Saproxylic beetles in high stumps and residual downed wood on clear-cuts and in forest edges

Abstract

This study evaluates how the placement and the different possible outcomes of a spruce retention tree affected species richness and assemblages of spruce-associated saproxylic beetles. In a field experiment in the boreal zone of central Norway, high stumps were created and compared with residual wood pieces (i.e. top boles with branches), in clear-cuts versus in forest edges. Flight interception traps were mounted close to the substrate. The results were analysed using rarefaction techniques, ordination (DCA) and anova. It was found that the placement of retention trees of spruce does matter: beetle assemblages were significantly different in stumps in the four treatments. For all species pooled, the species richness was higher in stumps in clear-cuts than in stumps or boles in the forest edge. Four red-listed species were more abundant near stumps than boles, and two red-listed species were more abundant in clear-cuts than forest edge. To cater for the variety of habitat preferences among forest beetles in managed forest, managers should leave both standing spruce trees (many of which will end up as windthrown, downed boles) and some high stumps (to secure some upright dead wood), in both exposed clear-cut and semi-shaded forest edge.     

A forest of grazing and logging: Deforestation and reforestation history of a boreal landscape in central Sweden

Detailed spatial changes in foreststructure in a central Swedish landscape were examinedusing geographic information system techniques. First,the influence of grazing and burning on forest densityand structure in the 19th century landscape wereanalyzed. Then, the development of the landscapeduring the 20th century, together with the impactof modern forest management methods on foreststructure, were analyzed using historical sources. In1907, over 20% of the 2200 hectare study site wassparsely-wooded (12 m³ ha^–1) with old trees.These areas have been reforested with single-storiedmiddle-aged and old pine stands (66 m³ ha^–1in 1989) during the 20th century. Firesuppression and changes in land use from subsistence-to-industrialforestry, facilitated Norway spruceregeneration as undergrowth in open Scots pine standsafter logging. This natural regeneration has, to alarge extent, been cut down and replaced by pineafforestation. During the second half of the 20thcentury, the standing timber volume has steadilyincreased, while the mean age of the forest hasdecreased. Today's young dense forests will result inhigher timber values in the coming decades, but theforest has lost a range of ecological niches.     

兴安落叶松天然林2种林型林分更新特征

分析了内蒙古大兴安岭林分结构对兴安落叶松林更新的影响。结果表明:1)年龄56~65 a草类-落叶松林平均更新密度达1 363株/hm2,较54~63 a杜香-落叶松林和36~48 a草类-落叶松林分别高12.8%,36.5%。2)年龄36~65 a,密度315~3 263株/hm2范围内的草类-落叶松和年龄54~63 a密度865~2 241株/hm2范围内的杜香-落叶松林,在其它条件相近情况下,随着林分年龄和密度增加,林分更新呈增加趋势;随着枯倒木数量和其腐烂程度的增加,更新密度增加;随着林下草本和灌木盖度增加,更新密度呈下降趋势。3)不同水平格局的林分更新不同,当聚集分布、随机分布和均匀分布时,平均更新密度分别为1 415株/hm2,1 165株/hm2,118株/hm2。     

Airborne laser scanning as a method in operational forest inventory: Status of accuracy assessments accomplished in Scandinavia

Abstract

This research reports the major evaluation results from an operational stand-based forest inventory using airborne laser scanner data carried out in Norway. This is the first operational inventory in which data from two separate districts are combined. Laser data from two forest areas of 65 and 110 km² were used to predict six biophysical stand variables used in forest planning. The predictions were based on regression equations estimated from 250 m² field training plots distributed systematically throughout the two forest areas. Test plots with a size of 0.1 ha were used for validation. The testing revealed standard deviations between ground-truth values and predicted values of 0.58–0.85 m (3.4–5.6%) for mean and dominant heights, 2.62–2.87 m² ha^?1 (9.3–14.3%) for basal area, and 18.7–25.1 m³ ha^?1 (10.8–12.8%) for stand volume. No serious bias was detected. For 10 of the 12 estimated regression models there were no significant effects of district.     

Timber tree regeneration along abandoned logging roads in a tropical Bolivian forest

Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north-eastern Bolivia. Some species benefited from increased light intensities on abandoned logging roads. Others benefited from low densities of competing vegetation on roads with compacted soils. This was the case for the small-seeded species Ficus boliviana C.C. Berg and Terminalia oblonga (Ruiz & Pav.) Steud. Some species, e.g. Hura crepitans L., displayed patchy regeneration coinciding with the presence of adult trees. Our results suggest that current management practices could be improved by intensifying logging in some areas to improve regeneration of light demanding species. Sufficient seed input in logged areas should be ensured by interspersing large patches of unlogged forest with logged areas. This may also assist regeneration of species that perform poorly in disturbed areas.     

