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1.
This article examines two key aspects of land‐cover change in the south of the Chocó region. First, it assesses and compares the local impact on forest condition of labor‐intensive and capital‐intensive commercial logging. Second, it assesses the regional significance and permanency of these changes. Studies of land‐cover change associated with commercial logging have focused almost exclusively on capital‐intensive extraction and have assumed that after logging, degraded forests are transformed into agricultural cover. This study shows that both capital‐ and labor‐intensive logging result in similar land‐cover changes (i.e., forest degradation) if the timber sought is the same. However, labor‐intensive loggers also seek timber species not sought by capital‐intensive loggers, and this impact is statistically different from the impact of the extraction of the first group of species. Results also show that only a small fraction (20–30 percent) of the area logged is later converted to agricultural cover types. The persistence of logged forests means that up to 20 percent of the remaining forest cover could correspond to forests with significant and lasting levels of degradation. Furthermore, the different production requirements for each group of species also mean that there is a spatial differentiation in the impact of logging in the region. Logged forests are arranged into two consecutive corridors on each side of access routes (e.g., rivers). The first corridor corresponds to a narrow (approximately 1‐km) band of high‐intensity degradation. The second, broader (approximately 2‐km) forest band, with lower levels of degradation, extends inland along first‐tier corridors. A key factor determining the permanency of this land‐cover pattern is the strong control local communities have over the land in the region. This limits the spread of patterns observed in other frontier areas, especially the conversion of logged forests into agricultural cover. 相似文献
2.
As the major component of terrestrial ecosystems, forests play an irreplaceable role in providing ecosystem services and products (e.g. biodiversity, carbon sequestration, water yield and timber). Spatially quantifying ecosystem services and interactions will shed light on sustainable forest management. Main forest ecosystem services including carbon storage, water yield, soil retention and wood volume in the Ganjiang River Basin (GRB) were evaluated and mapped through the integrated use of InVEST3.1.0, CASA modeling and ArcGIS10.2, and relationships between forest ecosystem services and natural or social-economic factors were quantified and discussed based on ArcGIS10.2 and SPSS19.0. Results showed that the spatial pattern of the four ecosystem services is heterogeneous. Forests dominated by broad-leaved forest and bamboo forest in mountainous regions around the GRB provided the largest carbon storage and wood volume services, while forests dominated by Masson pine plantations or Chinese fir plantations in the northeast provided the largest water yield service. The spatial pattern of the soil retention service is more discrete than others, and forests in the southwestern regions showed larger soil erosion modulus than in the northeastern regions. Ecosystem services are closely related to the environmental process and human activities. With altitude or slope increases, the carbon storage and wood volume of forests increased and water yield depth and soil retention decreased. When the regional total population decreased or GDP per capita increased, carbon storage and wood volume increased. Further research into the interactions between environmental factors and ecosystem services is needed in order to understand environmental constraints when dealing with ecological problems. 相似文献
3.
Forest cover change in highland pine-oak forests of Michoacan, Mexico is due to a process of conversion of natural forests to avocado orchards. Privately-owned avocado orchards are found on land that was common forest before the 1992 Reform of the Mexican Constitution. We ask how forest cover change was facilitated by policy changes that affected land tenure rules and existing community forestry programs. We use a comparative case study of four communities, an analysis of forest cover change, and interviews and household surveys. Results show that 33.1% of forest cover was lost over a 16-year-period across the region. However, two forestry case study communities lost 7.2% and 15.1% of forest cover, while two adjacent non-forestry communities lost 86.5% and 92.4%, respectively. Interview data show that the Reform of Article 27 combined with the 1992 Forestry Law led to collapse of local governance, illegal division of common forests, and illegal logging in the two non-forestry communities. 相似文献
4.
