伞伐更新法对赫卡尼亚(Hyrcanian)森林系统中森林再生和林分结构的影响

研究伞伐更新法对赫卡尼亚森林系统中森林再生和林分结构的影响。在伊朗北部优势种为山毛榉（Fagus orientalisLipsky）的硬木林,采取伞伐更新法和非伞伐更新法方法设计实验区。结果表明,在山毛榉（F orientalis Lipsky）林中采用伞伐更新法处理,明显影响林下草本植物种的频度和密度。伞伐更新法处理后,林堇菜（Viola silvestris Lam.）、车叶草（Asperula odorata L.）、苔草（Carex spp.）和悬钩子（Rubushyrcanus Juz）的种频度明显增加。在对照区,树种的胸高直径（57.50±2.15cm）大于被处理区（50.67±1.88cm）的树种的胸高直径（50.67±1.88 cm）,但对照区和处理区的树种的高度值相似。在1995-2005年间,波斯铁木（Parrotia persica）苗木数量增加到13.2%,而山毛榉（F orientalis）和欧洲鹅耳枥（Carpinus betulus）的苗木数量却明显减少。总之,应该利用其它育林方法,如,带状择伐作业,而不是伞伐更新法培育赫卡尼亚森林中山毛榉林。     

Exploring adaptation to climate change in the forests of central Nova Scotia, Canada

The threat of climate change is now recognized as an imminent issue at the forefront of the forest sector. Incorporating adaptation to climate change into forest management will be vital in the continual and sustainable provision of forest ecosystem services. The objective of this study is to investigate climate change adaptation in forest management using the landscape disturbance model LANDIS-II. The study area was comprised of 14,000 ha of forested watersheds in central Nova Scotia, Canada, managed by Halifax Water, the municipal water utility. Simulated climate change adaptation was directed towards three components of timber harvesting: the canopy-opening size of harvests, the age of harvested trees within a stand, and the species composition of harvested trees within a stand. These three adaptation treatments were simulated singly and in combination with each other in the modeling experiment. The timber supply was found to benefit from climate change in the absence of any adaptation treatment, though there was a loss of target tree species and old growth forest. In the age treatment, all trees in a harvested stand at or below the age of sexual maturity were exempt from harvesting. This was done to promote more-rapid succession to climax forest communities typical of the study area. It was the most effective in maintaining the timber supply, but least effective in promoting resistance to climate change at the prescribed harvest intensity. In the composition treatment, individual tree species were selected for harvest based on their response to climate change in previous research and on management values at Halifax Water to progressively facilitate forest transition under the altered climate. This proved the most effective treatment for maximizing forest age and old-growth area and for promoting stands composed of climatically suited target species. The size treatment was aimed towards building stand complexity and resilience to climate change, and was the most influential treatment on the response of timber supply, forest age, and forest composition to timber harvest when it was combined with other treatments. The combination of all three adaptation treatments yielded an adequate representation of target species and old forest without overly diminishing the timber supply, and was therefore the most effective in minimizing the trade-offs between management values and objectives. These findings support a diverse and multi-faceted approach to climate change adaptation.     

A conceptual model to characterize disturbance severity in forest harvests

I present a three-dimensional disturbance severity model and illustrate the potential usefulness of the model for characterizing disturbance conditions caused by forest harvesting. Disturbance is most often described in terms of disturbance type, size and frequency, with less emphasis on severity. In addition, studies of disturbance impacts have emphasized the dominant tree and woody understory layers, overlooking the species-rich herbaceous layer. For a wide range of harvesting treatments (clearcutting to selection systems with and without site preparation), I characterized disturbance severity based on hypothesized patterns of canopy removal, understory vegetation removal and forest floor and soil modification. To illustrate the application of the model, I plotted the data from three studies in North American coniferous and mixed coniferous–deciduous forests in the three-dimensional diagram of disturbance severity, using actual measures of the degree of disturbance on each axis or estimates inferred from other related variables. The plotted points showed general agreement with the hypothesized ranges of disturbance severity for the treatments represented in these studies. The three axes of disturbance severity can be affected differently depending on disturbance type, emphasizing the importance of characterizing the degree of disturbance on each of these three axes. Short-term responses of the herbaceous layer are strongly influenced by disturbance severity on each of these three axes. Disturbance conditions must be quantified before vegetation indicators of these conditions can be identified. The conceptual model provides a framework for comparing forest harvesting treatments to natural disturbance events. These comparisons are critical to designing ecologically sustainable forest management strategies.     

