Mathematical formulation and exact solution for landing location problem in tropical forest selective logging,a case study in Southeast Cameroon

In Central Africa, creating forest roads and skid trails is one of the most costly and environmentally damaging operations for the forest's ecosystem. An optimized road network is essential for reducing construction costs and improving the sustainable management of timber resources. The location of landings is vital in the development of a future forest road network. In this study, a binary integer programming model similar to the uncapacitated facility location problem is formulated to optimize the locations of the landings. The model is applied to selective logging in Central Africa and tested on an annual logging zone in Southeast Cameroon. The results are compared to that of manual road planning, the currently used method.     

Adapting the optimal selective-logging of Scots pine (Pinus sylvestris L.) stands in NE Spain to increasing CO2 concentrations

Predicted increases in CO₂ concentrations will affect forest ecosystems. In particular, they will impact tree growth, which in turn affects reproduction and mortality and consequently, forest planning. This study integrates different climate change scenarios of future biogeochemical processes and an economic model into a forest management model to determine the optimal selective-logging regime of Scots pine stands. It analyzes the economic implications of the management changes in comparison with the business as usual strategy. Adaption to new climatic conditions shows that it is optimal to increase the number of standing trees and to reduce the age of the logged trees. The results suggest that the failure to adapt the management regime has clear implications on the profitability of forests. Moreover, they show that higher mortality is likely to have a significant impact on the optimal forest management regime.     

森林采伐限额管理工作的问题与建议

森林采伐限额是采伐消耗森林、林木蓄积的最大限量。实行森林采伐限额管理是《森林法》确定的一项重要法律制度,是控制森林资源过量消耗的核心措施和加强森林可持续经营的关键手段。阐述了森林采伐限额的概念,分析了梨树县当前采伐制度存在的一些问题,提出了改进措施及具体做法,以寻求最佳的森林采伐管理制度,保护好国家珍贵而有限的森林资源,达到科学经营的目的。     

