Causes of deforestation in southwestern Madagascar: what do we know?

Causes of deforestation are discussed in the case of southwestern Madagascar. The article has two objectives. First, the idea is to discuss the usual linear regression approach to determine causes of deforestation. Secondly, the intention is to determine the causes of deforestation in our case study. Distinction is made between direct causes (agriculture, wood collection, and pasture land) and indirect causes (migration, export prices, property rights, and government policies). In outlining the strategies of the peasants, the article ends up with an estimation of the value of agricultural land vs. an estimation of benefits derived from utilisation of non-timber forest products from primary forest or scrub (value of medical plants and roots used as staple food).     

Effects of roads,topography, and land use on forest cover dynamics in the Brazilian Atlantic Forest

Roads and topography can determine patterns of land use and distribution of forest cover, particularly in tropical regions. We evaluated how road density, land use, and topography affected forest fragmentation, deforestation and forest regrowth in a Brazilian Atlantic Forest region near the city of São Paulo. We mapped roads and land use/land cover for three years (1962, 1981 and 2000) from historical aerial photographs, and summarized the distribution of roads, land use/land cover and topography within a grid of 94 non-overlapping 100 ha squares. We used generalized least squares regression models for data analysis. Our models showed that forest fragmentation and deforestation depended on topography, land use and road density, whereas forest regrowth depended primarily on land use. However, the relationships between these variables and forest dynamics changed in the two studied periods; land use and slope were the strongest predictors from 1962 to 1981, and past (1962) road density and land use were the strongest predictors for the following period (1981–2000). Roads had the strongest relationship with deforestation and forest fragmentation when the expansions of agriculture and buildings were limited to already deforested areas, and when there was a rapid expansion of development, under influence of São Paulo city. Furthermore, the past (1962) road network was more important than the recent road network (1981) when explaining forest dynamics between 1981 and 2000, suggesting a long-term effect of roads. Roads are permanent scars on the landscape and facilitate deforestation and forest fragmentation due to increased accessibility and land valorization, which control land-use and land-cover dynamics. Topography directly affected deforestation, agriculture and road expansion, mainly between 1962 and 1981. Forest are thus in peril where there are more roads, and long-term conservation strategies should consider ways to mitigate roads as permanent landscape features and drivers facilitators of deforestation and forest fragmentation.     

Spatial Modeling of Tropical Deforestation Using Socioeconomic and Biophysical Data

Tropical forests are disappearing at an alarming rate. In Central America, a hectare of forest is cleared for agriculture every 5 min. This study was conducted in a forested 4,000 ha watershed of central Honduras to find deforestation causes based on socio-economic characteristics of population. First, a multitemporal analysis of Landsat TM imagery was conducted to determine deforestation rates and agricultural–forest boundaries. A GIS buffer procedure allowed determining which households were at the deforestation front and which households were located at the rest of the area (control). GIS techniques were used to extract biophysical information such as slope, elevation, land cover, temperature, precipitation, etc. Then, we set up a data base with more than 50 socioeconomic variables (level of education, income, children per family, major economic activity, use of conservation practices, etc.). Around 500 households, distributed all over the watershed, were visited, interviewed and GPS-located. A multivariate statistical analysis allowed an exploratory analysis to eliminate non useful and redundant variables and then to determine what variables appear to be important predictors of deforestation behavior among rural families. A resulting logistic regression model showed that household with lower annual income heads and with less use of conservation practices were more statistically prone to clear the forest (α = 0.001). The study uncovered the complexity of this problem and confirmed the need of using GIS–remote sensing techniques to combine socioeconomic and environmental data in several time–space dimensions to find the causes and trends of tropical deforestation.     

论村民小组的毁林犯罪主体

毁林犯罪的主体既可以是自然人也可以是单位,不同的定性结果当事人的刑事责任不同。村民小组长为了本组集体利益而实施的毁林犯罪,林业执法实践中有的按小组长个人犯罪处罚,有的则以单位犯罪论处。为了执法的准确与公正,本文从村民小组的法律地位和相关法律适用等方面,分析了村民小组在毁林犯罪中的单位犯罪主体资格。     

Upland agriculture,the land frontier and forest decline in the Philippines

Population pressure, expansion of small-scale agriculture and shifting cultivation are commonly cited as the causes of tropical deforestation. A close examination of deforestation and agriculture in the Philippine uplands reveals, however, that the vast majority of agriculturists must be sedentary farmers. In addition, the importance of population pressure as a cause of deforestation in the Philippines cannot be supported by the available evidence. Lastly, the concept of arable land is shown to be of limited value in discussing upland agriculture in the Philippines.     

