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1.
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.  相似文献   

2.
The dynamics of the Atlantic Rainforest loss and recovery are still not fully understood despite its long history of human occupation. In this study, we investigated changes in an Atlantic Rainforest region due to major biophysical and human proximate causes. First, we modeled land-cover and land-use changes from 1962 to 2000, including deforestation and forest regrowth, and thereby simulated future landscape trajectories to assess their possible effects on the conservation of forest species of the Ibiúna Plateau, a region located in Southeastern Brazil within the Atlantic Rainforest biome. We modeled four scenarios (status quo, random, lawenforcement, and land-use intensification) and simulated their resulting landscape trajectories for the year 2019 using DINAMICA. The landscape dynamics in the study region were particularly intense. During the first period of 1962–1981, the rate of forest regrowth (3% year−1) was greater than the rate of deforestation (2% year−1), whereas in the latter period of 1981–2000, increasing urbanization and the spreading of rural establishments resulted in more deforestation (2.9% year−1) than regrowth (1% year−1). These dynamics imprinted a heterogeneous landscape, leading to the predominance of progressively younger secondary forests with increasingly less capacity of hosting sensitive forest species. The influence of proximate causes on the dynamics of deforestation and forest regrowth showed consistent patterns, such as higher forest regrowth rates near rivers, on steep slopes and far from dirt roads, whereas losses in young secondary vegetation and forest were far from rivers, on gentle slopes and near urban areas. Of the modeled scenarios, only the law enforcement scenario may lead to the recovery of a network of interconnected forest patches, suggesting that simply the enforcement of current forest laws, which prohibit deforestation on unsuitable agricultural areas and along river margins and establish a minimum of 20% of forest remnant per rural property, may effectively favor forest species conservation in the short term (two decades) without the need of any forest restoration effort.  相似文献   

3.
Much of the dry tropical forest biome has been converted to agricultural land uses over the past several centuries. However, in conservation areas such as those in the Guanacaste and Tempisque regions of Costa Rica, tropical dry forests are regenerating due to management practices including fire suppression. To better understand the patterns of secondary succession occurring in Costa Rican tropical dry forest, we established 60 20 × 50 m plots in mature and regenerating forests in the Sector Santa Rosa (formerly known as Parque Nacional Santa Rosa) and Palo Verde National Park. Plots were stratified into three plant communities: tropical dry oak forest (Quercus oleoides) (SROAK), Santa Rosa tropical dry forest (SRTDF), and Palo Verde tropical dry forest (PVTDF). In these plots we measured and identified and all individuals >10 cm DBH, measured but did not identify stems <10 cm but taller than 1.3 m, counted woody seedlings (<1.3 m height) and analyzed soil chemical and physical properties.  相似文献   

4.
China has been implementing the world's most ambitious afforestation and forest conservation programs and undergoing rapid forest expansion since 1990s, thus, understanding the forest dynamics in China has global implications for sustainable forest management. Through analyzing forest area, biomass dynamics, and factors influencing deforestation and forest restoration, we found that the natural disasters and economic development drove forest dynamics and transition in China. The growth of the economy and population drove up demand for forest products, facilitating deforestation. The booming economy also boosted government's investment in forest restoration and conservation programs. Natural disasters damaged and frequently destroyed forests, but they also served as stimuli for the authorities to adopt remedy forestry policies and programs that ultimately led to forest increase. Nationwide, increasing peaks of annual afforestation were observed in the late 1950s, early 1980s, and early 2000s, and the newly increased area closed for forest restoration reached the peak in 1998. All these peaks were closely associated with peaks of natural disasters (i.e., floods, drought, and dust storm events). Based on the dynamics of forest area, biomass and forest consumption over the past 40 years, forest transition occurred during the late 1980s to the early 1990s, and it also strengthened the carbon (C) sink function of forests in China (with an increasing rate of 0.137 Pg C yr.1 during 1994–2008). Overall, our study highlighted the influences of natural disasters and economic development on the forestry policies and forest C dynamics in the newly industrialized country.  相似文献   

