsuccessionseriesinXiaokinganlingwerediscussed.SwrYAasAroarernoDSThestUdyareaislocatedinLiangshniNatUralReservesinthendddieofXiaox-ing'anlilg(l28"53,2o'rE,47olo'5O"N).Theclimat6belongstocontinentalmonsoonclimate,W…     

The influence of some forest operations on the sustainable management of forest soils-- a review

This review paper describes the nature and scale of changesto forest soils brought about by forestry operations. A relativelynon-technical approach is adopted with the aim of stimulatingdebate within as wide an audience as possible. The paper doesnot aim to be exhaustive but rather a position statement. Areaswhere further study is required are highlighted. The concept of sustainability is explored in relation to forestsoils, and the condition highlighted is that impacts of forestmanagement operations should not, in the long term, exceed thecapacity of soil to recover by natural processes (e.g. erosionlosses should not exceed soil formation rates, nutrient removalsshould not exceed nutrient inputs etc.). Soil erosion, nutrientremoval, compaction, and changes in organic matter content andsoil water status are identified as the most important processesinvolved in the impacts of management. The impacts of some of the more intensive forest managementregimes on soil compaction, nutrient removal and erosion ratesappear to be of similar magnitude to the recovery capacity ofsoils. Where the most intensive forms of forest operation areused on susceptible sites some degree of long-term soil degradationappears to be likely, and it can be regarded as valid to describesuch management practices as unsustainable. However, the scaleof occurrence of such management is probably relatively modest,and decreasing. On less susceptible sites, and where less intensiveforms of management are employed, impacts on soils are low enoughfor management to be regarded as sustainable, and are oftenless than under pre-existing land uses. Compaction caused byheavy harvesting and extraction machinery, nutrient depletionresulting from whole tree harvesting on infertile sites whererotations are short, and erosion following cultivation and harvestingon erodible soils are the greatest causes of concern. Compliancewith recent Forestry Commission guidelines should lead to lowerimpacts than those recorded during recent decades. However,rotation-length audits of the impacts of different forest managementregimes on a range of site types are needed before definitivestatements about the sustainability of management operationscan be made.     

刺五加林冠下栽培技术

本文从林地选择、硬枝扦插育苗、移栽和田间管理、采收四个方面介绍了刺五加林冠下栽培技术.