National REDD + reference levels deduced from the global deforestation curve

This article proposes an approach to one of the most prominent problems for the establishment of a REDD + regime — namely reference level determination. We have developed a standardised approach for the consideration of national circumstances in REDD + reference levels, which applies the global curve of forest cover development as the benchmark for accounting of avoided deforestation. The approach draws on the identification and empirical quantification of a global deforestation curve which was created by applying the forest transition concept (Köthke et al., 2013). By the underlying regression model the most relevant national circumstances were identified as the average of 140 countries. These national circumstances represent the development stages of the individual countries, from which their future forest cover development in the global average can be determined.By applying national data for estimating the corresponding average development the article identifies national reference levels for 86 REDD + target countries which are still in their deforestation phase. It is estimated by how much actual deforestation in each country deviates from the mean deforestation curve; the period considered is 2005–2010. This is the first time a uniform global deforestation pattern was used to determine the consideration of national circumstances in REDD + reference levels. The quantitative results provided here may be an important basis for further policy discussions about reference level determination.     

Modeling susceptibility to deforestation of remaining ecosystems in North Central Mexico with logistic regression

Determining underlying factors that foster deforestation and delineating forest areas by levels of susceptibility are of the main challenges when defining policies for forest management and planning at regional scale. The susceptibility to deforestation of remaining forest ecosystems (shrubland, temperate forest and rainforest) was conducted in the state of San Luis Potosi, located in north central Mexico. Spatial analysis techniques were used to detect the deforested areas in the study area during 1993-2007. Logistic regression was used to relate explanatory variables (such as social, investment, forest production, biophysical and proximity factors) with susceptibility to deforestation to construct predictive models with two focuses: general and by biogeographical zone.In all models, deforestation has positive correlation with distance to rainfed agriculture, and negative correlation with slope, distance to roads and distance to towns. Other variables were significant in some cases, but in others they had dual relationships, which varied in each biogeographical zone. The results show that the remaining rainforest of Huastecaregion is highly susceptible to deforestation. Both approaches show that more than 70% of the current rainforest area has high and very high levels of susceptibility to deforestation. The values represent a serious concern with global warming whether tree carbon is released to atmosphere. However, after some considerations, encouraging forest environmental services appears to be the best alternative to achieve sustainable forest management.     

基于环境库兹涅茨曲线的森林资源变化问题研究评述

自上世纪90年代初环境库兹涅茨曲线提出以来, 涌现出大量关于环境质量同经济发展水平之间关系的研究。文中基于环境库茨涅兹曲线的视角, 总结了国内外近年来有关森林资源变化问题的研究进展, 认为森林资源环境库兹涅茨曲线研究仍未形成统-的定论, 在变量的选取、数据及模型的运用方面还存在进-步改进的空间。     

Factors influencing the loss of forest cover in bangladesh: An analysis from socioeconomic and demographic perspectives

Some studies have attributed forest shrinkage to population growth, economic development, conversion of forest land to agricultural use and harvesting of trees for timber and fuelwood. But the statistical support for these hypotheses is not strong. This paper attempts to test the above hypotheses statistically in the case of Bangladesh. Factor analysis extracted 4 important factors—(a) exploitation of forests for timber, fuelwood, tea, and shrimp production, (b) demographic pressure in agriculture, (c) economic development, and (d) expansion of crop lands—as causes of deforestation. The statistical test supports the hypotheses that the exploitation of forests for timber, fuelwood, tea and shrimp production, and conversion of forests to crop lands have a negative influence on forest cover. Economic development and demographic pressure in agriculture are also negatively correlated with forest cover. Results of regression analysis show the conversion of forests to agricultural land is the most important cause of deforestation. Other important causes, in order of their relative importance, are the relative price of forest products, population growth, economic development, demographic pressure in agriculture, increasing production of shrimps, export of tea and shrimps, increasing production of timber and fuelwood, and expansion of tea lands. The statistical tests support the above relationships.     