Forest structure, composition, and tree diversity response to a gradient of regeneration harvests in the mid-Cumberland Plateau escarpment region, USA

Upland hardwood stands on mesic, escarpment-oriented sites on the Cumberland Plateau region of northeastern Alabama provide a myriad management opportunities. Stands are primarily managed for Quercus, but the high species diversity allows for management that targets multiple species. Stand composition is unique in that dominant species include shade tolerant species such as Acer saccharum, intermediate tolerant Quercus spp. and Carya spp., and intolerant Liriodendron tulipifera. Three replications of five levels of disturbance were created to assess species compositional changes; disturbances included three levels of harvest intensity, a mid-story herbicide treatment, and a control. After eight growing seasons, there were no discernable differences in species richness, diversity or evenness. Importance values based on relative basal area and relative density also changed little, except for clearcuts where L. tulipifera greatly increased. An initial gradient in basal area, canopy cover, and light created by harvesting or thinning dissipated following five growing seasons. Options exist for future stand management, including promoting two-aged or uneven-aged systems. Maintenance of Quercus will require additional tending.     

Response of terrestrial small mammals to varying amounts and patterns of green-tree retention in Pacific Northwest forests

To sustain native species in managed forests, landowners need silvicultural strategies that retain habitat elements often eliminated during traditional harvests such as clearcut logging. One alternative is green-tree or variable retention. We investigated the response of terrestrial small mammals to experimental harvests that retained large live trees in varying amounts (approximately 100, 75, 40, and 15% of original basal area) and patterns (aggregated versus dispersed) in mature coniferous forests of western Oregon and Washington. Treatments were applied in 36, 13-ha experimental units. We used pitfall traps to sample small mammals for 4 weeks each autumn during 2 years before and 2 years after treatments. We captured 21,351 individuals of 32 species. We analyzed effects of treatments on relative abundance of 12 species. As level of retention declined, we expected species associated with closed-canopy forests to decrease (Sorex trowbridgii, Neurotrichus gibbsii, Peromyscus keeni, Myodes [Clethrionomys] californicus, and M. gapperi); species associated with early successional habitats to increase (S. vagrans, P. maniculatus, Microtus longicaudus, and Microtus oregoni); and habitat generalists to show little response (S. monticolus, S. pacificus, and S. sonomae). As expected, M. californicus declined after harvest, and P. maniculatus and M. longicaudus increased. Sorex sonomae showed an unpredicted decrease. Other species did not show consistent changes. Responses of S. monticolus, S. sonomae, and M. gapperi varied among study areas. For M. gapperi, this variation was not explained by differences in habitat structure among areas. For all species, capture rates were similar in dispersed- and aggregated-retention units. Similarity in species composition between harvested sites and controls decreased with decreasing retention. Future sampling of these treatments is needed to assess long-term responses. Based on our initial results, green-tree retention strategies need to be sensitive to regional variation in environmental characteristics and small mammal community composition.     

