Evaluating the joint efficiency of German trade forecasts - a nonparametric multivariate approach

ABSTRACT

I analyse the joint efficiency of export and import forecasts by leading economic research institutes for the years 1970 to 2017 for Germany in a multivariate setting. To this end, I compute, in a first step, multivariate random forests in order to model links between forecast errors and a forecaster’s information set, consisting of several trade and other macroeconomic predictor variables. I use the Mahalanobis distance as performance criterion and, in a second step, permutation tests to check whether the Mahalanobis distance between the predicted forecast errors for the trade forecasts and actual forecast errors is significantly smaller than under the null hypothesis of forecast efficiency. I find evidence for joint forecast inefficiency for two forecasters, however, for one forecaster I cannot reject joint forecast efficiency. For the other forecasters, joint forecast efficiency depends on the examined forecast horizon. I find evidence that real macroeconomic variables as opposed to trade variables are inefficiently included in the analysed trade forecasts. Finally, I compile a joint efficiency ranking of the forecasters.     

城市生态系统中的森林研究

随着城市化水平的提高，城市的环境问题越来越突出，城市森林作为城市中重要的生命支持系统，对于维持城市生态系统平衡起着核心的作用，本文介绍了城市森林的概念和它的研究范畴，并着重分析了城市森林的综合效益，最后指出发展城市森林是人类自身发展的必然需要。     

浅析攀枝花市陡坡生态退耕模式

本文通过分析攀枝花市陡坡耕地的立地条件及其分布特点，因地制宜地建立了攀枝花市陡坡耕地的退耕还林与生态设计模式，提出了退耕还林措施，并从区域经济发展与环境生态建设相协调的角度，提出了攀枝花市退耕还林后社会、经济、环境的发展建议。     

农户参与下的退耕还林(草)效益预测研究——以甘肃定西县花岔流域为例

参与性农村评估(PRA.,Participatoryruralappraisal),是一种向研究区内群众学习,并同群众一道调查、分析和评估研究区发展所面临的挑战和机遇,并在享有完全信息的条件下,制订符合实际的相关的发展和研究计划的一种方法。借助这种手段,我们分析研究了花岔流域在现有条件及环境下退耕还林(草)对农民经济收入产生的影响。作为发展理论的一个重要组成部分,参与性评估理论在我国的研究还不多见,将其应用于西部开发的效益分析,对于我们正确进行政策分析、流域治理具有重要意义,本文在这方面提供了很好的范例。     

Economic Value of the Carbon Sink Services of Tropical Secondary Forests and Its Management Implications

This paper explores the economic feasibility of secondary forest regeneration and conservation as an alternative in the campaign addressing the problem of global warming. Detailed measurements of tropical secondary forests over time, in different ecological zones of Costa Rica, are used to evaluate carbon storage models. The paper addresses key issues in the international discussion about cross- and within-country compensation for carbon storage services and illustrates a method to compute/predict their economic value over time under a variety of scenarios. The procedure is applicable to other developing countries where secondary forest growth is increasingly important.     

Valuation and management of tropical forests

This paper develops a framework for the valuation and management of tropical forests that reflects their ecological and economic characteristics. The analysis demonstrates the importance of modeling the feasible use patterns and the information structure in tropical forest management decisions. The model predicts that cases exist where the foresighted management of forests leads to more preservation than the traditional expected value approach. An application in Thailand provides evidence that such cases occur in relevant ranges of benefit flows. The model focuses tropical forest management on assessments of sustainability and feasible sequences in light of uncertainty and information flows.     

云南"四林"旅游生命周期研究

本文把石林、元谋土林、陆良彩色沙林、元江彩色膏林并称为云南“四林”。云南四林均属林柱状旅游景观，但由于旅游开发的条件和因素不一，云南“四林”所处的旅游生命周期阶段不同。相关数据表明，石林属稳定发展阶段，沙林属快速成长阶段，土林属重振阶段，膏林属探查阶段。本文针对云南“四林”不同的发展阶段提出了相应的旅游开发措施。     

The contested environmental governance of Maori-owned native forests in South Island,Aotearoa/New Zealand

In this study we set out to critically examine the environmental governance of native forests owned and managed by the Maori in New Zealand, with a specific focus on ‘SILNA’ lands given to the South island Maori as compensation lands for lost ancestral tribal lands. We will interrogate reasons for different forestry pathways in terms of how the process of European colonisation unfolded politically and spatially, the response of the Maori SILNA forest owners to pressures linked to land allocation and land rights issues over time, and the repercussions of these responses for biodiversity preservation in indigenous forest management systems. In order to unravel the complex environmental governance processes at play in the New Zealand context, we will pay particular attention to ‘exogenous’ (i.e. propelling forces outside Maori communities) and ‘endogenous’ regulation mechanisms (i.e. regulation of native forest management within SILNA forest blocks). New Zealand is a particularly appropriate setting as Maori governance, forest management and land rights issues have come to the fore over the past decades. Our findings suggest that Maori SILNA forest owners have used the full spectrum of forest management pathways, ranging from outright clearfelling and associated biodiversity depletion to forest preservation. The study highlights the complex interplay between endogenous environmental governance processes (actor embeddedness with their land and the role played by trusts and committees in particular) and exogenous drivers, in particular through the influence of international logging companies, and the policy environment which has sent mixed, and at times confusing, messages to Maori SILNA native forest owners.     

深化集体林权制度改革新分析框架:集体林产权安全

产权经济学理论认为产权清晰或产权明确只是引导外部性内部化、激励与约束和减少不确定性功能的必要条件,而不是充分条件,产权功能的实现还有赖于产权的安全性。产权安全包括法律产权安全、事实产权安全和感知产权安全。集体林产权安全不足是由集体林产权赋权和产权制度实际运行导致。从行为经济学理论出发,集体林三个维度的产权安全性都会直接影响集体林经营主体经营行为,而经营主体因资源禀赋、认知能力、行为能力和风险偏好等因素具有异质性,其集体林经营行为必然存在差异性。因此,以“明晰产权、承包到户”为核心的集体林权制度改革未能取得预期的效果可以从集体林产权安全角度得到一定的理论解释。建立从集体林产权安全角度研究集体林经营主体经营行为的研究框架,具有科学价值和应用价值。     

The Economics of Forest Land Use in Temperate and Tropical Areas

This paper presents economic rules for harvest timing when timber and nontimber goods, services, and ecological functions are produced from forest stands. Forests include stands that are heterogeneous in age, land quality, and distance to market. Rules for allocating land between forest and nonforest use are developed. Key land use margins are identified that are important to land use allocation in temperate and tropical regions (e.g., between unmanaged forest, forest management, and forest conversion). Processes that can change key land use margins are discussed and used to organize recent empirical and theoretical studies of regions where forest land use is in transition, such as where forest land is being converted to alternative nonforest land uses.