5.
In this article the authors contend that the constraints to including reduced emissions from avoided tropical forest deforestation and degradation in international carbon markets stem from problems associated with: (1) correctly measuring emissions savings from avoided tropical forest deforestation and degradation; (2) the permanence and ‘leakage’ of tropical forest conservation regimes; (3) ensuring economic incentives for the avoidance of tropical forest deforestation and degradation are sufficiently effective; (4) the exclusion of reduced emissions from avoided tropical forest deforestation and degradation from critical international climate change policy agreements; and (5) the behaviour of investors in carbon markets. Case analysis of the ‘Emissions Biodiversity Exchange Project for the 21st Century’ (EBEX21) program of Landcare Research New Zealand is used to examine how a government-supported market-based forest conservation initiative can be used to address these constraints, particularly in the context of small-scale forestry conservation.  相似文献   

6.
The highest deforestation and forest degradation rates in Africa occur in the dry forests and woodlands where pressure for land is increasing, poverty is rampant, livelihood options are few and climate change effects are severe. This paper examines factors that cause land and forest degradation in the Sahel and dry forests and woodlands of eastern and southern Africa and highlights some successful restoration practices, technologies and approaches. In the Sahel, enclosures are used to protect young growing trees while in East Africa enclosures are implemented on degraded land as a mechanism for environmental rehabilitation with a clear biophysical impact. The choice of techniques for rehabilitating specific degraded areas depends first on the priorities and management objectives of stakeholders followed by the costs and benefits associated with available rehabilitation techniques and the economic, social, and environmental values of the land resources in their current and desired future states. In the Sahel, sustainable land management is considered to be an imperative for their sustainable development and the practices include soil and water conservation activities and structures. In all regions, natural forest rehabilitation has used both natural and assisted regeneration to promote the growth of especially indigenous species through coppice regrowth and root suckers rather than seeds. Assisted regeneration was especially prevalent in the Sahel where indigenous tree species have been identified to dominate the degraded sites during early stages of secondary forest succession. The success of any rehabilitation activities depends on community-based natural resources management. In addition, the forest policies and their related policies need to be enabling in order to address issues of concern, including (1) the full participation of communities, (2) clear land and tree tenure and (3) equitable benefit sharing.  相似文献   

7.
Understanding tropical forest succession is critical for the development of tropical forest conservation strategies worldwide, given that tropical secondary forests can be considered the forests of the future. Tropical dry forests (TDF) are among the most threatened tropical ecosystems, there are more secondary forests and forest restoration efforts that require a better understanding of successional processes. The main goal of this synthesis for this special issue on the ecology and management of tropical dry forests in the Americas is to present a summarized review of the current knowledge of the ecology and management implications associated to TDF succession. We explore specific issues associated to tropical dry forest succession with emphasis on the use of chronosequences, plant diversity and composition, plant phenology and remote sensing, pollination, and animal–plant interactions; all under the integrating umbrella of ecosystem succession. We also emphasize the need to conduct socio-ecological research to understand changes in land-use history and its effects on succession and forest regeneration of TDF. We close this paper with some thoughts and ideas associated with the strong need for an integrating dimension not considered until today: the role of cyberinfrastructure and eco-informatics as a tool to support sound conservation, management and understanding of TDF in the Americas.  相似文献   

8.
The tensions between development and preservation of tropical forests heighten the need for integrated assessments of deforestation processes and for models that address the fine-tuned location of change. As Mexico’s last tropical forest frontier, the southern Yucatán peninsular region witnesses these tensions, giving rise to a “hot spot” of tropical deforestation. These forests register the imprint of ancient Maya uses and selective logging in the recent past, but significant modern conversion of them for agriculture began in the 1960s. Subsequently, as much as 10% of the region’s forests have been disturbed anthropogenically. The precise rates of conversion and length of successional growth in both upland and wetland forests are tied to policy and political economic conditions. Pressures on upland forests are exacerbated by the development of infrastructure for El Mundo Maya, an archaeological and ecological activity predicated on forest maintenance, and by increased subsistence and market cultivation, including lands on the edge of Mexico’s largest tropical forest biosphere reserve. In this complex setting, the southern Yucatán peninsular region project seeks to unite research in the ecological, social, and remote sensing sciences to provide a firm understanding of the dynamics of deforestation and to work towards spatially explicit assessments and models that can be used to monitor and project forest change under different assumptions.  相似文献   

9.
International policy incentives to promote tropical forest restoration, community forestry, and payments for environmental services have not been widely adopted at scale. It is possible that reducing emissions from deforestation and forest degradation and related activities (REDD+) could be a policy tool for encouraging larger scale restoration efforts in the tropics. Although there are political challenges to ensuring the inclusion of restoration activities in REDD+, its use might facilitate the forest transition in tropical countries, reduce carbon dioxide concentrations in the atmosphere, and garner political support for these policies and approaches.  相似文献   

10.
For the countries struggling with climate change, sustainable forestry is one of the greatest challenges and is difficult to define, implement, and to measure. According to the scientific community’s consensus on climate change, forests are one of the major sinks and sustainable forest management (SFM) is needed to prevent deforestation and its negative effects on natural ecosystems. Despite being a party to many international treaties/agreements related to land use policies (LUP) that are promoting SFM to protect and develop forest resources, the 2/B application in Turkish forest legislation has been causing deforestation in Turkey since the 1970s.

