Forest ecosystem recovery in the southeast US: soil ecology as an essential component of ecosystem management

The forestry industry in the southeastern United States relies upon soils that are highly eroded and depleted of their original organic matter and nutrient content. Pro-active land management can ensure continued and possibly increased production and revenue through the management and recovery of the soil resource. With an emphasis on loblolly pine (Pinus taeda L.) forests, this review integrates land-use history, pine ecology, silviculture, soil ecological research and the implications for forest management into a single discussion. Promoting soil recovery involves knowledge of ecosystem history and disturbance as well as nutrient cycling mechanisms, pools, fluxes and soil forming factors. Research on the rhizosphere is an area that is needed. Recovery of regional soils may confer benefits of drought and disease resistance. The goal of sustainable forestry is compatible with soil recovery; however, the technology and practices of modern forestry deserve thorough evaluation. Emphasis on the continued production of commodities, the agricultural model, is much different from managing for the functioning of healthy forest ecosystems. Many of the practices and outcomes of intensive forest management, including short rotations, harrowing, subsoiling, and burning or removal of logging slash, seem to be at odds with the goal of soil recovery. Best management practices that foster soil recovery include less intensive stand utilization and reduced soil disturbance. Stem-only harvest and longer rotations permit a recovery of soil biodiversity and an accrual of detritus and soil organic matter. Windrowing and similar techniques have dramatic and lasting effects on soil development. No-tillage agriculture as a model for pine plantations is discussed.     

人工林土壤碳库研究进展

在综合阐述人工林碳库动态研究对全球陆地生态系统碳收支和区域林业经济持续发展意义的基础上，对有关土壤碳库动态和稳定性的主要指标，如TOC(总有机碳)、DOC(可溶性有机碳)、MBC(微生物生物量碳)、POMC(颗粒有机物碳)和SR(土壤呼吸)等及其影响因子进行了重点评价，针对我国人工林经营和碳库研究现状，结合国际农林业土壤碳收支和动态研究趋势，认为我国主要人工林碳库研究的2个主要方向为：(1)土壤碳库物理化学稳定性指标与生物的交互作用；(2)土壤碳库动态与全球变化关系及其环境效应评价。     

甲壳素和壳聚糖的研究及其在农林业中的应用

本文扼要介绍了甲壳素和壳聚糖的性质、研究概况和主要用途,着重论述了甲壳素和壳聚糖在农业和林业中的应用情况,分析了甲壳素和壳聚糖在林业中的潜在应用前景,指出安全无毒且对环境无公害的天然高分子壳聚糖和甲壳素在林木种子处理、森林土壤改良、森林病虫害防治、水果保鲜和木材工业中均有很光明的应用前景。     

陕西土壤有机质与全氮量的关系

分析表明,陕西省9类主要农林土壤有机质与全氮量呈极显著正相关,两者间的回归方程及换算系数均可用于由有机质含量来较准确地估测全氮量。     

Agroforestry and its application in amelioration of saline soils in eastern China coastal region

Some environmental problems, especially soil salinity hinder the regional sustainable development of eastern China coastal region. Salinity mainly comes from tide weave, seawater flooding and seawater intrusion. Over exploitation of groundwater,which is the result of unfitful land use systems, leads to seawater intrusion and salt concentration increase. Agroforestry systems can enrich soil fertility and prevent soil salinization, furthermore help maintain biodiversity and enhance productivity. For the intergrated multiple ecosystems the most critical issue is to select optimum tree species and rationally arrange these plants. The basics of this multiple ecosystem is that different plants will occupy variable ecological niches within an area, both in space and in soil depth.Shelterbelts and trees intercropping with agricultural crops are major types of the multiple ecosystem. Shelterbelts can reduce wind speed and consequently lessen evaporation and erosion of the soil, increase pasture growth by up to 60% on exposed sites, increase crop yields by up to 25%. Besides intercropping with jujube, other agroforestry multiple ecosystem such as forestry plus agriculture,forestry plus agriculture plus fishery, and forestry plus animal husbandry are the most appropriate ways to utilise land resource in this region.     