Editorial - Multiple-use forestry

The problem of multiple-use forestry arises because (1) a forest can be managed to provide a wide range of products and services, (2) the different uses are not perfectly compatible with each other, and (3) some products are not priced in markets and many of the services a forest provides have the characteristics of public goods. Examples of major forest products include, in addition to timber, edible berries, fungi, and hunting games. Forests also provide recreation opportunities and various environmental services (such as regulating local climate, reducing soil erosion, reducing pollutants in the atmosphere, regulating the global climate, providing habitats for wildlife, etc.). The outputs of nontimber goods in general depend on the quantity and structure of the forest, which can be changed by various forest management activities. However, a forest state most suitable for the production of one good is usually not optimal with respect to another good. Typically, there does not exist a set of management activities that simultaneously maximize the outputs of timber and all other goods.Another way to understand the conflicts between different uses is to view standing timber as an intermediate product of forestry investment, which is employed as an “input” for the production of timber products and nontimber goods. Thinking in this way, the conflicts arise partly because timber production and nontimber uses compete for the same input, and partly because of the differences in the “production technology” among different nontimber goods. A change in the standing timber may have positive impacts on some nontimber uses, but have negative effects on others. Because of the conflicts among different uses, it requires that both timber products and nontimber goods should be explicitly incorporated into forestry decision-making in order to achieve the greatest benefits to the forest owner and/or the public.Most of the economic analyses of multiple-use forestry decisions have explicitly or implicitly adopted the view that multiple-use should be achieved in individual stands. Each stand should be managed to produce an optimal mix of timber products and nontimber goods. Another view of multiple-use forestry is to manage each stand for a primary use, whereas multiple-use concerns are addressed by allocating different stands in a forest to different uses. A general argument in support of the primary-use view is that specialization makes for efficiency. The production of timber and nontimber goods is a joint process, however. Strictly speaking, one cannot separate timber production and the production of different nontimber goods. For example, managing a stand for timber production does not exclude the possibility of producing some nontimber goods in the stand. Since every stand usually produces more than one product, efficient multiple-use forestry requires that each stand should be managed for an optimal mix of timber and nontimber outputs. On the other hand, it may well be the case that the optimal multiple-use mix for a particular stand consists of a maximum output of one product. In this case the optimal multiple-use management decision would coincide with the optimal decision pertaining to a single use. In other words, it may be optimal to manage a particular stand for one primary use. Using the terminology of economics, primary-use may be efficient for stands in which the multiple-use production set is nonconvex. Recent research has explored several sources of nonconvexity in the multiple-use production set. However, there is no evidence supporting the argument that specialization is always more efficient than multiple-use management of individual stands. From an economics viewpoint, efficient primary-use is special cases of multiple-use stand management.A widely recognized limitation of multiple-use stand management is that, by considering each stand separately, one neglects the interdependence of nontimber benefits and ecological interactions among individual stands. The nontimber benefits of a stand depend on the output of nontimber goods from other stands. Likewise, the nontimber output from one stand affects the value of nontimber goods produced in the other stands. Ecological interactions among individual stands imply that the output of nontimber goods from two stands in a forest differs from the sum of the outputs from two isolated stands. These interdependence and interactions imply that the relationship between the nontimber benefits of a stand and the stand age (or standing timber stock) cannot be unambiguously determined - it depends on the flow of nontimber goods produced in the surrounding stands. Therefore, it is improper to determine optimal decisions for the individual stands independently. In stead, efficient multiple-use forestry decision should be analyzed by considering all the stands in a forest simultaneously.Another serious limitation of multiple-use stand management is that each stand is treated as a homogenous management unit to be managed according to a uniform management regime. One implicitly assumes that the boundaries of each stand is exogenously given and will remain unchanged over time. This assumption imposes a restriction on the multiple-use production set, thereby creates inefficiency. As an example, consider a large stand with a nonconvex production set. It may be possible to eliminate nonconvexity in the production set and push the production possibility frontier outwards by dividing the stand into several parts and managing each part for a primary-use. It may also be efficient to combine two adjacent stands into one to be managed following a uniform regime, because of the presences of fixed management costs, and/or because the relationship between some nontimber outputs and stand area is not linear.In contrast to income from timber production, nontimber goods produced at different time points are not perfect substitutes. The rate at which a forest owner is willing to substitute a nontimber good produced at one time point for that produced at another time point changes with the outputs of the nontimber good at the two time points. In general cases, the nontimber goods produced at one time point cannot be consumed at another time point, and the marginal utility of a nontimber good decreases when its output increases. This provides a motivation for reducing the variation in the output of nontimber goods over time. An effective approach to coordinating nontimber outputs over time is to apply different management regimes to different parts of a stand, or apply the same regime to adjacent stands, which would change the boundaries of the stands. Preserving the existing stand boundaries would limit the possibility of evening out the nontimber outputs over time, and thereby lead to intertemporal inefficiency in multiple-use management.In previous studies of multiple-use forestry decisions the nontimber outputs or benefits are usually modeled as functions of stand age or standing timber stock. Future flows of nontimber goods or benefits are incorporated into a stand/forest harvest decision model to explore the implications of nontimber uses for optimal harvest decisions. While stand age and standing timber stock may have significant impacts on nontimber outputs, other forest state variables, e. g. the spatial distribution of stands of different ages/species, may be of great importance to the production of nontimber goods. Recognition of such forest state variables could change the relationship between timber production and nontimber outputs and therefore change the optimal forest management decisions.In summary, multiple-use forestry is not simply an extension of timber management with additional flows of benefits to be considered when evaluating alternative management regimes. Recognition of multiple uses of a forest leads to two fundamental changes of the forestry decision problem. First, the optimal intertemporal consumption of forestry income is no longer separable from forest management decisions. In general, the optimal intertemporal consumption of forestry income depends on future flows of nontimber goods, implying that the consumption-saving decision should be made simultaneously with the decision on the production of timber and nontimber goods over time. Secondly, it is no longer appropriate to optimize the management regime for each stand separately. The nontimber outputs from a forest depend on the age distribution of individual stands, and on a wide range of other forest state variables such as the spatial distribution of stands of different ages and tree-species composition. Ecological interactions and interdependence among stands imply that management regimes for different stands should be optimized simultaneously. In addition to changing rotation ages and harvest levels, efficient multiple-use forestry requires optimizing the spatial allocation of harvests, redefining the boundaries of stands, coordinating the choices of tree species in regeneration of harvested area and so on.The lack of rigorous production functions for nontimber goods imposes a severe restriction on attempts to perform comprehensive economic analyses of multiple-use forestry decisions. This restriction in itself is no justification for ignoring many of the key aspects of multiple-use forestry problem and modeling the problem as one of determining the optimal rotation age or optimal harvest level. It requires that economic models of multiple-use forestry should be developed with special consideration of the vague and imprecise information regarding the relationships between nontimber outputs and forest state variables.Peichen GongDepartment of Forest EconomicsSE-90183 UmeåSweden     

