林业剩余物资源量评估方法

根据近十年来相关文献报道,分析了前人所建方法的合理性,结合中国林业生产实际,完善了林业剩余物资源潜力的计算方法。主要贡献包括:林业剩余物第二级分类的10个主要类型,即林木苗圃剩余物、林木修枝剩余物、木材采伐剩余物、木材造材剩余物、木材加工剩余物、竹材加工剩余物、薪材、废旧竹材、废旧木材、香蕉和菠萝残体;将经济林采伐和进口原木产生的剩余物计入相关木材剩余物计算范围;首次建立了包括木本水果在内的林木修枝剩余物的计算方法,以及多年生草本水果剩余物即香蕉和菠萝残体产量的计算方法;确定计算公式中参数所需要数据的来源;建议今后重点研究相关系数取值、林业剩余物资源量及其空间分布和相关行业标准等。     

Short‐term growth response of jack pine and spruce spp. to wood ash amendment across Canada

Wood ash amendment to forest soils contributes to the sustainability of the growing bioenergy industry, not only through decreased wood ash waste disposal in landfills but also by increasing soil/site productivity and tree growth. However, tree growth studies to date have reported variable responses to wood ash, highlighting the need to identify proper application rates under various soil/site conditions to maximize their benefits. We explored the influence of tree species, wood ash nutrient application rates, time since application, stand development stage, and initial (i.e., before wood ash application) soil pH and N on short‐term tree growth response to wood ash amendment across eight unique study sites spanning five Canadian Provinces. Jack pine (Pinus banksiana Lamb) had the most positive response to wood ash amendment compared to white (Picea glauca Moench), hybrid (Picea engelmannii x glauca Parry), and black spruce (Picea mariana Miller), where increasing nutrient application rates increased height growth response. In comparison, black spruce had the most negative response to wood ash amendment, where increasing nutrient application rates slightly decreased height growth response. Site as a random effect explained additional variation, highlighting the importance of other unidentified site characteristics. By examining trends in short‐term growth response across multiple studies with variable site characteristics, we found growth response differed by tree species and nutrient application rates, and that jack pine is a promising candidate for wood ash amendment. These results contribute to our knowledge of optimal wood ash amendment practices and environmentally sustainable bioenergy production.     

Status and prospects for renewable energy using wood pellets from the southeastern United States

The ongoing debate about costs and benefits of wood‐pellet based bioenergy production in the southeastern United States (SE USA) requires an understanding of the science and context influencing market decisions associated with its sustainability. Production of pellets has garnered much attention as US exports have grown from negligible amounts in the early 2000s to 4.6 million metric tonnes in 2015. Currently, 98% of these pellet exports are shipped to Europe to displace coal in power plants. We ask, ‘How is the production of wood pellets in the SE USA affecting forest systems and the ecosystem services they provide?’ To address this question, we review current forest conditions and the status of the wood products industry, how pellet production affects ecosystem services and biodiversity, and what methods are in place to monitor changes and protect vulnerable systems. Scientific studies provide evidence that wood pellets in the SE USA are a fraction of total forestry operations and can be produced while maintaining or improving forest ecosystem services. Ecosystem services are protected by the requirement to utilize loggers trained to apply scientifically based best management practices in planning and implementing harvest for the export market. Bioenergy markets supplement incomes to private rural landholders and provide an incentive for forest management practices that simultaneously benefit water quality and wildlife and reduce risk of fire and insect outbreaks. Bioenergy also increases the value of forest land to landowners, thereby decreasing likelihood of conversion to nonforest uses. Monitoring and evaluation are essential to verify that regulations and good practices are achieving goals and to enable timely responses if problems arise. Conducting rigorous research to understand how conditions change in response to management choices requires baseline data, monitoring, and appropriate reference scenarios. Long‐term monitoring data on forest conditions should be publicly accessible and utilized to inform adaptive management.     