The impact of community-based forest management on timber treeregeneration in north-eastern Honduras,with specific reference tobig-leaf mahogany (Swietenia macrophylla)

Reduced-impact logging is used to minimise the negative effects of selective logging. However, it has been suggested that low-impact logging may create too little disturbance for the regeneration of the light-demanding timber tree species, hence compromising forest productivity. This study evaluates the impact of low-intensity, non-mechanised, certified community forest management on timber tree regeneration. Particular attention was paid to big-leaf mahogany (Swietenia macrophylla), which has a regeneration pattern linked with large-scale disturbances. Logging gaps were compared to natural treefall gaps of an unlogged forest. There were more species of the light-demanding timber trees, but fewer individuals of the shade-tolerant timber species in the certified forest logging gaps, compared to unlogged forest treefall gaps. Furthermore, significant differences were found in the environmental characteristics of the logging and natural treefall gaps, although these only partially explained the differences in timber regeneration. Mahogany was found in over half of the logged forest gaps, whilst being nearly absent in the natural treefall gaps. However, all mahoganies in the established logging gaps were seedling-sized, indicating that regeneration may be hampered due to competing vegetation. The results of the study suggest that low-impact forest management may, at least in the short term, favour light-demanding species over the shade-tolerant ones, similarly to conventional forest management.     

林隙及其对天然林更新的影响

林隙是森林中由自然或人为小规模干扰形成的,是森林演替和循环中必不可少而又经常发生的现象,为森林的更新提供了有利的微环境。本文通过对林隙尺度、特征和森林微环境变化等叙述,重点分析了我国对天然林林隙的研究现状、分布的区域和森林类型,林隙大小、年龄和边缘木等方面对天然林更新的影响,以及林隙理论在实践中的应用,指出,林隙更新理论是森林经营,尤其是天然林经营中最重要的方面之一。     

对森林认证及其在少林省份开展的认识与思考

目前森林认证已经成为世界和我国林业部门、森林经营单位关注的热点问题之一。森林认证已经成为世界林业的新趋势之一。通过对世界森林认证历史发展的分析,全面了解我国的认证工作,结合作者参加山东省速生人工林森林认证的经验,对在速生人工林认证期间遇到的困难进行梳理,并提出了解决方法和建议。希望能探索出少林省份在开展森林认证的适宜办法,努力使少林省份林业得到全面协调可持续的科学发展。     

Assessment of motivation and attitudes of forest industry companies toward forest certification in northwestern Russia

This study explores for the first time the attitudes and motivation associated with forest certification among forest industry companies in northwestern Russia. Interviews were carried out in the form of a structured questionnaire including 35 forest industry companies operating in northwestern Russia. Although development of certification in individual companies was initiated by general market demand, representatives of certified companies also emphasized the importance of internal corporate policy. Certified and noncertified groups of respondents identified market demand as a main driving force influencing development of forest certification. Ensuring the legality of wood origin, company's image and competitiveness of wood products were recognized as the most important benefits associated with forest certification. Absence of mandatory requirements from authorities and customers appeared to be the largest obstacle among both groups of respondents. Representatives of noncertified companies pointed out economic inaccessibility and low level of preparedness of management as of high importance, which is mainly associated with absence of quality management system. The results of the study indicated a general positive attitude on forest certification; it was noticed that respondents have gaps in understanding the principles and limited awareness with regards to forest certification, especially among noncertified forest industry companies.     

子午岭油松林林隙更新特征研究

利用样地调查资料,以林下为对照,分析研究子午岭油松林的林隙更新特征,结果表明:1)子午岭油松林林隙内和林下更新树种在组成和数量上有较大差异,其中,油松在林隙内的重要值远远大于其在林下的重要值,是林隙更新的主要树种;2)油松幼苗幼树在林隙内生长良好,7年生以上的幼树在林下分布已很少,地径在1.0cm以上、高度在50cm以上的幼树数量分布在林隙内也远远大于林下,说明随着年龄的增长,油松幼苗幼树在林隙内存活的概率大于林下;3)方差分析表明,油松幼苗幼树在林隙内与林下的高度生长差异极为显著;4)相关性分析表明,林隙内油松幼苗幼树的更新数量与光照强度呈显著正相关,与植被总盖度呈显著负相关。     