资源综合开发利用与国有林业采育场可持续发展──三明市陈大国有林业采育场经营策略的调整

本文在分析三明市陈大国有林业采育场生产经营面临问题的基础上 ,提出国有林业采育场要实现可持续发展 ,必须立足采育场资源的综合开发利用 ,在林业分类经营的基础上 ,加大采育场的森林旅游资源开发和林地资源的开发利用 ,同时加强企业的管理。     

森林管护对森林生态安全的响应成效与影响路径分析

基于黑龙江省国有林区的数据,运用PSR模型构建了重点国有林区森林生态安全评价指标体系并运用熵权法进行权数确定,对2007—2016年的森林生态安全状况及森林管护对森林生态安全的响应成效进行分析。在此基础上,通过主成分分析及结构方程模型中的路径分析对森林生态压力、森林安全状态、森林管护响应及全面禁伐之间的综合影响路径进行分析。结果表明:在各项森林管护措施的积极作用下,森林管护对森林生态安全状况的响应成效十分显著。2007—2016年黑龙江省国有林区的森林生态安全状况处于持续上升的态势,黑龙江省国有林区的森林生态安全状况从最初的不安全状态,再到2010年以后持续稳定在一般安全状态,最后在2016年一跃达到了安全状态。森林生态压力对森林安全状态的提升具有负向影响。森林管护响应对森林安全状态的提升具有正向影响。全面禁伐作为国有林区改革进程中的一项重要森林管护政策对于减小森林生态压力提升森林安全状态发挥了重要的作用。因此,提出坚决走出"先污染后治理"的生态治理困境;积极践行"两山论"这一习近平生态文明建设思想的重要论断;全面加强天然林资源的保护及培育工作等建议。     

Carbon dioxide emissions from wood fuels in Sweden 1980–2100

It is often assumed that wood fuels are carbon neutral. This is approximately true in the very long run since the emissions from burning wood fuels are compensated by the uptake from new trees. But it is not true in the short- and the medium term due to a number of factors. This problem is analyzed in detail in this paper, where the net carbon (dioxide) effect of using wood residues in Sweden 1980–2100 is calculated. Two important implications of the program for using wood fuels are considered: (i) the decrease of carbon stored in logging residues due to a faster transformation to carbon dioxide and (ii) delayed growth of new forest generations when logging residues are removed from the forest and used as fuel. The effects of both these factors are calculated (and projected) for the period 1980–2100. The main result is that wood fuels (in the form of wood residues) emits about 60% of the carbon dioxide that would have been emitted if the corresponding amount of energy would, have been produced by oil. One policy implication of this is that emissions from wood fuels should not, as is now the practice, be ignored and by definition equaled to zero, in national and international statistics of green house gas emissions.     

Forest governance and economic values of forest ecosystem services in Vietnam

Forest ecosystems deliver valuable services to humanity. However, many forests are being degraded and their services have been undervalued. The main problem lies in the inadequate institutional arrangements for forest governance. This paper aims to assess the effects of alternative forest governance arrangements on the provision and economic values of forest ecosystem services (FES) in Vietnam. The study presents a framework for mapping land use and land cover (LULC) change stemming from actual and hypothetical changes in forest governance regimes, quantifies the resulting changes in the provision of FES, and estimates the associated economic values. In the context of the study site in the North Western uplands of Vietnam, we test three alternative forest governance scenarios: business as usual, with a dominant government role; a community-based governance regime; and a private, individual-based forestry governance regime. Scenarios are based quite closely on the way these regimes are (or might be expected to be) implemented in Vietnam. For each forest governance scenario, we map LULC changes based on land suitability analysis and transition likelihood for the period 2010 − 2020. The resulting maps are used as inputs into the InVEST (Integrated Valuation of Environmental Services and Tradeoffs) model, which is used to estimate the quantity of three specific FES: carbon storage/sequestration, sediment yield, and water yield. We apply economic valuation methods to value these services: the social cost of carbon is used to estimate the economic values of carbon storage/sequestration; the cost of removing sediment deposited in reservoirs is applied for valuing the reduction of sediment yield, and the residual value of water supply for hydropower generation is used for valuing water yield. The results show that forest governance regimes have a significant effect not only on forest LULC, but also on the quantity and values of FES derived from forests. The FES are differentially affected by alternative forest governance regimes: some FES increase in quantity and value under some governance regimes and decrease under others. Of the three forest governance regimes examined, there is no one regime that will always be ‘better’ than the others in terms of provisioning all considered FES. For the specific context of Vietnam, we find that the private forest governance scenario is inferior to the community-based governance scenario, as an alternative to the current state-based governance. Because our results pertain to the scenarios as constructed, rather than generally to broad categories of governance regimes, there remains the possibility that regimes can be constructed that outperform all of those examined here.     