Carbon emissions due to land-use change and logging in Cambodia: a modeling approach

Land-use change and forestry in the tropics have caused huge carbon emissions to the atmosphere. The magnitude of these emissions, however, remains debatable. Therefore, there is a need to further develop appropriate methods that would reduce the estimation uncertainties. From a modeling perspective, this report is aimed at estimating carbon emissions from deforestation and logging activities in Cambodia just after it opened its door to the world. Recently available land-use and forest inventory data were used to develop simple models capable of estimating the change of carbon stocks in, and carbon emissions from, dryland and edaphic forests. This study estimated the annual deforestation rate to be 0.1 million ha between 1973 and 2003, or about 0.7%. Between 1993 and 2003, annual carbon emissions amounted to about 13.7 TgC, owing to deforestation and logging. The emissions calculated here are higher than those reported by the Cambodian government, which claimed that Cambodia was once a net sink of carbon. The models developed in this study will be a useful tool for further study of carbon emissions in tropical countries where selective logging is practiced. Part of this article was presented at the International Symposium on the Role of Forests for Coming Generations: Philosophy and Technology for Forest Resource Management, October 2004, Utsunomiya, Japan     

The impact of road geometry,surface roughness and truck weight on operating speed of logging trucks

Improved transport planning and pricing is dependent on correct cycle times. The objective of this study was to quantify the effect of road curvature, surface roughness, gradient and truck weight on the operating speed of a conventional 60-tonne gross vehicle weight logging truck. The study used a 320-km test track consisting of both public and forest roads. The track was driven with various gross vehicle weights. Speed data was retrieved from the truck’s CAN-bus system and road data was measured with a profilograph. The key factors for operating speed were curvature and surface roughness, both of which were correlated to each other as well as partially captured by functional road class. Regression analysis quantified the individual effects of these factors as well as gradient, undulation and interactions with truck weight. A regression model is presented which explained 80% of the variation in operating speed. The results were consistent with previous studies, and the proposed models can be used to improve transport planning, cost estimation, operative route path selection and road investments.     

基于PSR模型的中国生态文明建设国际比较

引入“压力—状态—响应(PSR) ”模型,从生态系统视角构建包括生态系统压力、生态系统健康和生态环境管理3个子系统共21个指标的生态文明评价指标体系; 采用全球60个主要国家(地区)的数据,从国际比较的视角考察中国生态文明建设水平和生态文明协调度。结果显示:中国生态文明综合指数排名第50位,与发达经济体的差距较大,在发展中经济体中位居中游,与我国当前的经济发展水平总体相适应; 中国生态环境管理表现相对优异,但生态系统压力和生态系统健康水平滞后,导致我国生态文明协调程度偏低。实证分析表明,一国生态文明建设水平与生态文明协调度存在显著的正相关性。我国在加强生态文明建设的过程中,应着力提升各子系统间的协调互动水平,特别是生态环境管理的实施效果。     

世界热带林现状及发展战略(上)

森林资源的消长与社会经济发展密切相关,而林业的兴衰又直接关系到国民经济和社会的发展。当前,世界林业面临的"四大危机"大部分又是与热带林的破坏密切相关的。因此,研究热带林发展战略是研究当前世界林业的核心问题。本文根据国际组织和各国的大量文献,着重就世界热带林的现状、毁林速度、毁林模式、原因和后果等问题进行了论述。     

Property rights,land conflicts and deforestation in the Eastern Amazon

In the Brazilian Amazon, insecure property rights are among the main causes of land conflicts and deforestation. Through an in-depth empirical case study in Maranhao in the Eastern Amazon, this research analyzes how distorted agrarian, forest and environmental policies, laws and regulations originated insecure property rights not only over land, but also over timber, which allied to social and political factors, such as uneven distribution of land and strong organization of landless peasants, led to land conflicts and deforestation. This paper also shows that the causes of and the several actors involved in the deforestation of the Amazon were not independent, rather they were related and interact to each other. Compatibility between environmental goals and agrarian policies, regulations and laws are necessary to provide secure and clear property rights to allow a better enforcement of environmental regulations and to give actors incentives to avoid deforestation.     

