Improving maize production through nitrogen supply from ten rarely-used organic resources in Ghana

Where there is limited availability of conventional fertilizers, the use of organic materials is considered a viable alternative to increase the productive capacity of soils. Many potential plant residues remain underutilized due to limited research on their use as a nutrient source. In this study, the nitrogen supplying capabilities of ten rarely-used leaf biomass sources (Acacia auriculiformis, Baphia nitida, Albizia zygia, Azadirachta indica, Senna siamea, Senna spectabilis, Tithonia diversifolia, Gliricidia sepium, Leucaena leucocephala and Zea mays) were tested based on their nutrient content, N mineralization patterns and effect on maize yield (in comparison with inorganic fertilizer). N mineralization was studied in the laboratory using an incubation experiment. Field trials were also established using a randomized complete block design. Plant residues were applied at 5 t dry matter ha^?1 a week before planting maize while fertilizer was split-applied at 90 kg N ha^?1 on designated plots. From the results on plant residue chemistry, most of the plant residues recorded relatively high N concentration (≥24.9 g kg^?1) and low C/N ratio (≤20.1) although neither N content nor C/N ratio significantly (p > 0.05) affected their N mineralization patterns. Leaf biomass application of B. nitida, A. auriculiformis, A. zygia and maize stover resulted in an initial net N immobilization that lasted for 14 days. Application of all plant materials significantly increased the biological yield and N uptake of maize with G. sepium and T. diversifolia producing the greatest impact especially in the major rainy season. Relative to the control, total grain yield after four cropping seasons was comparable between inorganic fertilizer (9.2 t ha^?1), G. sepium (8.8 t ha^?1) and T. diversifolia (9.4 t ha^?1) treatments. The results on maize biological yield were significantly correlated with the effects of the treatments on N uptake. The findings suggest that in locations where inorganic fertilizers are limited, leaf biomass from G. sepium and T. diversifolia could offer the most suitable option in comparison with the other species used in this study.     

The science/policy interface in logic-based evaluation of forest ecosystem sustainability

Numerous efforts around the world are underway to apply the Montreal criteria and indicators to assess the sustainability of temperate and boreal forests. In this paper, we describe a logic-based system for evaluating the sustainability of forests at regional and national levels. We believe that such a system can make evaluation of sustainability more consistent and transparent. This effort also makes two points abundantly clear: (1) a systematic way to organize expert judgment about ecological, economic, social and institutional relationships (here, using ‘fuzzy logic’) is crucial to building such a system and (2) that the structure of this logic-based system reflects a policy framework and a series of decisions about values and what is meant by ‘sustainability’.     

我国退耕还林政策实施效果与可持续性研究

我国的退耕还林工程是林业六大工程之一,也是我国西部大开发的重要内容.退耕还林工程实施效果如何以及能否持续关系到中西部乃至全国的社会、生态、经济可持续发展.现选择贵州省黎平县作为案例对我国退耕还林政策实施效果与可持续性进行研究.通过第一手资料得出结论并提出该政策如何实现持续或顺利转换的建议.     

The influence of regulatory forest policy tools on biodiversity measures for forests in Ukraine

The transition from a state-oriented forest economy to a market-oriented one requires a critical analysis of the set of tools designed to implement state forest policies. One of the important goals of Ukrainian forest policy is conservation of the biodiversity of forest ecosystems. This paper analyzes the influence of two of the regulatory forest policy instruments (zoning and prohibition of final harvesting) on the diversity of woody vegetation using Tobit regression. Data on the forest resources of the Sumy administrative province in Ukraine are used for the analysis. Additionally, we look at how diversity of woody vegetation is affected by the form of forest tenure.     

The influence of regulatory forest policy tools on biodiversity measures for forests in Ukraine

The transition from a state-oriented forest economy to a market-oriented one requires a critical analysis of the set of tools designed to implement state forest policies. One of the important goals of Ukrainian forest policy is conservation of the biodiversity of forest ecosystems. This paper analyzes the influence of two of the regulatory forest policy instruments (zoning and prohibition of final harvesting) on the diversity of woody vegetation using Tobit regression. Data on the forest resources of the Sumy administrative province in Ukraine are used for the analysis. Additionally, we look at how diversity of woody vegetation is affected by the form of forest tenure.     