Laser scanning of forest resources: the nordic experience

This article reviews the research and application of airborne laser scanning for forest inventory in Finland, Norway and Sweden. The first experiments with scanning lasers for forest inventory were conducted in 1991 using the FLASH system, a full-waveform experimental laser developed by the Swedish Defence Research Institute. In Finland at the same time, the HUTSCAT profiling radar provided experiences that inspired the following laser scanning research. Since 1995, data from commercially operated time-of-flight scanning lasers (e.g. TopEye, Optech ALTM and TopoSys) have been used. Especially in Norway, the main objective has been to develop methods that are directly suited for practical forest inventory at the stand level. Mean tree height, stand volume and basal area have been the most important forest mensurational parameters of interest. Laser data have been related to field training plot measurements using regression techniques, and these relationships have been used to predict corresponding properties in all forest stands in an area. Experiences from Finland, Norway and Sweden show that retrieval of stem volume and mean tree height on a stand level from laser scanner data performs as well as, or better than, photogrammetric methods, and better than other remote sensing methods. Laser scanning is, therefore, now beginning to be used operationally in large-area forest inventories. In Finland and Sweden, research has also been done into the identification of single trees and estimation of single-tree properties, such as tree position, tree height, crown width, stem diameter and tree species. In coniferous stands, up to 90% of the trees represented by stem volume have been correctly identified from canopy height models, and the tree height has been estimated with a root mean square error of around 0.6 m. It is significantly more difficult to identify suppressed trees than dominant trees. Spruce and pine have been discriminated on a single-tree level with 95% accuracy. The application of densely sampled laser scanner data to change detection, such as growth and cutting, has also been demonstrated.     

How financial compensation changes forest owners' willingness to set aside productive forest areas for nature conservation in Denmark

Abstract

Agri-environmental schemes' ability to increase the provision of environmental goods has been questioned because such schemes may pay landowners for something they would have done anyway. Contributing to this discussion, the aim of this paper is to investigate how financial compensation changes forest owners' declared willingness to set aside productive forest areas for nature conservation. The study is based on a survey of forest owner attitudes and ownership objectives in Denmark. First, it was analyzed how forest owners' declared willingness to set aside productive forest area for nature conservation changed when they were offered financial compensation. The majority of forest owners (64%) increased their willingness to set aside forest when offered financial compensation, whereas for others, compensation resulted in no change or, for a few respondents, even decreased the willingness. Hence, financial compensation may help to increase the provision of environmental goods but it is necessary to be aware of groups not motivated by financial incentives. Secondly, a binary logit model showed that the greatest likelihood of financial compensation increasing the motivation for setting aside forest is observed for owners who are young, female, live in the western part of Denmark and own farmland. Policy makers can use such information to target subsidy schemes at particular groups.     

天然阔叶林皆伐迹地人工封促成林试验研究

本文通过天然阔叶林皆伐迹地，采用人工封促成林与自然更新二种不同更新方法的对比试验，结果表明：采用人工封促成林的更新方法具有明显的优点，即投资少，效益大，林木生长快，单位面积蓄积量可提高５０．７％；建议有条件的地方应推广使用该方法。为发展阔叶林生产，保持生态平衡提供了一条有效的途径。     

Small area estimation of forest attributes in the Norwegian National Forest Inventory

The Norwegian National Forest Inventory (NNFI) provides estimates of forest parameters on national and regional scales by means of a systematic network of permanent sample plots. One of the biggest challenges for the NNFI is the interest in forest attribute information for small sub-populations such as municipalities or protected areas. Frequently, too few sampled observations are available for such small areas to allow estimates with acceptable precision. However, if an auxiliary variable exists that is correlated with the variable of interest, small area estimation (SAE) techniques may provide means to improve the precision of estimates. The study aimed at estimating the mean above-ground forest biomass for small areas with high precision and accuracy, using SAE techniques. For this purpose, the simple random sampling (SRS) estimator, the generalized regression (GREG) estimator, and the unit-level empirical best linear unbiased prediction (EBLUP) estimator were compared. Mean canopy height obtained from a photogrammetric canopy height model (CHM) was the auxiliary variable available for every population element. The small areas were 14 municipalities within a 2,184 km² study area for which an estimate of the mean forest biomass was sought. The municipalities were between 31 and 527 km² and contained 1–35 NNFI sample plots located within forest. The mean canopy height obtained from the CHM was found to have a strong linear correlation with forest biomass. Both the SRS estimator and the GREG estimator result in unstable estimates if they are based on too few observations. Although this is not the case for the EBLUP estimator, the estimators were only compared for municipalities with more than five sample plots. The SRS resulted in the highest standard errors in all municipalities. Whereas the GREG and EBLUP standard errors were similar for small areas with many sample plots, the EBLUP standard error was usually smaller than the GREG standard error. The difference between the EBLUP and GREG standard error increased with a decreasing number of sample plots within the small area. The EBLUP estimates of mean forest biomass within the municipalities ranged between 95.01 and 153.76 Mg ha^?1, with standard errors between 8.20 and 12.84 Mg ha^?1.     