住宅建设项目交通影响评价与仿真研究

以项目周边的交叉口为主要评价对象,路段评价为辅的研究思路,提出交通影响度的模型与相应的评价方法。结合哈尔滨市某住宅建设项目为研究实例,对其周边路网的交通现状进行分析,评价进行提出改善路网交通状况的措施,并使用VISSIM交通仿真软件对改善效果进行评价。     

Analyzing the perception of deforestation drivers by African policy makers in light of possible REDD+ policy responses

As REDD+ countries are moving towards the implementation phase of their national REDD+ programs, it becomes crucial to better understand what drives deforestation in order to identify policy responses. This however, remains challenging because, while the number of scientific assessments of deforestation drivers is increasing, they often reach diverging conclusions. Deforestation drivers can have long underlying causal chains and take different shapes depending on the perspective that is chosen. As states are the official owners of forests in most African countries, analyzing the perspective of policy makers on deforestation in this context, helps revealing deforestation drivers that are harder to quantify, define and measure with usual proxies. It also potentially allows identifying politically and institutionally feasible deforestation reduction measures.In this paper content analysis is used to assess how African policy makers perceive deforestation drivers. We find that they strongly emphasize the role of institutional and policy drivers. Furthermore, we find that some of the complex issues related to forest governance in general, can be narrowed down to very specific problems. In light of these findings, we will argue that mechanisms and standards have to be found to allow institutional and policy drivers of deforestation to be addressed in the result-based payments phase of REDD+.     

An empirical comparison of two subject-specific approaches to dominant heights modeling: The dummy variable method and the mixed model method

The varying (local) parameter(s) in site index models can be treated as fixed or random. Two primary subject-specific approaches to height modeling, the dummy variable method (fixed individual effects) and the mixed model method (random individual effects), were compared using Chapman–Richards type models fitted to second-rotation loblolly pine (Pinus taeda L.) data from a designed experiment. For height prediction of new growth series, tested on our validation subset data, the mixed model provides a new (local) parameter prediction method (termed as mixed predictor), which generally performed better than the traditional method of recovering local parameters (the least squares (LS) predictor we used). However, using the LS predictor, both the dummy variable estimation method and mixed model estimation showed almost identical prediction results. With multiple pairs of height–age measurements, no big difference was found in empirical site index prediction between the LS and mixed predictor. Theoretically, one main advantage of the mixed model approach is the ability of its mixed predictor to predict several local parameters using a single height–age pair. However, our empirical results failed to support this point.     

凤县林麝栖息地干扰状况分析

陕西凤县的林麝资源曾经十分丰富。然而自20世纪50～60年代以来,随着森林采伐、农田开垦、道路铺设、矿藏开采等人类生产活动的开展,林麝的栖息生境出现破碎化趋势、面积不断缩减。目前凤县林麝分布区主要位于相对偏远、人为干扰较少的、植被相对保存完好的乡与乡的交界和县的边缘地区。本文总结并分析了各种人类活动对凤县林麝及其栖息地的影响,最后针对存在问题提出了相应的保护和管理建议。     

Climate Aid Will Neither Support Forests nor the Poor: No Hope for Saving the World's Forests

Political themes undergo specific political careers. They enter and leave political agendas. Themes in development policy are, for example, biodiversity, climate change, or deforestation. While political themes change, underlying principles of aid disbursement do not. Currently the discussion on Climate Aid, in particular the reduction of emissions from deforestation and forest degradation, puts again the emphasis to deforestation. Deforestation is a prominent theme, often defined as a “forest problem,” by foreign aid policies on forestry. Foresters are once again dubbed as being able to “save the World” all on their own. In fact, it is not them who on decide the priorities of foreign (aid) policy. The decisions made about cooperating countries and thematic areas do not stem from problem pressure. Political factors dominate the program formulation and financing. Analyses of European donors' forest aid reveal that, contrary to what is defined in policies, disbursements to countries, relevant to deforestation, are not prioritized. Also the goal of poverty alleviation is not served. Most of the funds are spent in countries of already relatively high human development. Countries with “rampant” corruption are given handouts as well as small island developing countries. On the basis of these results we can draw conclusions on the ability and efficiency of (future) Climate Aid that is hoped to serve forests and the poor.     

梁格法分析变宽斜预应力混凝土箱梁桥

变宽斜箱梁桥在公路、城市互通立交中应用广泛,其构造和力学特点与直线桥梁有很大区别,在运用程序建模分析中选择合适的方法对分析结果的精确度有着较大的影响。本文通过对某斜桥进行梁格法建模分析,介绍了梁格模型在变宽斜箱梁桥中的应用。