Improving the flow of scientific information across the interface of forest science and policy

The ever-expanding knowledge base of forest science is a challenge for scientists, the public and decision-makers to incorporate into forest policy and management. Scientific assessments have been used as a process to synthesize information on a variety of resource issues, including climatic change. As a process of communication, three attributes of assessments, assessment capacity, stakeholder participation, and articulation of uncertainty, can strongly influence the ability of the assessments to communicate scientific information. The institutional structure of the USDA Forest Service to conduct resource assessments has allowed a sustained effort to conduct periodic synthesis of scientific information and to address new policy issues, such as climate change. The US National Assessment on Climate Variability and Change engaged diverse stakeholders, such as public and private decision-makers, resource and environmental managers, the general public and scientific experts in a broad national and regional dialogue about changes in climate, their impacts, and what can be done to adapt to an uncertain and continuously changing climate. Both the National Assessment and the Third Assessment Report of the International Panel on Climate Change incorporated a language of uncertainty to describe consensus of the scientific community on the report's conclusions. These attributes are important elements of improving the flow of information across the science–policy interface.     

关于加强营造林工程管理全面提高工程建设质量的思考

国家实施生态环境保护和建设“林业六大工程”，给贵州省林业生态环境保护和建设带来了千载难逢的历史机遇。由于历史原因，贵州省的林业管理水平较低，科技含量不高，监督体系不健全等等，也严重影响了营造林工程的建设质量。因此，我们必须紧紧抓住“林业六大工程”的实施，严格按照“严管林，慎用钱，质为先”的要求；以林业生态建设工程为切入点，强化工程管理，做到“六个突破”，实现“六个转变”，才能全面提高营造林工程的建设质量。     

森林资源保护与粮食供给安全关系分析

粮食是极其重要的生活必需品。粮食又是一种特殊的商品,需求弹性较小,供给受自然过程的制约,其供求变化容易引起粮食市场的波动,影响宏观经济和社会稳定大局。那么,森林资源保护与粮食供给安全之间有着怎样的关系呢?且看相关研究报告:     

Rethinking recent changes of forest regimes in Europe through property-rights theory and policy analysis

This article studies recent changes in forest regimes in Europe from an analytical perspective, combining both property-rights theory and policy analysis. Important elements of the institutional framework for forests can be identified through the application of theories from institutional economics (property and use rights) and public policy analysis. Different examples of important changes in the institutional framework in European countries illustrate which components were most likely to change in recent years: the order frame of property and use rights in Central and Eastern Europe, due to the breakdown of the socialist systems; the implicit use rights for the public due to growing needs in leisure activities and nature protection; and the implementation arrangement, where the state gradually withdraws from forest management activities. A first analysis of the triggers and dynamics of the changes shows that slow and incremental changes in public policies are much more likely to occur than any reform of the property rights or forest tenures. In order to explain the changing institutional framework, it is necessary to take into account not only the contingent external triggers, but also the logic of learning processes and the actor networks in place.     

菲律宾竹藤生产趋势及其对政策和森林保护的影响

本研究梳理了菲律宾竹藤生产的官方数据,并阐述了其对竹藤资源开发和利用方面的相关政策法规的影响。对环境和自然资源部林业管理局于1997~2006年发布的年报统计中的数据、许可证和认可合同及林业收费进行了核对和分析。竹子生产量在2000年时最高,但从总体而言,除了近几年有小幅度恢复,产量呈下降趋势。在竹子出产大省中,森林不是主要用地。藤秆主要产自有相对大面积森林的省份。13地区是菲律宾的主要原木生产地区,同时也藤秆的主要供应地,其藤产量与木材产量齐头并进。该地区的森林资源非常紧张,仅有12.4%的森林是郁闭林,而在其它地区,35.7%的森林是郁闭林。最后,针对竹藤信息政策的监控、记录和报道政策,允许采伐量的评估,发展竹藤人工林的激励措施也提出了建议。     

Farm-forestry in the Peruvian Amazon and the feasibility of its regulation through forest policy reform

In 2015 the Peruvian government launched a new set of regulations associated with the forest law aimed to increase competiveness of the timber sector, ensure the conservation and sustainable production of timber on public and private forestlands, and improve rural livelihoods. Small-scale timber producers have been marginalized in the sector in the past, and the new regulations claim to provide pathways to formalization for these actors. We draw on policy analysis and field research in the central Amazon region of Peru using mixed methods to characterize smallholder on-farm timber production and evaluate the feasibility of the new regulatory mechanisms for formalizing small-scale timber producers. Through examining a case study on the production and sale of the fast-growing pioneer timber species Guazuma crinita, locally known as bolaina, we found a diversity of management practices, with the strongest reliance on natural regeneration in agricultural fallows, an informal supply chain, and no case of formal documentation at time of sale. We assessed that none of the new regulatory mechanisms will accommodate the sale of timber produced in agricultural fallow stands. We recommend the inclusion of fallow timber in the new forest plantation registry, which could result in the formalization of the supply chain and create an incentive to increase production by small-scale producers.     