The sustainability of timber production from Eastern Amazonian forests

Although the regulations are imperfectly enforced, logging firms in the Brazilian Amazon are subject to forest management regulations intended to reduce environmental damage and protect future forest productivity. Additionally, voluntary best practices firms adopt to achieve environmental performance that exceed regulatory requirements are largely limited to reduced impact logging (RIL) systems that reduce harvest damage relative to conventional logging systems used by a large majority of firms in the region. Existing regulations combined with best practices may not be adequate to ensure sustained yields. This inadequacy is an important issue as Brazil implements an ambitious program of forest concessions on public lands. We analyze the profitability and environmental outcomes of best logging practices and proposed sustainability requirements. We propose two operational definitions of sustainability (the first focusing on sustaining stand-level timber volumes and the other focusing on sustaining species-level volumes within the stand) based on sustaining timber inventories across cutting cycles rather than on sustaining overall harvest yields. RIL is shown to be profitable for loggers and increase the timber available for future harvests. While volume predicted to be available for the second and third harvests are significantly lower than the available timber in the unlogged forest, the second and third harvests are projected to be profitable and have the potential for sustainability despite high opportunity costs. However, as harvesting is repeated into the future, results show the composition of the harvest shifts from higher-value shade-tolerant and emergent species toward a greater reliance on longer-lived, lower-value pioneer species. This shift may create pressure to expand the forest base under management in order to continue to supply high-value species or increase the risk of timber trespass in conservation units and areas under community or indigenous management.     

创新机制 转变方式 努力开创森林保护和经营新局面

湖南省紧紧围绕国家林业局采伐管理改革具体部署:推进采伐分类管理,使采伐管理范围更加明确;编制森林经营方案,使限额管理更加科学;创新分配机制,使采伐指标分配更加公平;简化审批程序,使采伐指标申请更加便捷;加强监督管理,使采伐秩序更加规范。     

DO HIGH DISCOUNT RATES DESTROY TROPICAL FORESTS

The short-term viewpoint implicit in high discount rates seems to favour immediate forest exploitation rather than conservation for perpetual benefits. However, the value of logging revenues increases with a lower discount rate, because of the greater weighting given to investible funds. Thus, in several theoretical models, net present value of logging increases as discount rate is lowered. In practice, however, long-term costs of logging may also incur the weighting appropriate to investment funds; reinvestment of logging revenues may not actually take place; and lower discount rates may be appropriate for costs but not revenues. These circumstances favour conservation, the more so at lower discount rates.     

国有林区森林资源变化趋势及影响因素分析

通过二类资源清查数据,对东北国有林区三个主要地区的森林资源变化情况进行了分析。国有林区森林资源变化趋势存在地区性差异,内蒙古和吉林的森林资源优于黑龙江国有林区,全局性的森林资源危机并不存在。国有森工企业土地利用方式调整与天保工程实施等因素对国有森工企业走出资源危机有积极的影响。     

森林资源型产业商品性生产的政府规制模式研究

森林资源型商品性生产包括商品林生产经营、林下种养殖业和采集业、森林旅游业,这类产业主要是以商品性经营为主,是市场机制作用相对较强、政府作用相对较弱的领域。但同时,由于其生产过程中是以森林资源为依托,且具有生产过程的外部性,因此,必须对其进行合理的规制。主要对森林资源型产业商品性生产政府规制的目标、主体、模式及其运行进行了探究。     