In this study, 2/B applications–political and legal process–causing deforestation by land use change (LUC) are investigated by carrying out a legal analysis. About 500.000 ha of forests have been lost due to the 2/B application and as a LUP directly affects SFM, carbon sequestration capacities (CSC), and therefore, climate change. To exemplify this pre and post-LUC change and effect, the amount of carbon that was prevented from being absorbed as 176,7 tonnes/ha on average in a given forest area for the year 2016. There is a vital need to address the negative effects of ill-defined forest legislation to achieve SFM.  相似文献   


11.
In Rondônia State, Brazil, settlement processes have cleared 68,000 km2 of tropical forests since the 1970s. The intensity of deforestation has differed by region depending on driving factors like roads and economic activities. Different histories of land-use activities and rates of change have resulted in mosaics of forest patches embedded in an agricultural matrix. Yet, most assessments of deforestation and its effects on vegetation, soil and water typically focus on landscape patterns of current conditions, yet historical deforestation dynamics can influence current conditions strongly. Here, we develop and describe the use of four land-use dynamic indicators to capture historical land-use changes of catchments and to measure the rate of deforestation (annual deforestation rate), forest regeneration level (secondary forest mean proportion), time since disturbance (mean time since deforestation) and deforestation profile (deforestation profile curvature). We used the proposed indices to analyze a watershed located in central Rondônia. Landsat TM and ETM+ images were used to produce historical land-use maps of the last 18 years, each even year from 1984 to 2002 for 20 catchments. We found that the land-use dynamics indicators are able to distinguish catchments with different land-use change profiles. Four categories of historical land-use were identified: old and dominant pasture cover on small properties, recent deforestation and dominance of secondary growth, old extensive pastures and large forest remnants and, recent deforestation, pasture and large forest remnants. Knowing historical deforestation processes is important to develop appropriate conservation strategies and define priorities and actions for conserving forests currently under deforestation.  相似文献   

12.
The mountainous mainland Southeast Asia region, that covers adjoining parts of Cambodia, Lao PDR, Myanmar, Thailand, Vietnam and China, contains the region's largest remaining tropical forest. The people living in the forested mountains, who belong to a diversity of ethnic minority groups, possess a wealth of local knowledge and skills in forest management. With rapid decrease in forest area, implementation of forest conservation policies, improved access to market and replacement of shifting cultivation with permanent cropping, land use and management in the region has been rapidly changing. Some indigenous knowledge and technology in forest management will inevitably continue to be lost in the process, but not all. This paper shows how local forest management systems have been adapted to deal with the change, with specific focus on deployment and adaptation of indigenous knowledge and skills. First background on the region and its traditional land use systems will be provided. A review will then be made of the cropping system changes that have been taking place and their driving forces and how local farmers have adapted indigenous knowledge and skill in forest management to meet current needs and conditions. Cases drawn from studies in the region will illustrate how deployment of indigenous technology not only helps the farmers to improve their productivity but can also provide services in forest regeneration and biodiversity conservation. To do this farmers, including those who were former migratory opium growers, make use of the knowledge of their own environment and locally available genetic resources and the community's organizational and management skills. It will also be shown that farmers’ knowledge and skills are not static, but continually revised and integrating modern inputs as well as transfer of new ideas and innovations.  相似文献   

13.
Considering the pressures on tropical forests from deforestation and the recent expansion of harvesting through forest concessions in the Brazilian Amazon, it is imperative that forest management systems are scrutinized to ensure sustainability. One of the basic problems in forest management is the correct identification of species within the forest stand. While this is a well known issue, little consideration is given to how to mitigate this problem or its affects on management practices and conservation. This paper examines the current practice of forest inventories in the Brazilian Amazon, as part of the mandatory system of reduced impact logging (RIL), using extensive forest inventory verification. The results show that the RIL management plan implemented in the project area was based on a highly inaccurate forest inventory. At least 132 species or 43.5% of all species identified after botanical checking did not appear in the forest inventory and the common practice of matching vernacular names to scientific ones proved to be severely deficient. In contrast, a high percentage of field identifications based on local people's expertise were correct. We suggest changes to current practices, including the training and use of parataxonomists, the collection of samples for verification, and stricter government control over current practices, which will achieve greater accuracy in data collection and forest management planning. Ultimately, we argue that in the current climate of extensive deforestation and forest use, it is essential that all aspects of RIL systems are reevaluated in order to achieve economic and ecological sustainability.  相似文献   