Saproxylic beetle diversity in a managed boreal forest: importance of stand characteristics and forestry conservation measures

Saproxylic beetles constitute a significant proportion of boreal forest biodiversity. However, the long history of timber production in Fennoscandia has significantly reduced the availability of dead wood and is considered a threat to the conservation of saproxylic beetle assemblages. Therefore, since the mid‐1990s dead wood retention in harvested stands has formed an integral part of silvicultural practices. However, the contribution of this biodiversity‐orientated management approach to conserving saproxylic beetle assemblages in boreal forest landscapes that include production forestry remains largely untested. We examined differences in resident saproxylic beetle assemblages among stands under different management in a boreal forest landscape in Central Sweden, and in particular stands managed according to new conservation‐orientated practices. We also investigated the relationship between beetle diversity and forest stand characteristics. Bark of coarse woody debris (CWD) was sieved for beetles in old managed stands, unmanaged nature reserves, and set‐aside areas, and clear‐cut stands harvested according to certification guidelines [new forestry (NF) clear‐cuts]. All stand types contributed significantly to the total diversity of beetles found. While stand size, position, and distance to nearest reserve were unimportant, both the quality and the quantity of CWD in stands contributed significantly to explaining beetle abundance and species richness. This extends the previous findings for red‐listed invertebrates, and shows that heterogeneous substrate quality and a range of management practices are necessary to maintain saproxylic beetle diversity in boreal forest landscapes that include production forestry. The unique abiotic conditions in combination with the abundant and varied CWD associated with NF clear‐cuts form an important component of forest stand heterogeneity for saproxylic beetles. It is thus essential that sufficient, diverse, CWD is retained in managed boreal landscapes to ensure the conservation of boreal saproxylic beetle assemblages.     

Sustainability impact assessment of increasing resource use intensity in forest bioenergy production chains

Changing forest management practices towards more intensive biomass utilization for energy purposes will affect the sustainability of resource management. The Tool for Sustainability Impact Assessment was applied to evaluate the environmental, social, and economic sustainability impacts of the stepwise increased extraction of forest biomass of three typical Scandinavian Scots pine bioenergy production chains (BPCs). The assessed sources of the woody biomass were pellets as a by‐product of the sawmilling industry, wood chips deriving from early whole‐tree harvesting, and residues from final cuttings. Three commercially practiced BPCs were compared. By the additional extraction of biomass for heat production, the employment increased by 0.6 person‐years 1000 m^?3 solid wood chips, while there was a decrease in the costs and greenhouse gases emitted per unit of heat consumed. Furthermore this practice did not only add positive socio‐economic but also positive environmental impacts on sustainability, particularly on the greenhouse gas balance and the energy efficiency ratio (input to output ratio along the BPC), which was determined to be 1–24. Potential drawbacks, on the other hand, include decreasing nutrient returns to the soil and the associated potential reduction in future stand productivity. Fertilization might be needed to maintain sustainable forest growth on poor sites.     

Characteristics of wood ash and influence on soil properties and nutrient uptake: an overview

Wood industries and power plants generate enormous quantities of wood ash. Disposal in landfills has been for long a common method for removal. New regulations for conserving the environment have raised the costs of landfill disposal and added to the difficulties for acquiring new sites for disposal. Over a few decades a number of studies have been carried out on the utilization of wood ashes in agriculture and forestry as an alternative method for disposal. Because of their properties and their influence on soil chemistry the utilization of wood ashes is particularly suited for the fertility management of tropical acid soils and forest soils. This review principally focuses on ash from the wood industry and power plants and considers its physical, chemical and mineralogical characteristics, its effect on soil properties, on the availability of nutrient elements and on the growth and chemical composition of crops and trees, as well as its impact on the environment.     