试论林产品结构与展望

本文针对黑龙江省森工系统林产品的生产现状进行了分析和评述,依据我国的改革开放政策,结合黑龙江森工系统的实际情况和国内外林产品的发展趋势,作者提出自己的观点。     

Ten-year response of bird communities to an operational herbicide-shelterwood treatment in a northern hardwood forest

Use of herbicides in forestry to direct successional trajectories has raised concerns over possible direct or indirect effects on non-target organisms. We studied the response of forest birds to an operational application of glyphosate and sulfometuron methyl herbicides, using a randomized block design in which half of each 8 ha block received herbicide and the other acted as a control, on shelterwood seed-cut Allegheny hardwood stands in northwestern Pennsylvania. We monitored birds using 50 m radius point counts in two pretreatment years and for 10 years post-treatment (1992-2004). Fences were erected six years after herbicide treatment in response to increased deer browsing at a subset of sites. Avian responses to herbicide treatment varied by nesting guild: we detected no response by cavity-nesters, but documented declines in the shrub-, ground- and canopy-nesting guilds. Responses were short-lived (2-4 years post-treatment), but shrub-nesters did not recover until fencing provided regenerating vegetation respite from browsing. Thus, apparent responses of birds to herbicide were confounded with deer browsing in this study. High species turnover, even within control plots, suggests that avian communities may be assessed more appropriately assessed at larger spatial scales than those used in this study (6.5-8 ha).     

Biodiversity response to intensive biomass production from forest thinning in North American forests - A meta-analysis

Demand for alternative energy sources has led to increased interest in intensive biomass production. When applied across a broad spatial extent, intensive biomass production in forests, which support a large proportion of biodiversity, may alter species composition, nutrient cycling and subsequently biodiversity. Because forest thinning and fuels treatment thinning are viewed as possible wide-spread biomass harvest options, it is important to understand what is known about forest biodiversity response to these practices and what additional information is needed by forest managers and policymakers. Therefore, we summarized documented relationships between forest thinning treatments and forest biodiversity from 505 biodiversity effect sizes (incl. taxa and guild abundance and species richness measures) from 33 studies conducted across North America. We used meta-analysis to summarize biodiversity response by region, taxa and harvest treatments. Biodiversity responses included species richness, diversity, abundance of taxa or groups of species (guilds) and abundance of individual species for birds, mammals, reptiles, amphibians, and invertebrates. Forest thinning treatments had generally positive or neutral effects on diversity and abundance across all taxa, although thinning intensity and the type of thinning conducted may at least partially drive the magnitude of response. Our review highlights the need for more research to determine effects of thinning on amphibians and reptiles and manipulative experiments designed to test the effects of biomass removal on biodiversity.     

An ecological approach to forest harvesting

This paper deals with the relationships between forest harvesting and forest ecology. It proposes basing annual cuts and forest operation plans on ecological principles. Harvestablc forest resources arc decreasing and regeneration is slow. The combination of forest harvesting with ecology can be viewed as a solution to the forest harvesting dilemma in China.This paper also makes some technical recommendations for forest operations based on ecological principles.     

The response of ground vegetation to structural change during forest conversion in the southern Black Forest

The aim of this study is to investigate the effects of forest conversion on forest floor vegetation. ‘Ecological’ forest conversion, as defined by an interdisciplinary southern Black Forest project group, describes the transformation of even-aged spruce (Picea abies L. H. Karst.) stands to structured continuous cover forests consisting of spruce (Picea abies), silver fir (Abies alba Mill.) and beech (Fagus sylvatica L.). In order to analyse the conversion process, four conversion stages were defined in a conceptual forest development model. Four forest districts deemed to be representative of the southern Black Forest region were selected for the study. The ground vegetation was initially classified independently from the stand structures. Subsequently, the relationship between stand structures, as determined by development stage, and ground vegetation was analysed. It was revealed that forest conversion modified the ground vegetation. The main factors influencing ground vegetation were the influence of broadleaves, predominately beech (F. sylvatica), on the canopy composition and litter coverage on the one hand; and the canopy coverage of spruce, the proportion of needle litter and the associated light penetration on the other. The prevalence of moss and vascular plant species preferring acidic sites found in spruce forests decreased during the transition process, whereas, species requiring a moderate base supply increased in abundance. The continuous cover forest representing the final stage of conversion increasingly contained a mixture of ground vegetation species normally associated exclusively with either conifer or deciduous forest. Due to the fact that there is an associated ground vegetation specific to the different stages of forest conversion in stands dominated by Norway spruce or European beech and a mixture in the latest conversion stages, large-scale forest conversion should be avoided in favour of management promoting a diversity of silvicultural goals and treatments in neighbouring stands. Only a variety of treatments ensures the maintenance of floristic diversity in the long-term.     