14.
An overview of the forestry sector in Costa Rica was undertaken to determine whether the existing management practices of timber resources hold the potential to meet the country's demands for timber in the immediate decades to come, and to identify changes that might be needed in the management of forested lands. To meet these goals, we examined the present status and potential future contribution of the two newest forest sectors: the management of natural forest and plantation forestry. Rcsults indicate that the present management of Costa Rica's timber resources does not hold the potential to meet the country's demands for timber for more than the next ten years without severe loss of its forests. Substantial progress is occurring, but at an insufficient rate. Moreover, despite the considerable headway made in conservation in recent years, the rate of deforestation remains high. A number of factors limit advancement in natural forest management and plantation forestry, both of which have the potential to deaccelerate deforestation. In natural forest management, constraints are the rate at which forests are being brought under management, lack of budgetary provisions for fiscal incentives to private owners who alone cannot be expected to bear the cost of benefits of natural forest management that are national or even global in their distribution, and the weak infrastructure, extension services and research support to meet management goals. In the case of plantation forestry, the capability of this sector to produce commercial timber is not known. Moreover, inadequate management and extension services together with the misuse of the incentive system by private owners is likely to limit the potential of plantations. Institutional constraints include outdated legal and bureaucratic framework, market interventions, absence of clear policy toward natural forest management and plantation forestry, poor investment in infrastructure, extension and research support, and inadequate interaction among various agencies responsible for the development of the forestry sector. Such institutional constraints have allowed the proliferation of disincentives against the development of a sustainable timber sector. If the Costa Rican government's objective is to encourage sustainable forestry, it must first clearly articulate the policy and then create the appropriate legal, economic and institutional framework for implementation of the policy. Costa Rica, with its enlightened public administration system, vast technical and scientific knowledge about its forest ecosystem and extensive assistance from international organizations, must succeed, otherwise prospects for sustainable forestry in thc less fortunate tropical countries would be bleak.  相似文献   

15.
Blakesley  David  Hardwick  Kate  Elliott  Stephen 《New Forests》2002,24(3):165-174
Some governments in Southeast Asia, such as those of Thailand and Vietnam have clear policies to restore large areas of degraded land to native forest. However, knowledge needed for the success of these ambitious programmes is still inadequate, and considerable further research is required. Furthermore, very little literature is available to conservation practitioners about the restoration of tropical forests for biodiversity conservation. This paper introduces the framework species method of forest restoration, which is being developed to restore forests in Thailand. The paper examines the potential for adoption of this technique in different forest types across the Southeast Asia region, and identifies priorities for future research needed before the method can be widely implemented. These include the identification of forest types, the selection of candidate framework species, maintenance of genetic diversity, and development of methods of seed collection and germination.  相似文献   

16.
The implementation of carbon-storage efforts in countries experiencing armed conflicts or confronting illegal activities (such as illicit crop cultivation) will permit additional tropical forests to be protected for climate change mitigation. Yet, despite these potential gains, the appropriate design and application of forest conservation and climate change mitigation approaches such as the mechanism for Reducing Emissions from Deforestation and Forest Degradation (REDD +) in such contexts remain little studied. Unanswered questions relate to the propensity of farmers in conflict affected areas to conserve forests for climate change mitigation. Such questions include, for what reasons and under what circumstances would such farmer participate in climate change mitigation activities? In this paper we address these questions by developing an econometric Logit model to understand factors influencing the propensity to conserve forest of farmers from 14 villages in Colombia. These villages are located in a region recognized as a stronghold of guerrilla insurgencies and as the center for illegal crop cultivation. The region was selected as it is also the proposed target area for piloting Colombian government REDD + activities. A household survey (n = 90) showed that four explanatory variables are significantly related to the ‘propensity to conserve forest’. ‘Harvest of non-timber forest products’ (specifically bush meat) positively influences a farmer's propensity to conserve forest. In contrast, higher ‘percentage of forest area’, ‘deforestation for (the production of) subsistence crops’ and ‘harvest of wood product’, each have a negative influence. Overall, results show an already high propensity to conserve forest among farmers (70% of respondents) and indicate their growing propensity toward the conservation of primary forest and management of degraded lands and secondary forest. These results might be attributable to efforts undertaken to reduce the causes of armed-conflicts and ecosystem deterioration, such as enhancement of land tenure security and farmer associations' rules to reduce deforestation. They might also be linked to communities' positive attitudes toward water resources conservation. We conclude that most farmers will not oppose forest conservation as long as it is compatible with their respective livelihood priorities.  相似文献   