呼伦贝尔沙地樟子松天然更新苗影响因素的研究

通过对呼伦贝尔沙地樟子松天然林天然更新苗特征及其影响因素的研究,结果表明:母树密度不同,天然更新苗数量和年龄结构存在明显差异;樟子松天然更新苗年龄结构在时间上具有明显的不连续性,樟子松天然更新苗密度因林分类型的差异明显不同。在疏林地(树龄30 a),平均更新苗密度每2 500 m2为13株,在火烧迹地平均更新苗密度每600 m2为28.5株,樟子松单株样地平均更新苗密度每600 m2为118.8株。不同年龄的天然更新苗保存密度和年平均降水量有显著或极显著关系,且随着林分郁闭度的增加,研究区天然更新苗密度呈现降低的趋势。     

Timber production possibilities of the Norwegian forest area and measures for a sustainable forestry

This paper presents long-range forest management analyses with the objective of mapping consequences for the timber production potential when forest management treatments are changed in an environmentally oriented direction. Sample plots from the National Forest Inventory, covering the entire productive forest area in Norway, were aggregated into 10000 treatment units. Management strategies maximising the net present value of the forest-land, with certain environmentally oriented constraints, were analysed. The following environmentally oriented constraints were considered: (i) areas of current old forest set aside, either proportionally or cost-efficiently, for permanent preservation, (ii) minimum target levels for area covered by old forest through time, (iii) retention of trees at final felling, and (iv) restricted management for border zone areas. With a real rate of discount of 2.5%, and all the constraints imposed simultaneously, the annual harvest potential was reduced by 30% for the first 10-year period, while the net present value was reduced by 21.5%. The results further demonstrated significant efficiency gains of letting the preservation of old forest be allocated cost-efficiently, compared with a strategy of setting aside an equal portion on all eligible areas.     

Site requirements of the endangered rosewood Dalbergiaoliveri in a tropical deciduous forest in northern Thailand

Planting native trees may complement and accelerate natural regeneration and support recovery of biodiversity in degraded forests. Before planting trees, however, there is a need for species-specific site selection criteria. This study investigates the site requirements of a valuable but endangered rosewood species, Dalbergia oliveri, with the purpose of restoring degraded deciduous forest in northern Thailand.     

Bioenergy from the forest sector: Economic potential and interactions with timber and forest products markets in Norway

Abstract

A partial equilibrium forest sector model which is augmented to include bioenergy was applied to project the use of bioenergy based on forest fuels and forest industry by-products in Norway for three different scenarios of the future prices of electricity and oil. The impacts on forestry and forest industries of the different energy price scenarios were also studied. The advantage of the suggested methodology is that it allows for assessments of the economic potential of bioenergy, taking into account the competition for raw materials, the specific heat demand of various regions, and interregional and international trade. Bioenergy will, according to this study, be fairly competitive in some market segments with the current price levels of electricity and oil, and only a minor increase (decrease) in energy (roundwood) prices would release substantially increased bioenergy production levels. Pulpwood prices of pine and non-coniferous species are projected to increase substantially when assuming increasing energy prices. Except for particleboard mills, production levels of forest industries appeared relatively insensitive to the energy price changes.     

Boundaries of transnational forest governance in Russia

Abstract

The article examines how both the territorial and non-territorial boundaries affect the transnational forest governance. Although being a globalised and transnational feature, present forest governance is shaped, enabled and restricted by various kinds of boundaries. The transnational forest governance is approached as a process which operates through both borderless network-spaces and bounded regional spaces. The article scrutinises empirically how the transnational forest governance has entered the Russian woodlands. The operations of multinational forestry companies, campaigns of transnational ENGOs and systems of forest certification have connected some parts of Russia with novel transnational network-spaces of forest governance. The main argument is, however, that regional spaces and boundaries influence and afford the processes of transnational forest governance in numerous ways.