Producing wood at least cost to biodiversity: integrating Triad and sharing–sparing approaches to inform forest landscape management

Forest loss and degradation are the greatest threats to biodiversity worldwide. Rising global wood demand threatens further damage to remaining native forests. Contrasting solutions across a continuum of options have been proposed, yet which of these offers most promise remains unresolved. Expansion of high-yielding tree plantations could free up forest land for conservation provided this is implemented in tandem with stronger policies for conserving native forests. Because plantations and other intensively managed forests often support far less biodiversity than native forests, a second approach argues for widespread adoption of extensive management, or ‘ecological forestry’, which better simulates natural forest structure and disturbance regimes – albeit with compromised wood yields and hence a need to harvest over a larger area. A third, hybrid suggestion involves ‘Triad’ zoning where the landscape is divided into three sorts of management (reserve, ecological/extensive management, and intensive plantation). Progress towards resolving which of these approaches holds the most promise has been hampered by the absence of a conceptual framework and of sufficient empirical data formally to identify the most appropriate landscape-scale proportions of reserves, extensive, and intensive management to minimize biodiversity impacts while meeting a given level of demand for wood. In this review, we argue that this central challenge for sustainable forestry is analogous to that facing food-production systems, and that the land sharing–sparing framework devised to establish which approach to farming could meet food demand at least cost to wild species can be readily adapted to assess contrasting forest management regimes. We develop this argument in four ways: (i) we set out the relevance of the sharing–sparing framework for forestry and explore the degree to which concepts from agriculture can translate to a forest management context; (ii) we make design recommendations for empirical research on sustainable forestry to enable application of the sharing–sparing framework; (iii) we present overarching hypotheses which such studies could test; and (iv) we discuss potential pitfalls and opportunities in conceptualizing landscape management through a sharing–sparing lens. The framework we propose will enable forest managers worldwide to assess trade-offs directly between conservation and wood production and to determine the mix of management approaches that best balances these (and other) competing objectives. The results will inform ecologically sustainable forest policy and management, reduce risks of local and global extinctions from forestry, and potentially improve a valuable sector's social license to operate.     

日本演习林制度对中国生物多样性保护与国家公园建设的启示

演习林是日本通过农林院校管辖和运行的自然林地与人工林, 兼具科教、生物多样性保护、生态旅游与林木生产等功能。演习林的责、权、利明确, 能够实现长期、稳定的保护与利用, 与自然保护区、国家公园既有区别又相辅相成, 是日本经济协调发展与快速实现生态恢复的一个重要保障。目前, 日本约有30所高等院校拥有演习林, 演习林面积约占日本森林总面积的5‰, 其中东京大学的演习林建立最早、运行与管理机制最为完善。演习林主要有三大功能: 教学实践、科学研究、社会服务。演习林主要负责人是大学教师, 教师既参与科教也参与管理, 实现了教授治校、科教与社会服务的协调发展。当前, 我国正处于生物多样性保护的转型期和国家公园试点建设的关键阶段, 农林类高校或研究所可借鉴日本演习林制度, 主动参与到国家“绿水青山就是金山银山”的绿色发展理念和实践中; 涉及生物学与农林学科的科学工作者应积极承担当地自然保护区、森林公园、国家公园等的建设与管护。政府可以引导和吸纳有着充足研究经费、学术水平较高的农林与生物学类高校(特别是相关学科被列入“世界一流学科”建设行列的高校)在有条件的自然保护区或城市周边开辟高校直辖林地, 实现教学实践、研究与保护、社会服务等共建共存模式, 提升我国高校农林与生物学科研究水平, 促进我国生物多样性的可持续保护和国家公园的高标准建设。     

Forest biomass,soil and biodiversity relationships originate from biogeographic affinity and direct ecological effects