17.
Accurate information concerning regional to ecosystem-scale carbon dynamics within tropical rainforests is important because of the increasing certainty that the global climate will change significantly within the next century. Tropical forests of north Queensland, Australia, are highly sensitive to climate change and substantial shifts in the distribution of these forests are likely to occur with minor variations in climate. The focus of this research was the development of a model-based system for assessing forest growth and biomass accumulation dynamics within Australia's tropical rainforest bioregion and predicting the impacts of climate change on these dynamics. This paper presents the parameterisation and calibration of (a) the 3-PG (Physiological Principles Predicting Growth) model to a selection of restored rainforest and commercial timber plantations and (b) a modified version 3-PGS which uses satellite data, enabling the spatial assessment of mature tropical rainforest growth and production throughout the wet tropics bioregion. Statistically significant relationships were observed between 3-PG and 3-PGS modelled and field measured estimates of stand structural attributes including, basal area (BA), diameter at breast height (DBH) and above-ground biomass (AGB) throughout the bioregion. 3-PG and 3-PGS modelled leaf area index (LAI) and net primary production (NPP) related well to published estimates at other similar rainforest sites. These results indicate that the simple, process-based models are effective at capturing the growth dynamics of structurally complex old-growth, restoration and plantation rainforests.  相似文献   

18.
Despite the ecological and economical importance of tropical forests they are currently affected by human activities, mainly through deforestation and selective extraction. With the aim of making an opportune diagnosis of the condition of forests, we developed an ecological index based on qualitative and semi-quantitative data, allowing a quick diagnosis in order to manage and conserve tropical forests. We evaluated 44 plots of tree vegetation, measuring canopy height, number of strata, tree cover, dominant trees, number of tree species, as well as the management of and damage to the forest. The data of each parameter was classified in categories of 3, 4 or 5, which were normalized between 0 and 1 for the worst and best characteristics, respectively. For the purpose of analysis, the average, a set of IF–THEN rules, and fuzzy logic were applied and as a result we obtained a model that measures the ecological condition of the tropical forests. The model has the advantages of having an ecological basis, allows data to be gathered quickly and is clear and easy to manage and interpret. When running the model, the value of each intermediate variable is displayed, thus allowing the detection of where necessary action is required to improve the ecological condition of the forest. We expect this index to contribute in evaluating the effectiveness of forest management and possibly offer advice for the short-term management and conservation of the remnants of tropical forests.  相似文献   

19.
非法采伐及相关贸易被认为是导致毁林和全球气候变暖的主要原因之一,对全世界的经济、社会和环境带来了负面影响。中国是全球第1大林产品贸易国,进口木材已占我国木材来源的50%以上,而其中很多来自非伐采伐风险比较高的热带国家/地区,倍受国际舆论压力。在此背景下,中国政府正在不断完善相关法规政策以加强对进口木材合法性的管理。文中采用静态GTAP模型模拟了出台进口材合法性管理政策法规背景下企业选取不同合规机制对中国和全球林产品贸易的影响。结果表明,中国加强进口材合法性的管理将改变中国木材进口格局,其产生的主要福利损失由中国和被判定为非法采伐高风险的国家/地区承担,而低风险国家/地区则实现了福利增加。  相似文献   

20.
We focused on key aspects of forest governance for biodiver- sity conservation in implementing new climate change policies. The national forest institutions must be adaptive to identify the existing pitfalls of prior conservation policies to take advantage of new climate change policies. Strengthening roles and technical capacity of national institutions for systematic biodiversity monitoring and carbon stock assessment is required in developing and least developed countries. Community participation needs careful analysis to ensure equitable ac- cess of particular social groups to local decision-making processes and to sustain optional livelihoods. The livelihood options around forest reserves or protected areas must be taken into account to enhance forest-based adaptation.  相似文献   

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