Ideal Point Method Applied in Forest Harvest Regulation

IDttoductionl'I'lSuPposingthereare111objechvef(x).f(x),...Jm(x),eachobjechvehasifsoph111alsoluhonorophmalvaluefIfforl,2,--.,m,oneofanyvaluesistakenin111se-ries,.(i)willbesame,itisx',thenx=x',everyobjechvemcyreachitsOPtimalPOint.Infact,itisverydifficulttor…     

对双鸭山林区森林分类经营的认识

本文对双鸭山林区森林的分类经营提出了几点认识,并做了具体分析。     

河北省国有林场森林采伐管理问题及对策研究

采用参与式调查法,对河北省几个典型国有林场的森林采伐管理存在的问题进行实地调研。通过对调查结果的分析发现,河北省国有林场森林采伐存在限额不足,采伐类型过多,采伐审批手续复杂,监督检查难以落实,指标分配不透明、下达时间晚等问题。本文对存在的问题进行分析,提出河北省国有林场要以森林经营方案控制采伐限额、取消消耗结构,简化采伐类型、引进林业专业人才,加强采伐管理和优化抚育采伐等方面改善森林采伐管理制度。     

Site-occupancy of bats in relation to forested corridors

Although use of corridors by some wildlife species has been extensively examined, use by bats is poorly understood. From 1 June to 31 August (2004–2005), we used Anabat II detectors to examine bat activity and species occupancy relative to forested corridors on an intensively managed forest landscape in southern South Carolina, USA. We compared bat activity among corridor interiors, corridor edges, and stands adjacent to corridors. We also compared models relating occupancy of bat species to site-level characteristics using an information theoretic approach. We identified 16,235 call sequences of 8 species and detected bat presence at 89% (n = 320) of sites sampled. Our results indicate higher occupancy rates for bats along corridor edges compared to interior corridor or adjacent stands. Although we found few differences among species with respect to site-level characteristics, occupancy of all bat species was positively associated with corridor overstory height and negatively associated with adjacent stand age. The presence of roads adjacent to corridors positively influenced occupancy of Eptesicus fuscus, Lasiurus seminolus, and Perimyotis subflavus. Our results suggest management practices designed to create and enhance corridors may represent an ecologically sound method for maintaining important bat habitat features (i.e., edge) across managed forest landscapes.     

改革单一产业结构建立工业多元化经营发展的新格局

本文论述了改革传统单一产业结构的必要性与必然性，提出建立以副以工养林、变副变工为主，全方位立体开发的新型产业结构。     

From clearfell coupe to old-growth forest: Succession of bird assemblages in Tasmanian lowland wet eucalypt forests

As forests undergo succession after major disturbance events their assemblages of birds also change. Thus the frequency and extent of wildfire or clearfelling in the landscape can potentially affect the species-richness and abundance of forest birds. We used a chronosequence approach to investigate succession of bird communities in Tasmanian lowland wet eucalypt forest, from shortly after disturbance through to old-growth forest aged approximately 200–250 years. The number of native bird species recorded per survey per site increased as a linear function of stand-age. However, succession did not involve a unidirectional transition in assemblage-composition because of differences in successional responses among individual species and also among guilds of birds that mostly inhabited different strata of the forest. This was exemplified by the crescent honeyeater, which was observed most frequently in the youngest (6–8 years) and oldest (200–250 years) forests that we surveyed, and by the superb lyrebird (introduced to Tasmania from mainland south-eastern Australia) which favoured mid-aged regrowth (42–43 years) after clearfelling. Forests aged 200–250 years had the greatest richness-per-survey of those native species that were observed mostly in the lower layer or mid-layer. However, the greatest richness-per-survey of canopy-dwelling species and the highest native species-richness across the survey period were found in forests aged around 150 years. Younger regrowth was generally less rich in birds, although regrowth in the first decade after clearfelling was the only seral stage inhabited by superb fairy-wrens. These results suggest that, in the Tasmanian lowland wet eucalypt forest landscape, species-richness of birds may be greatest when old-growth forest is interspersed with young regrowth forests. Hence for bird conservation, a challenge is to ensure that old-growth forest continues to prevail in the production forest landscape.     