Ecosystem biomass, soil conditions and the diversity of different taxa are often interrelated. These relationships could originate from biogeographic affinity (varying species pools) or from direct ecological effects within local communities. Disentangling regional and local causes is challenging as the former might mask the latter in natural ecosystems with varying habitat conditions. However, when the species pool contribution is considered in statistics, local ecological effects might be detected. In this study we disentangle the indirect effects of the species pool and direct ecological effects on the complex relationships among wood volume, soil conditions and diversities of different plant and fungal groups in 100 old‐growth forest sites (10 × 10 m) at the border of boreal and nemoral zones in northern Europe. We recorded all species for different vegetation groups: woody and herbaceous vascular plants, terricolous and epiphytic bryophytes and lichens. Fungal communities were detected by DNA‐based analyses from soil samples. Above‐ground wood volume was used as a proxy of biomass. We measured soil pH and nutrient content and obtained modelled climate parameters for each site. Species pool effect was considered by dividing sites into boreal and nemoral groups based on community composition. In order to disentangle direct and indirect effects, we applied variation partitioning, and raw and partial correlations. We found many significant positive relationships among studied variables. Many of these relationships were associated to boreal and nemoral species pools, thus indicating that biogeographic affinity of interacting plants and fungi largely defines forest diversity and functioning. At the same time, several relationships were significant also after considering biogeography: woody plant and ectomycorrhizal fungi diversities with wood volume, many plant and fungal groups with each other, or with soil conditions. These direct ecological interactions could be considered in forestry practices to achieve both economic gain and maintenance of biodiversity.     

Effects of intensified forestry on the landscape-scale extinction risk of dead wood dependent species

In the future, a significant proportion of Northern forests may become intensively managed through the planting of monospecific stands of native or introduced trees, and the use of multiple silvicultural treatments such as forest fertilization. Such an intensification of management in selected parts of the landscape is suggested by different zoning models, for example the Triad approach, which is under evaluation in some regions of North America. In this study, based on Fennoscandian conditions, we predicted landscape-scale extinction risks of five hypothetical model insect species dependent on fresh dead wood from Norway spruce (Picea abies), by simulating colonizations and local extinctions in forest stands. Intensified forestry applied to 50% of the spruce stands led to strongly increased extinction risks of all species during the following 150 years. For one species—the sun-exposure specialist—there were strong effects already after 50 years. The negative effects of intensive plantation forestry could be compensated for by taking greater biodiversity conservation measures in other managed forests or by setting aside more forests. This is consistent with the Triad model, which is according to our analyzes an effective way to decrease extinction risks, especially for the short-dispersing species and the species associated with closed forest. A zoning of forest land into intensive forestry, conventional forestry, and set asides may be better at combining increased timber production and maintenance of biodiversity in comparison to landscapes where all production forests are managed in the same way.     

Evaluating the effectiveness of retention forestry to enhance biodiversity in production forests of Central Europe using an interdisciplinary,multi‐scale approach

Retention forestry, which retains a portion of the original stand at the time of harvesting to maintain continuity of structural and compositional diversity, has been originally developed to mitigate the impacts of clear‐cutting. Retention of habitat trees and deadwood has since become common practice also in continuous‐cover forests of Central Europe. While the use of retention in these forests is plausible, the evidence base for its application is lacking, trade‐offs have not been quantified, it is not clear what support it receives from forest owners and other stakeholders and how it is best integrated into forest management practices. The Research Training Group ConFoBi (Conservation of Forest Biodiversity in Multiple‐use Landscapes of Central Europe) focusses on the effectiveness of retention forestry, combining ecological studies on forest biodiversity with social and economic studies of biodiversity conservation across multiple spatial scales. The aim of ConFoBi is to assess whether and how structural retention measures are appropriate for the conservation of forest biodiversity in uneven‐aged and selectively harvested continuous‐cover forests of temperate Europe. The study design is based on a pool of 135 plots (1 ha) distributed along gradients of forest connectivity and structure. The main objectives are (a) to investigate the effects of structural elements and landscape context on multiple taxa, including different trophic and functional groups, to evaluate the effectiveness of retention practices for biodiversity conservation; (b) to analyze how forest biodiversity conservation is perceived and practiced, and what costs and benefits it creates; and (c) to identify how biodiversity conservation can be effectively integrated in multi‐functional forest management. ConFoBi will quantify retention levels required across the landscape, as well as the socio‐economic prerequisites for their implementation by forest owners and managers. ConFoBi's research results will provide an evidence base for integrating biodiversity conservation into forest management in temperate forests.     