论人工林对解决木材供需及环境的影响

本文结合世界人工林发展的趋势，阐述了发展人工林对缓解林产品需求及环境保护的重要性，论述发展人工林带来的经济、社会效益。     

Improving the establishment submodel of a forest patch model to assess the long-term protective effect of mountain forests

Simulation models such as forest patch models can be used to forecast the development of forest structural attributes over time. However, predictions of such models with respect to the impact of forest dynamics on the long-term protective effect of mountain forests may be of limited accuracy where tree regeneration is simulated with little detail. For this reason, we improved the establishment submodel of the ForClim forest patch model by implementing a more detailed representation of tree regeneration. Our refined submodel included canopy shading and ungulate browsing, two important constraints to sapling growth in mountain forests. To compare the old and the new establishment submodel of ForClim, we simulated the successional dynamics of the Stotzigwald protection forest in the Swiss Alps over a 60-year period. This forest provides protection for an important traffic route, but currently contains an alarmingly low density of tree regeneration. The comparison yielded a significantly longer regeneration period for the new model version, bringing the simulations into closer agreement with the known slow stand dynamics of mountain forests. In addition, the new model version was applied to forecast the future ability of the Stotzigwald forest to buffer the valley below from rockfall disturbance. Two scenarios were simulated: (1) canopy shading but no browsing impact, and (2) canopy shading and high browsing impact. The simulated stand structures were then compared to stand structure targets for rockfall protection, in order to assess their long-term protective effects. Under both scenarios, the initial sparse level of tree regeneration affected the long-term protective effect of the forest, which considerably declined during the first 40 years. In the complete absence of browsing, the density of small trees increased slightly after 60 years, raising hope for an eventual recovery of the protective effect. In the scenario that included browsing, however, the density of small trees remained at very low levels. With our improved establishment submodel, we provide an enhanced tool for studying the impacts of structural dynamics on the long-term protective effect of mountain forests. For certain purposes, it is important that predictive models of forest dynamics adequately represent critical processes for tree regeneration, such as sapling responses to low light levels and high browsing pressure.     

政策性森林保险的机遇与对策

本文阐述了启动政策性森林保险给森林资源培育业、集体林业和森林生产经营者以及相关保险业带来的保障性、发展性机会,系统分析了实施政策性森林保险可能遇到的来自需求愿望、承受能力、技术实力、制度保障等方面的制约因素,提出了推动政策性森林保险深入实施的八项对策措施:加大政府引导扶持力度;加大政策导向宣传力度;完善相关政策法规体系;建立有效组织体系模式;优化森林保险业务机制;建立协同配合工作机制;建立森林保险中介机构;建立森林风险分散机制。     

Cultural entrenchment: Explaining gaps between ecosystem-based management policy and practice in the forests of Newfoundland

Forests in North America have been managed, or unmanaged, under a number of different policy regimes, most recently ecosystem-based management (EBM), which has emerged in response to perceived widespread ecological degradation. But as policy regimes shift, links between stated objectives and the tools or mechanisms to achieve those objectives need to be forged. This case study of forestry on the island of Newfoundland provides an illustration of the gaps between EBM policy and practice, and insights into why EBM can be difficult to implement. Though the case of Newfoundland is unusual because of its isolation, narrow set of economic options, and weak ENGO sector, its adherence to a traditional timber regime offers lessons for the ways that policies move from agenda setting to implementation. In this case, the role of cultural entrenchment—a commitment to timber-based management and to a provincial model of economic support for large-scale industry—created a negative feedback loop that undermined new policy objectives. But a window of opportunity has emerged as a result of pulp and paper industry decline, and so overcoming cultural entrenchment and building a new forest management regime centered on EBM is possible through clearly articulated policy mechanisms and the integration of new forms of expertise.     