《The Professional geographer》2013,65(4):477-490
Abstract This article examines two key aspects of land-cover change in the south of the Chocó region. First, it assesses and compares the local impact on forest condition of labor-intensive and capital-intensive commercial logging. Second, it assesses the regional significance and permanency of these changes. Studies of land-cover change associated with commercial logging have focused almost exclusively on capital-intensive extraction and have assumed that after logging, degraded forests are transformed into agricultural cover. This study shows that both capital- and labor-intensive logging result in similar land-cover changes (i.e., forest degradation) if the timber sought is the same. However, labor-intensive loggers also seek timber species not sought by capital-intensive loggers, and this impact is statistically different from the impact of the extraction of the first group of species. Results also show that only a small fraction (20–30 percent) of the area logged is later converted to agricultural cover types. The persistence of logged forests means that up to 20 percent of the remaining forest cover could correspond to forests with significant and lasting levels of degradation. Furthermore, the different production requirements for each group of species also mean that there is a spatial differentiation in the impact of logging in the region. Logged forests are arranged into two consecutive corridors on each side of access routes (e.g., rivers). The first corridor corresponds to a narrow (approximately 1-km) band of high-intensity degradation. The second, broader (approximately 2-km) forest band, with lower levels of degradation, extends inland along first-tier corridors. A key factor determining the permanency of this land-cover pattern is the strong control local communities have over the land in the region. This limits the spread of patterns observed in other frontier areas, especially the conversion of logged forests into agricultural cover. 相似文献
5.
JOBY BASS 《Geographical review》2005,95(4):556-577
ABSTRACT. As visible, material expression of human activities and goals, the landscape communicates as well as reflects. Specific landscapes communicate specific messages within the public sphere of which they are a part. In Honduras, many plaza landscapes have seen recent changes in form and in what they communicate. Once open, treeless spaces, many Honduran plazas are now filled with trees. These trees often support signs announcing the virtues of forests, linking the trees themselves to the official discourse on forest issues and illuminating the role of public‐space landscapes in influencing public perception. This article points out the links between such iconographic landscapes and the complex, multitiered environmental issues that are part of environmental conditions and their perception by local actors. 相似文献
6.
The transformation of tropical ecosystems by humans have resulted in forest loss, which, in turn, have caused negative impacts on biodiversity and the provisioning of ecosystem services. There is an urgent need to plan the restoration of these human-modified landscapes, using methodological approaches that consider key processes occurring at different spatial scales while engage local community participation, offering them the best possibilities of tangible benefits. In this study, was evaluated the landscape spatial pattern and local conservation status of existing forest remnants, showing an analysis of possible restoration scenarios for a human-modified landscape in La Montaña, an indigenous region in southwestern Mexico. Therefore, landscape and local scale approaches were linked to identify specific landscape elements where efforts to improve connectivity must be concentrated. Also, this approach allowed finding a set of species from reference sites that showed the best socioecological characteristics to be used in different restoration strategies. As expected, La Montaña region showed a spatial pattern typical of highly human-modified landscapes, i.e., several small (<21 ha) and irregular forest remnants with strong forest edge effects. Furthermore, these small and irregular forest fragments displayed forest structure, diversity and composition characteristics similar to those communities disturbed by selective harvesting or in an early successional phase. However, about 100 of woody species were found inside the fragments, some with important potential to provide ecosystem services. The landscape connectivity was very low, and an analysis of possible restoration scenarios showed that is equally important to restore the productive areas as well as open forest, to recover up to 47% of landscape connectivity. In this sense, it was proposed a productive restoration strategy to enrich open forests and create biodiversity-friendly habitat in agricultural areas, using species with high socioecological potential. We believe that the same approach could be applied to other highly human-modified tropical landscapes with similar socioecological problems. 相似文献
7.
Successful implementation of a forest based climate change mitigation mechanism such as REDD + depends on robust and available methods for measurement and estimation of forest degradation. Currently available methods are for application in single-hit degradation incidents in high density humid forests. However, it has been suggested that gradual degradation, especially in dry forests, is more widespread and that methods are needed for measuring and estimating associated emissions. We assess the applicability of an indirect remote sensing approach for monitoring forest degradation: infrastructure and other indicators of human activities are mapped and used for spatial prediction of degradation activities. For proxy variables we tested distance to forest edge, distance to roads, and population pressure calculated as the sum of inhabitants per pixel in the Landscan 2010 population raster dataset multiplied by an inverse power distance decay function. Wood extraction incidents were counted in 160 plots in two dry forests in Tanzania with infrastructural entry from one side only. We analyzed the spatial pattern of forest degradation as a function of the chosen proxy variables using zero inflated count models which allows for an excess of zero counts. A jack-knife bootstrap using 10,000 runs was applied to optimize the population distance decay function. We found that the impact of forest degradation is highest near high population concentration, above 1000 individuals. Furthermore, distance to nearest forest edge or road was a significant proxy for estimation of the number of wood extraction incidents (p < 0.001), where degradation incidents decreased with increasing distance to forest edge or road. At 3000 m from the forest edge towards the forest core the probability of wood extraction is 20% and dropping. The population distance decay function was found to have a steep decline indicating a relative small impact on forest degradation. Further, and perhaps larger, studies are needed to be able to recommend a distance decay function for general application in Tanzania. However, the results are useful for understanding spatial patterns of wood harvesting as a function of distance to nearest forest edge or road in dry Miombo woodland areas with average population pressure at 1685 ± 101 persons within a radius of 4000 m from the wood extraction sites. 相似文献
8.