Soils, Forests, and Pastures in South Wales

Marginal upland soils may be used for forestry or sheep grazing.In the State Forests of South Wales a study of selective plantingshows the greatest volume yield is generally obtained from Sitkaspruce (Picea sitchensis) planted in ridge-crest soils. Yieldsfrom Sitka spruce on ridge-flank soils are reduced by the presenceof Ericaceae on upper slopes and the dryness of the soils onlower slopes. Contrary to this trend, the nutritional valueof the pasture for sheep is lowest on ridge crests and increasesdownslope, being greatest on the Agrostis pastures of lowerslopes. Further, reclamation is most economically accomplishedon ridge flanks where they are not too steep. Although profitcomparisons are very difficult to make, ridge slopes might bemore usefully allocated to sheep grazing and ridge crests toSitka spruce forests. To be economically viable, a forest mustbe large, but within any new forestry acquisitions the largerareas occupied by slope soils might be reclaimed or utilizedas sheep pastures.     

人工林精准施肥研究进展

施肥是实现人工林速生丰产的重要手段,合理施肥可以维持土壤养分平衡,提高土壤质量,促进林木生长,同时减少环境负效应。人工林精准施肥是以农业精准施肥为基础形成的营林应用技术体系,主要包括林地管理单元精准划分、林地营养精准诊断、精准施肥及施肥效应精准检验。精准施肥技术在农业上取得了很大进展,但应用到人工林上还有很大的局限性。文中结合农林业施肥研究现状,分析实现人工林精准施肥所需解决的关键问题,提出人工林精准施肥的发展方向。     

农林高校实验室安全风险评估探索与实践——以北京林业大学为例

开展安全风险评估是管控实验室风险、提升安全管理水平的重要手段。农林高校的实验室具有鲜明的行业特色,需要根据其特点开展针对性的安全风险评估工作。文中分析农林高校实验室分类分级管理和项目风险评估的现状,以北京林业大学为例介绍其实验室安全风险评估的探索与实践:根据危险源类型将实验室分为化学类、生物类、机械电子类和其他类4个类型,根据风险评估结果将安全风险水平划分为4个级别,依托分类分级结果进行精细化管控,在科研项目申报和立项阶段开展项目安全风险评估与识别,对实验教学项目进行分类分级安全评估等,其经验可为农林高校实验室风险评估体系的构建提供借鉴。     

Agroforestry education and training programs: an overview

Agroforestry has been incorporated in education and training programs at an unprecedented level since 1982. A survey of educational institutions conducted by ICRAF in 1987 revealed that agroforestry is found as an option for specialization in undergraduate as well as in postgraduate M.Sc, diploma programs in forestry, agriculture, natural resources, and others. Courses and special seminars in agroforestry are organized in degree programs. Full undergraduate and postgraduate programs in agroforestry are being formulated and implementation started in quite a few universities, and many students are choosing agroforestry-oriented research projects for their dissertations. A good setting for higher degree training in agroforestry requires, however, staffing from combined faculties of at least agriculture, animal science and forestry; faculty commitment to a farming systems approach; and inter-departmental cooperation in teaching and research. It was difficult to asses whether these and other elements are present in existing programs where agroforestry has been incorporated. Emerging trends indicate that traditional forestry programs are broadening the scope of the discipline (from forests to integrated land-use systems) while agriculturists are recognizing that trees play important roles as soil improvers and protectors, fodder, food, fuel and other domestic and commercial purposes. New institutional structures are evolving to allow for educational programs with coursework and research projects spanning many disciplines. Nondegree training in agroforestry has seen an upsurge of activities equal, if not larger, to that in education. Attempts are being made by different institutions worldwide to inventory training opportunities; still the collection and dissemination of information is difficult. Efforts are needed at the international, regional, and national levels, to address training issues that if addressed collectively can improve the quality and effectiveness of human resource development efforts. ICRAF's approach to promote agroforestry research through education and training is an example of an action program currently under application.     