Long-term base cation mass balances for Swedish forests and the concept of sustainability

Data from the Swedish Forest Inventory was used to calculate mass balances for base cations Ca, Mg and K for Swedish forests. Using lysimeter and forest survey soil analyses to estimate present base cation leaching from the root zone reveals that weathering plus base cation deposition is not sufficient to support both, the present base cation leaching rate and the present rate of uptake caused by stem growth. Calculations suggest that 96% of the productive forested area may have higher rates of removal than supply for one or more base cation. Under a best-case scenario, assuming less pollution, the present growth rate and 100% efficiency in uptake of available nutrients, the area with more removal than supply would still be at least 30% of the total area. Forest soils are being depleted at a rate where the exchangeable reservoirs have high risk of being severely depleted in the next few decades in central and southern Sweden. During 1983–1985 the depletion rate is calculated to be, on the average, 0.33 keq ha⁻¹ year⁻¹. The weathering rate and present base cation deposition can sustain growth at a level where (80–85)×10⁶m³ stemwood year⁻¹ can be harvested. Any harvested growth beyond this volume must be sustained by artificial means.

For whole-tree harvesting without base cation return, the calculations indicate that it would significantly increase the base saturation depletion rate to an average of 0.62 keq ha⁻¹ year⁻¹, and risk depletion of the soil in less than one-to-two rotation periods almost anywhere in Sweden.

The calculations stress the importance that sustainable forest management must include the management of nutrient fluxes and reservoirs.     

Role of homestead forests in household economy and factors affecting forest production: a case study in southwest Bangladesh

Empirical information regarding the role of homestead forests in household economy is essential in understanding the importance of these resources. Identification of the factors that affect homestead forest production and understanding forest owners' attitudes toward key forest management issues have great significance in making appropriate policy responses to manage these resources on a sustainable basis. In Bangladesh, homestead forests are claimed to play an important economic role in rural livelihoods, but no reliable quantitative information exists. This study was undertaken to investigate the role of homestead forests in the household economy, examine if forest production and income vary across landholding size classes, to explore the relationships of homestead forest production with species richness, education level, and household size, and to assess the attitude of homestead forest owners toward key forest management issues. Results show that homestead forests contribute 15.9% of the household income and generate 51.4 man-days of employment per household per year. Production of homestead forests significantly varies across landholding size classes. It was observed that forest production depends significantly on species richness of homestead forests and the education level of forest owners. However, no such relationship was found between forest production and household size. The study revealed that farming families depend more on forest income than nonfarming families. Attitudes of forest owners toward key forest management issues differ significantly across landholding size classes. For example, although the majority of the forest owners prefer fruit species to timber species, the percentage of respondents decreased as the landholding size class increased, while the opposite trend was observed for timber species. The findings of this study suggest that diversification of forests and extension of education amongst forest owners would improve forest production. Furthermore, forest policy should address the concerns of the forest owners in different landholding classes and focus on their specific requirements to enhance sustainable forest management.     

A model of carbon storage in forests and forest products

This paper discusses the general formulation of a model that describes carbon storage in a forest and its timber products as a function of the forest growth curve, the rotation period and the carbon retention curves for the timber products. After a number of rotations, the rotation-averaged quantity of stored carbon approaches an asymptotic value. It is shown that, when forests are managed for maximum sustained yield of biomass, the contribution to asymptotic carbon storage from timber products is about 2.5D/T* times the contribution from living trees, where D is the characteristic decay time for reconversion of timber products to carbon dioxide, and T* is the normal rotation period for maximum sustained yield. For a given value of D/T*, carbon storage can be optimized if the policy of maximizing sustained yield is relaxed. For D/T* < 1, as the rotation period is increased indefinitely, the asymptotic level of carbon storage increases monotonically toward the value of the carbon content of living trees at maturity, g(f). For D/T* > 1, there is a finite, optimal rotation period, T(o), greater than T*, for which asymptotic carbon storage is greater than g(f). As D/T* tends to large values, however, T(o) tends to T*, so that, in this limit, management for maximum sustained yield also ensures maximum carbon storage. From initial planting, the time taken to reach asymptotic carbon storage decreases as the normal rotation period, T*, decreases, but increases almost linearly with increasing decay time of timber products, D. This result qualifies the short-term value of any particular planting strategy.     

Chaos theory and assessment of forest stakeholder attitudes towards Australian forest policy

The Regional Forest Agreement process has dominated Australian forest policy for the past decade. The RFA process set in place a mechanism by which benchmark conservation values were established for forest ecosystems, whilst addressing the needs of the timber industry. The outcomes of a number of RFA's have been fraught with controversy. Key stakeholder groups have shown disagreement with processes and outcomes of methods employed by government both in establishing conservation reserves and areas allocated to timber harvesting. This research uses non-linear techniques to examine the dynamical behavior in stakeholder responses and to identify patterns of behavior that may lead to prediction of stakeholder responses. The method developed in this research provides a bridge between social sciences and Chaos theory.¹