Co‐benefits,trade‐offs,barriers and policies for greenhouse gas mitigation in the agriculture,forestry and other land use (AFOLU) sector

The agriculture, forestry and other land use (AFOLU) sector is responsible for approximately 25% of anthropogenic GHG emissions mainly from deforestation and agricultural emissions from livestock, soil and nutrient management. Mitigation from the sector is thus extremely important in meeting emission reduction targets. The sector offers a variety of cost‐competitive mitigation options with most analyses indicating a decline in emissions largely due to decreasing deforestation rates. Sustainability criteria are needed to guide development and implementation of AFOLU mitigation measures with particular focus on multifunctional systems that allow the delivery of multiple services from land. It is striking that almost all of the positive and negative impacts, opportunities and barriers are context specific, precluding generic statements about which AFOLU mitigation measures have the greatest promise at a global scale. This finding underlines the importance of considering each mitigation strategy on a case‐by‐case basis, systemic effects when implementing mitigation options on the national scale, and suggests that policies need to be flexible enough to allow such assessments. National and international agricultural and forest (climate) policies have the potential to alter the opportunity costs of specific land uses in ways that increase opportunities or barriers for attaining climate change mitigation goals. Policies governing practices in agriculture and in forest conservation and management need to account for both effective mitigation and adaptation and can help to orient practices in agriculture and in forestry towards global sharing of innovative technologies for the efficient use of land resources. Different policy instruments, especially economic incentives and regulatory approaches, are currently being applied however, for its successful implementation it is critical to understand how land‐use decisions are made and how new social, political and economic forces in the future will influence this process.     

Environmental impacts of forest production and supply of pulpwood: Spanish and Swedish case studies

Background, aim and scope  Forest operations use large amounts of energy, which must be considered when life cycle assessment (LCA) methodology is applied to forest products. Forest management practices differ considerably between countries and may also differ within a country. This paper aims to identify and compare the environmental burdens from forest operations in Sweden and Spain focused on pulpwood production and supply to pulp mills. Materials and methods  To perform the analysis, the main forest plantations were investigated as well as the most important tree species used in pulp mills in both countries: eucalyptus and, Norway spruce and Scots pine, were taken into account for the Spanish and Swedish case studies, respectively. Energy requirements for pulpwood production and supply to Spanish and Swedish pulp mills are evaluated in this paper. All forest operations from site preparation to extraction of felled wood to the delivery point at the roadside are included within the system boundaries as well as wood transport from forest landing to the pulp mill gate. Seedling and machinery production are excluded from the system boundaries due to lack of field data. The impact assessment phase was carried out according to the Swedish Environmental Management Council and, in particular, the impact categories assessed in forest and agricultural LCAs (global warming, acidification, eutrophication and photochemical oxidant formation) were analysed. SimaPro 7.10 software was used to perform the impact assessment stage. Results  Different types of wood are produced in both case studies: softwood in Sweden and hardwood in Spain, with higher production of round wood and biomass per hectare in Sweden. Total energy use for pulpwood production and supply are in a similar order of magnitude, up to 395 MJ and 370 MJ/m³ solid under bark in Spain and Sweden, respectively. Field operations, such as silviculture and logging, are more energy-intensive in the Spanish case study. However, secondary hauling of pulpwood to pulp mill requires more energy in the Swedish case study. These important differences are related to different forest management practices as well as to pulpwood supply to the pulp mill. The eventual imports of pulpwood, application of pesticides, thinning step or final felling considerably affects energy requirements, which are reflected on the environmental results. Discussion  Although differences between both case studies were observed, several stages were investigated: wood delivery to the pulp mill by road, harvesting and forwarding, contribute considerably to acidification, eutrophication and global warming potential in both cases. The type of wood, the machines used in forest operations (mechanised or motor-manual), the use of fossil fuels and the amount of wood produced influence the results. These differences must be kept in mind in comparative studies between such different countries. Conclusions  The results obtained in this work allow one to forecast the importance of forest operations in LCA of forest products (in this case, wood pulp) and the influence of energy use in the results. Special attention has been paid in the inventory analysis stage for both case studies. It is possible to gain a better environmental performance in both case studies if alternative practices are considered, mainly focused on site preparation and stand tending in the Spanish system and on pulpwood supply in the Swedish one. Recommendations and perspectives  This study provides useful information that can assist forest-based industries in the aim of increasing their sustainability. Future work will focus on the study of several transport alternatives of pulpwood supply including railway, road and ship. In addition, pulpwood processing in Spanish and Swedish paper pulp mills considered to be representative of the “state of art” will be carried out in order to get a complete picture of this kind of forest-based industry. In addition, the use of biofuels (such as forest biomass) instead of fossil fuels and CO₂ uptake of wood via photosynthesis will be carried out in order to have a complete perspective of forest ecosystems.     