Forestry strategy and land use policy in areas with high population pressure

Premature felling and the encroachment of agriculture are the major threats to forestry on state-owned land in densely populated areas of Southeast Asia.In this article the potential for, and the constraints upon, converting forest land into agricultural land to reduce the pressure on the remaining forests of Southeast Asia are studied. It is concluded that in many countries the present areas officially designated as ‘forest’ largely reflects past decisions. Changes in the demand for products and technology, both in agriculture and forestry, have led to a shift in the relationship between land rent and use capacity. As a result, a larger area is today considered to be suitable for agriculture. Increasing the yield from land currently in agriculture can, however, be preferable to extending agriculture to marginally suitable land.As well as choosing between forestry and agriculture, land use policy must also determine the forestry strategy. Possible strategies for forestry on state-owned land include social, industrial or environmental forestry. The final choice must be based on adequate data. It is shown that in areas with high population pressure, predictions based on yield tables, determined in stands not disturbed by local people, result in the wrong decisions being made.It is also shown that the point of view on which a decision is based can influence the choice of such factors as tree species, rotation and initial tree-spacing. Objections related to conservation can hold up the conversion of forest land to agricultural land, as can objections questioning the feasibility of the conversion. On state-owned land conflicting interests and the long production period in forestry (which forces a long waiting period upon the farmer before he receives benefits and can cause legal difficulties) hamper the introduction of social forestry.Finally, the introduction of social forestry requires an ample study of socio-economic and cultural aspects of the local population. It is concluded that forest planning in areas, where social forestry could be developed, must include a study of state-owned and private land, as well as forest land and non-forest land.     

贵州林业土壤

本文介绍了贵州林业土壤的自然地理环境，主要成土过程，土壤分类，土壤地理分布规律，主要林业土壤的剖在形态，理化性质和宜林性状，林业土壤资源和主要造林树种及经济林的适生土壤。     

林业生态工程建设与黄河三角洲可持续发展

黄河三角洲具有很大的农业开发潜力,是国家重点农业综合开发区,由于黄河上中游森林植被减少,水资源浪费严重等原因,造成下游径流量减少和断流,加上海潮侵袭、土壤盐碱化、森林覆盖率低、海岸蚀退等环境因素的制约,严重影响该区域农业可持续发展。本文在系统分析黄河三角洲可持结发展存在问题以及林业在实现区域经济社会可持续发展中主要战略地位的基础上,提出该区域２１世纪林业生态工程建设的方向和任务。     

林草间作系统研究概况

林草间作经营在挖掘生物资源潜力、缓解农林争地、保护及修复生态系统、推进林农增产增收、石漠化及荒漠化综合治理等方面具有巨大优势。为达到土地及自然资源的最大化利用,节约林农生产经营成本,推进农、林、牧、副业的高效、和谐、健康发展,实现森林及草地生态系统生态、经济、社会效益的有机统一。文中阐述了在中国、亚洲、澳大利亚及新西兰、非洲、美洲、欧洲等地区林草间作的研究背景、内容、类型及特征,分析了林草间作对土壤性状、养分、含水量及固土保肥的作用,总结归纳林草间作对经济、生物多样性、微气候、林木及其产品的效益分析,提出林草间作未来深入研究探索的技术手段及方向,可为林草间作的应用推广及系统性、整体性和定量研究提供参考。     

关于加强林业科技推广能力建设的思考

根据福建林业科技推广工作改革与发展实际,分析了林业科技推广的作用及传统林业科技推广方式的局限性,阐述了加强林业科技推广能力建设的重要意义,提出了以提高林业科技成果转化能力、林业重点工程科技支撑能力、林业科技推广持续发展能力、林业科技服务“三农”能力和人才兴林能力等为目标的推广能力建设方略。     

Nitrogen-fixing legume tree species for the reclamation of severely degraded lands in Brazil

The main challenges faced in the reclamation of severely degraded lands are in the management of the systems and finding plant species that will grow under the harsh conditions common in degraded soils. This is especially important in extremely adverse situations found in some substrates from mining activities or soils that have lost their upper horizons. Under these conditions, recolonization of the area by native vegetation through natural succession processes may be extremely limited. Once the main physical and chemical factors restrictive to plant growth are corrected or attenuated, the introduction of leguminous trees able to form symbioses with nodulating N?-fixing bacteria and arbuscular mycorrhizal fungi constitutes an efficient strategy to accelerate soil reclamation and initiate natural succession. These symbioses give the legume species a superior capacity to grow quickly in poor substrates and to withstand the harsh conditions presented in degraded soils. In this article we describe several successful results in Brazil using N?-fixing legume tree species for reclamation of areas degraded by soil erosion, construction and mining activities, emphasizing the potential of the technique to recover soil organic matter levels and restore ecosystem biodiversity and other environmental functions.     