Monitoring degradation in arid and semi-arid forests and woodlands: The case of the argan woodlands (Morocco) 总被引：1，自引：0，他引：1
Yann le Polain de Waroux 《Applied geography (Sevenoaks, England)》2012,32(2):777-786
Arid and semi-arid forests and woodlands (hereafter called «dryland forests»), in spite of their ecological and social importance, have received little attention in land change studies. Growing evidence shows that these forests have been receding at very high rates in many places, suggesting a need for a better understanding of the processes and causes of dryland forest degradation. Changes in the extent of dryland forests are debated in part because estimates of forest and woodland areas in drylands are uncertain. Causal explanations of the degradation tend to draw on the literature on desertification and tropical deforestation, and to emphasize either local or remote, and either social or biophysical drivers. This study contributes to a better understanding of dryland forest degradation as a basis for conservation policies. Firstly, we argue that monitoring arid and semi-arid forests and woodlands using area estimates may lead to an underestimation of the severity of change because tree density change often exceeds area change. Secondly, we argue that the analysis of degradation processes in these multifunctional landscapes should integrate both local and remote, and both social and biophysical factors. We use a case study of degradation in the argania woodlands in semi-arid to arid Southwest Morocco to test these two claims. We used gridded tree counts on aerial photographs and satellite images to estimate forest change between 1970 and 2007, and we tested several possible causes of change on the basis of original socio-economic field surveys and climatic and topographic data. We found that forest density declined by 44.5% during this period, a figure that is significantly underestimated if forest area change is used as a measure of degradation. Increasing aridity and, to a lesser extent, fuelwood extraction were related to forest decline. No effect of grazing by local livestock was found. 相似文献
9.
Emily Benton Hite David Barton Bray Elvira Duran Armando Rincón-Gutiérrez 《社会与自然资源》2017,30(5):613-626
Studies of coffee agroecosystems have focused on their role in providing habitat for biodiversity across a range of management intensities. These studies have not taken into account the temporal and spatial transformations in coffee landscapes and their impacts on structural heterogeneity and biodiversity, nor systematically linked these transformations to farmer management responses to price and policy shocks. We utilize a coupled natural–human system framework to examine the historical transformations of the coffee landscape in a matrix of community-protected forests in a coffee-growing community in Oaxaca, Mexico, and study how those transformations impact tree biodiversity across a range of management options, including formerly certified organic and conventional coffee, abandonment, and conversion. The coffee landscape has historically transitioned from forests and fields (1950s–1960s) to one dominated by coffee (1970s–1980s) to a richly mosaic and biodiverse landscape (1990–2010) resulting from 43% recent abandonment and conversion of coffee back to forest and fields. 相似文献
10.
An abrupt ice and snow storm disaster which occurred in the spring of 2008 se-verely destroyed forests over a surprisingly large portion of southern China.A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mountain-Wuyi Mountain was selected as the study area.The authors integrated field data collected in two field surveys to analyze the impacts of the disturbance on forests.The following results were obtained.(1) The extent of damage to plantations along the transect decreased in the order of slash pine > masson pine > mixed plantation > Chinese fir.Slash pine is an introduced species from southern America which is characterized by fast growth,low wood quality and rich oleoresin,and showed a damage rate of 61.3% of samples,of which 70.4% cannot recover naturally.Masson pine is the native pioneer species of forests with harder wood,and 52.5% were damaged due to turpentine,of which 60.9% cannot recovery naturally.Chinese fir is a local tree species and samples showed a rate of 46% and a relative rate of 32.5%,lower than the mixed plantation.(2) From west to east along the transect,we can see that evergreen broad-leaved forest of the western transect on Jinggang Mountain showed the lightest damage extent,and a Cryp-tomeria plantation at an altitude of 700 m was severely destroyed while Chinese fir showed light damage below 700 m and relatively severe damage above 900 m.Masson pine and slash pine in the central transect in Jitai Basin were damaged severely due to turpentine ac-tivities,and closed natural secondary deciduous broad-leaved forest was damaged severely due to high ice and snow accumulation on intertwined shrubs.Masson pine aerial-seeding plantations below 400 m along the eastern transect in Xingguo and Ningdu counties were nearly undamaged for small tree sizes,and Chinese fir at 500-900 m altitude showed a lighter damage extent.However,masson pine which was distributed above 400 m and planted in the 1960s,was severely damaged due to turpentine. 相似文献
11.