The importance of substrate type, shading and scorching for the attractiveness of dead wood to saproxylic beetles

Modern forestry management has reduced the amount of dead wood in forest ecosystems and this has become a serious threat to flora and fauna. Efforts are therefore being made to reverse this trend but one problem is that we still lack detailed knowledge regarding the substrate requirements of many saproxylic species. In a field experiment, conducted in three forest types (forest reserve, mature managed forest and clear-cut), we evaluated the value, from a conservation perspective, of different substrate types (logs, snags and tops) of Norway Spruce, Picea abies, and if the quality of spruce logs as saproxylic habitats can be improved by simple log treatments (scorching and shading). We collected 9982 individuals representing 262 saproxylic beetle species in window traps. Both substrate type and, to a lesser extent, log treatment had a significant effect on the abundance and species richness of saproxylic beetles attracted to the different dead wood substrates. However, more importantly, the composition of the beetle assemblages differed significantly between both substrates and log treatments. Snags, logs and tops all attracted significantly different beetle assemblages and scorched logs differed from untreated control logs. Sixteen red listed species were trapped, with the highest number (11 species) being found on scorched logs. We found strong evidence that some species preferred a specific substrate type, mainly logs, in some cases treated logs (scorched or shaded), but not snags, the substrate commonly provided for conservation purposes on e.g. clear-cuts. This stresses the importance of conducting forestry in such a way that a multitude of both forest habitats and dead wood substrates are available continuously in the forest landscape to maintain biodiversity.     

中国经济林生态系统服务价值评估

基于中国经济林生态系统的长期、连续定位观测,采用第6次全国森林资源清查数据和国内外权威部门公布的价格参数数据,利用市场价值法、费用代替法、替代工程法等方法定量评价了2003年我国不同省份经济林生态系统的服务价值.结果表明：2003年,我国经济林生态系统服务总价值为11763.39×10⁸元,经济林产品总价值占总生态价值的19.93%,经济林除为社会提供直接产品外,还具有巨大的生态经济价值;各项功能的价值量依次为涵养水源＞固碳制氧＞生物多样性保护＞保育土壤＞净化环境＞营养积累;我国各省区经济林生态系统服务价值的空间格局与水热条件和生物多样性的分布具有趋同性.了解各省区经济林生态系统服务价值的差异,对改变目前我国经济林生产布局的不合理与经营上的弊端以及引导经济林向优质、高效、现代化方向健康发展具有重要意义.     