Importance of forest structure versus floristics to composition of avian assemblages in tropical deciduous forests of Central Highlands,India

We investigated how much forest structure and floristics independently contributed to the composition of avian assemblages at multiple scales and for individual foraging guilds in tropical deciduous forests of Central Highlands, India. We derived dissimilarity matrices between all pairs of the 36 sampling sites with respect to forest structure, floristics, and bird species composition and ran Mantel's randomization tests to detect significant associations among the matrices after partialling out the effect of geographic distance between sites. Bird species composition was found to be significantly related to forest structure across habitats, and floristics within the moist-deciduous forests. This finding is consistent with earlier observations that birds respond, in their species composition, to vegetation structure across habitats and to vegetation composition within a habitat. As predicted, the composition of insectivorous birds was influenced by forest structure, but the phytophagous guild did not show any relation to vegetation composition in contrast to patterns observed elsewhere. We explain this anomaly as a result of availability of a wide choice of food plants for phytophagous birds in central Indian tropical forests and weak species–environment relationships on account of their nomadism. Extraction of non-timber forest products remains a key economic activity in central India and our results imply that it can potentially influence the composition of forest bird communities through alteration of forest structure and floristics.     

Object-based semi-automatic approach for forest structure characterization using lidar data in heterogeneous Pinus sylvestris stands

In this paper, we present a two-stage approach for characterizing the structure of Pinus sylvestris L. stands in forests of central Spain. The first stage was to delimit forest stands using eCognition and a digital canopy height model (DCHM) derived from lidar data. The polygons were then clustered (k-means algorithm) into forest structure types based on the DCHM data within forest stands. Hypsographs of each polygon and field data validated the separability of structure types. In the study area, 112 polygons of Pinus sylvestris were segmented and classified into five forest structure types, ranging from high dense forest canopy (850 trees ha⁻¹ and Loreýs height of 17.4 m) to scarce tree coverage (60 tree ha⁻¹ and Loreýs height of 9.7 m). Our results indicate that the best variables for the definition and characterization of forest structure in these forests are the median and standard deviation (S.D.), both derived from lidar data. In these forest types, lidar median height and standard deviation (S.D.) varied from 15.8 m (S.D. of 5.6 m) to 2.6 m (S.D. of 4.5 m). The present approach could have an operational application in the inventory procedure and forest management plans.     

An assessment of hydrological functions of forest ecosystems to support sustainable forest management

Forests are among the most important ecosystems that provide various hydrological services including water production and protection because the vast majority of the water available on the earth comes from forested catchments. The forests provide quality and continuous water yield as well as protective services such as flood control, soil protection, landslide protection, avalanche protection, and prevention against rock falls, which are related to water. However, the quality and quantity of all the forest functions are influenced by forest ecosystem structure and composition such as forest type, tree species, age class distribution, biomass, leaf area, basal area, crown closure, and stand development stages. This study provides an assessment of hydrological services of forest ecosystems through the systematic review of relevant literature till 2018. It mainly focuses on water-forest relations and explains how forest ecosystem structure and composition affect water production, quality, and sustainability. Then, a general framework relating to the integration of hydrological services into forest management is concluded in the context of sustainable management of natural resources.