林产品进口贸易与环境保护问题研究

在目前已有对森林资源环境效益评价基础上,通过探讨林产品进口贸易与环境保护的关系,考虑不同木质林产品生产加工过程中对环境的影响,根据中国进口林产品的进口来源,指出了中国林产品进口贸易的环境影响以及非法木材贸易对环境的破坏。结果表明:国际上对中国大量进口木材的指责缺乏依据;对世界和中国来说,共同开发森林资源,打击非法木材采伐与贸易,中国大力发展可替代产品,走林业可持续发展之路,是双赢的必然选择。     

Emergence and influence of a new policy regime: The case of forest carbon offsets in British Columbia

The most significant carbon mitigation policy currently targeting BC’s forests is the Forest Carbon Offsets Protocol (FCOP) that outlines the rules regulating forest carbon offsets. By applying the Policy Regime Framework to the FCOP, this paper addresses the following specific questions: what is the extent of the policy change brought by FCOP, and what are the main factors that influenced and shaped this policy change? The paper concludes that policy did change: an offset regime was established and FCOP was adopted to steer the development of forest carbon offsets. It is the executive branch of government, and especially Premier Gordon Campbell, that was most influential during problem definition and the decision making around forest carbon offset policy. In addition, environmentalists and First Nations, by advocating for a conservation economy, and the private sector, by lobbying the government to prioritize their economic interests, also influenced the policy making process. However, the actual magnitude of policy change that occurred with the emergence of the forest carbon policy regime is quite limited. Apart from a few conservation and improved forest management projects that mostly benefited First Nations, very few projects have been successfully implemented to date. This limited policy change was caused by various economic, social and political limitations. In particular, the shift in government in 2011 that led to the decision not to implement a cap and trade program significantly reduced marketing opportunities for BC-based forest offsets. In addition, the negative public opinion towards the credibility and effectiveness of forest carbon offsets, the low international price of carbon, the high transaction costs and the lack of financing options strongly restrained their development.     

浅析玛可河林业局森林管护模式

玛可河林区是我国长江流域大渡河源头面积最大、分布最集中、海拔最高的一片天然原始林区,曾为国家经济建设生产木材68万m3。1998年启动天然林资源保护工程,天然林采伐量调减为零,通过切实可行的森林管护,有效地促进了天然林资源保护和恢复,森林资源和生态环境状况得到了明显的改善,森林覆盖率由天保工程实施前52.6%增加到59.0%,活立木蓄积从361万m3提高到460万m3,取得了显著的生态效益、社会效益和经济效益。     

Correlates of forest-cover change in European Russia, 1989–2012

European Russia rapidly transitioned after the collapse of the Soviet Union from state socialism to a market economy. How did this political and economic transformation interact with ecological conditions to determine forest loss and gain? We explore this question with a study of European Russia in the two decades following the collapse of the Soviet Union. We identify three sets of potential determinants of forest-cover change—supply-side (environmental), demand-side (economic), and political/administrative factors. Using new satellite data for three distinct types of forest-cover change—logging, forest fires, and forest gain—we quantify the relative importance of these variables in province-level regression models during periods of a) state collapse (1990s), and b) state growth (2000s). The three sets of covariates jointly explain considerable variation in the outcomes we examine, with size of forest bureaucracy, autonomous status of the region, and prevalence of evergreen forests emerging as robust predictors of forest-cover change. Overall, economic and administrative variables are significantly associated with rates of logging and reforestation, while environmental variables have high explanatory power for patterns of forest fire loss.     

评价林业投资的实物期权方法

评价风险较高的林业投资,传统的净现值法(NPV)容易低估项目的价值,不能客观地对林业投资做出正确评价。林业项目的不确定性反映了林业投资具有一定的期权特性,因此本文基于实物期权的理论和方法,建立了林木采伐的实物期权决策模型,将林木收益问题当作一个实物期权问题处理,应用实物期权模型来决定林木最佳采伐时机。     

国际木材非法采伐与相关贸易问题研究

探讨了非法采伐的定义、现状,从生产国与市场的角度分析了非法采伐产生的原因,并分析了非法采伐产生的影响。介绍了国际上打击非法采伐与相关贸易的行动和协议,结合以中国为中心的林产品进出口贸易情况,分析中国林产品进口对非法采伐问题的影响。林产品生产国与消费国在非法采伐问题上应承担主要的责任,提出了解决非法采伐与相关贸易的措施。