森林溪流倒木生态学研究进展

溪流倒木是指在河流中长度大于1 m、直径大于10 cm的死木。溪流倒木在森林河流中(特别是较小的河流中)是一个常见且重要的结构成分。该文综述了近30年溪流倒木的研究成果(主要来自北美),总结溪流倒木在河流形态、碳循环、泥沙与养分拦截、水生生境的形成、水生生物多样性等方面的生态功能,倒木的时间动态性与空间变异性,以及干扰(包括自然干扰与人为干扰)与倒木存留量及分布的关系。此外,该文也探讨了溪流倒木的生态管理模式及未来研究方向。大量的研究证明,溪流倒木对森林水生生态系统具有重要的生态功能,但它的存留量、分布以及它的生态意义因所研究的森林生态系统、河流大小不同而异。随着河流宽度的增加, 倒木的存留量及它对河流的影响减少,并且倒木的分布以单个为主变为聚集体为主。单个倒木的直径则随河流宽度增加而增大。倒木也呈现十分明显的时间动态性,而这种动态往往是由大规模毁灭性的森林干扰(火、风倒等)所驱动的。研究倒木的时空变异性及自然干扰与人为干扰对倒木的不同影响对于保持倒木的生态功能是十分必要的。该文还对中国开展溪流倒木的生态研究提出一些建议。     

江西省森林碳蓄积过程及碳源/汇的时空格局

森林碳蓄积是研究森林与大气碳交换以及估算森林吸收或排放含碳气体的关键参数,不同年龄森林的碳源/汇功能差异则体现出森林生态系统碳蓄积过程的时间特征。以森林资源清查的样方数据作为数据源,通过刻画主要树种的林分蓄积生长曲线、林龄与净初级生产力(NPP)之间的关系,驱动区域碳收支模型(InTEC)模拟江西省1950—2008年的森林碳蓄积过程,了解山江湖工程实施以来的森林碳源/汇状况。结果表明,20世纪80年代以前,江西省森林年平均NPP波动于450—813 gCm-2a-1之间,年净增生物量碳26.55—36.23 TgC/a,年净增木质林产品碳0.01—0.3 TgC/a;80年代初,NPP和年净增生物量碳分别降至307.39 gC m-2a-1和17.31 TgC/a,而年净增木质林产品碳却高达0.6 TgC/a,说明森林被大量砍伐进入林产品碳库;1985年山江湖工程实施后,大面积造林使得年净增碳蓄积呈现急剧上升趋势,生物量和木质林产品碳蓄积分别上升至目前的42.37 TgC/a和0.79 TgC/a,而平均NPP值增加缓慢、碳汇功能降低,说明林分质量有待提高;90年代后碳汇功能开始稳步增强,说明造林面积的迅速增加是引起江西省森林碳增汇的主要驱动因素,但未来森林增汇潜力应源于森林生长和有效的经营管理。     

Economic Analysis of a Pine Plantation Receiving Repeated Applications of Biosolids

Treated biosolids have been applied to 750-ha of a Pinus radiata forest plantation on Rabbit Island near Nelson City in New Zealand since 1996. A long-term research trial was established in 1997 to investigate the effects of the biosolids applications on the receiving environment and tree growth. An analysis of the likely economic impact of biosolids application shows that biosolids application has been beneficial. Stem volume of the high treatment (biosolids applied at 600 kg N ha^-1 every three years) was 36% greater than the control treatment (no biosolids applied), and stem volume of the standard treatment (300 kg N ha^-1) was 27% greater than the control treatment at age 18 years of age. Biosolids treatments have effectively transformed a low productivity forest site to a medium productivity site. Although this increased productivity has been accompanied by some negative influences on wood quality attributes with reduced wood stiffness, wood density, and larger branches, an economic analysis shows that the increased stem volume and greater average log diameter in the biosolids treatments outweighs these negative effects. The high and standard biosolids treatments are predicted to increase the net stumpage value of logs by 24% and 14% respectively at harvesting, providing a large positive impact on the forest owner’s economic return.     

中国土壤和植物养分管理现状与改进策略

针对当前我国农业生产面临增肥不增产、土壤养分过量累积、化肥施用过量和养分利用效率下降等重大问题,本文综述了中国土壤养分与植物营养状况的历史演变和研究进展,提出中国植物营养科学研究应在跟踪国际科学前沿的同时,紧密结合中国农业生产实际,通过大幅度提高养分效率和作物产量为农业可持续发展做出应有的贡献。