林业的目标、原则和发展道路

作者将林业分为采掘林业、集约林业和生态林业.认为采掘林业应当被抛弃。集约林业投资高,对地力要求严格,与农业争土地、水和能源以及生态上稳定性差,在我国的发展规模应受到限制。以充分利用自然力为特征的并能使林业的多重目标得以协调发展的生态林业应占主导地位。     

Farms, fires, and forestry: Disturbance legacies in the soils of the Northwest Wisconsin (USA) Sand Plain

We studied the long-term effects of disturbance within the Northwest Wisconsin (USA) Sand Plain (NWSP), an ecoregion that is characterized by very sandy soil and an active disturbance history that includes fire, agriculture and industrial forestry, largely clearcut logging of jack pine (Pinus banksiana) and aspen (Populus spp.). Open “barrens” communities on this landscape were formerly maintained by fire, and are a high conservation priority. Hill's Oak (Quercus ellipsoidalis) can also dominate forest canopies, while blueberry (Vaccinium angustifolium), and sweetfern (Comptonia peregrina) are common shrub species. We structured a field sampling design with a spatial-temporal database built from historic airphotos (1938 and 1997) and fire records to examine whether soil organic matter and nutrients vary with disturbance history in the nonforest habitats of the sand plain. We sampled soils along 83 transects, randomly stratified among five sampled classes: (1) nonforest-farming history; (2) nonforest-fire history; (3) nonforest-clearcut only history; (4) evergreen forest of jack pine and red pine (P. resinosa); and (5) deciduous forest of Hill's oak and aspen. Logging of the original forest took place in the late 1800s–early 1900s. The farms were abandoned between 1938 and 1960, and the most recent fire occurred in 1977. Thus, the duration of the agricultural legacy is approximately 45–65 years while observed fire effects have lasted for 26 years.We observed strong agricultural legacies, including high P and low OM, N and Ca. One possible explanation for the N legacy is that it is tied to soil OM accretion which may be driven by plant growth. We detected no difference in mean values for any of the soil properties between soils from nonforested areas within the Five-Mile fire and soils from nonforested areas with a clearcut-only history. We did observe a fire effect in high variance for soil P. This could have resulted from variations in fire severity and ash convection and deposition.Forest soils generally had lower pH than the nonforest soils, and the deciduous forest soils had the lowest pH and also very low Ca. We also observed high within-transect coefficient of variation for Ca in the forest soils.We conclude that agriculture is a qualitatively different disturbance-type than fire or clearcutting, that disturbance legacies tend to be most persistent with geologically stable elements, such as P, and that management and conservation planning within the NWSP would benefit from site-specific agricultural history, as well as attention to Ca.     

农林区系鸟类生态学研究进展

鸟类是农林生态系统中非常重要的一个组成部分,在一定程度上可以抑制农作物及林木病虫害的发生,对复合农林生态系统的健康发展具有十分显著的作用,因此引起不少鸟类学家对农林区系鸟类生态学的关注。本文对鸟类生态学及其研究内容进行了阐述,并重点介绍了国内外对农林区系鸟类生态学的研究内容、方法和成果,在此基础上对研究方向做了展望。     

沙质土壤植物性节水保肥材料研究与应用

干旱区沙质土壤缺乏矿物质和有机胶体、漏水漏肥,是沙区植被修复和生态林业建设的主要障碍,与此同时随着生态建设和林草业的发展产生了大量的植物性有机废弃物。因此,回收利用林业剩余物,研发植物性节水保肥材料,改良干旱区风沙土,具有恢复退化土地和回收有机物料的双重意义。文中概述了植物性节水保肥材料在荒漠化防治特别是沙漠林业开发中的重要性,综述了植物性节水保肥材料种类和发展史,对比国内外研究和应用有机物料改良沙质土壤的趋势和特点,从林业剩余物利用和荒漠化防治等领域提出了研发建议。