Bharat Prashad BHATT Sagar GODAR CHHETRI Thakur SILWAL Megharaj POUDEL 《资源与生态学报(英文版)》2021,12(5):620-627
Forests are major sources of energy, timber and non-timber forest products, medicinal and aromatic plants, hydrological functions, biodiversity conservation, and also fundamental sources of revenue collection to the nation. Studies indicate that forests could significantly enhance economic growth and create employment opportunities for local communities under intensive management. This paper aims to predict the contribution of the forest sector to the national economy. The economic facets of forestry considered in this paper are revenue generated from timber, non-timber forest products (NTFPs) and medicinal and aromatic plants (MAPs), and protected areas. The ARIMA model was used to forecast the economic contribution of the forestry sector. The study found that the total revenue generated from the selling of timber and fuelwood (USD 50.19 million) was higher than the total revenue collected from protected areas (USD 37.58 million) and NTFPs/MAPs (USD 6.9 million) in the past 15 years. The model projected that the mean revenue for the timber and fuelwood sale will USD 3.5 million for the next ten years. Similarly, the mean revenue will be generated about USD 0.5 million and USD 6.2 million from NTFPs/MAPs and protected areas, respectively, for the next ten years. The study limits to take account the in-kind use of forest products such as timber, fodder, fuelwood, etc., as used by community people within a forest users’ groups. Thus, practicing sustainable forest management, enabling policy documents, establishing forest-based industries, establishing forestry nurseries, conducting agroforestry practices, and tenure security could enhance the forestry sector's economic aspects. 相似文献
12.
E. N. Tagieva 《Geography and Natural Resources》2012,33(1):100-103
Field observations were used in compiling the map for contemporary vegetation of the Acinour-Ceyrançöl foothill areas having regard to the altered floristic composition of steppe and semidesert plant communities. The study revealed a decrease in the area occupied by juniper sparse forests and riparian forests. It is found that a severe anthropogenic influence in this area leads to desertification and degradation of landscapes. 相似文献
13.
The detection of vegetation fires using remote sensing has proven useful for highlighting areas undergoing rapid conversion in humid forests, but not in tropical dry forest (TDF). To further understand this relationship, we explored the correlation between MODIS Active Fires and forest cover change at local scales using 3 × 3 km sampling grids in three TDF landscapes in Bolivia; Mexico, and Brazil. Our analysis showed no single overall correlation among sites between the frequency of fires reported by the MODIS Active Fire Mapping product and forest cover change. Also, aggregated patterns of fire occurrence in Brazil and Bolivia did not correspond to areas with high percentage of forest loss, which indicates that the fire/deforestation relationship in TDF is not apparent in a simple fire frequency map. However, statistically significant correlations were found in sampling boxes with 50–60%, 50–70%, 50–95% forest cover at “initial state” of the time series in the Mexican site, Bolivian site and Brazilian site, respectively. Our findings suggest that complex interactions between anthropogenic fire-use, satellite-detected fires, and deforestation in highly fragmented TDF landscapes are difficult to describe at regional scales and might only be possible to analyze using finer resolution sampling grids. 相似文献
14.
Deforestation and forest degradation are proceeding rapidly in the lowland forests of Indonesian Borneo. Time series analysis of satellite imagery provides an ideal means of quantifying landscape change and identifying the pathways which lead to the changes. This study investigates the forest and land cover changes by classifying Landsat MSS (Multispectral Scanner), TM (Thematic Mapper) and ETM+ (Enhanced Thematic Mapper Plus) images over three time periods (1983–90, 1990–98, and 1998–2000), creating land cover maps for each year and change trajectories for each year-pair. The study area chosen covers an area of 2160 km2 of undulating topography and alluvial plains in the East Kutai District of East Kalimantan Province, which in the 1980s was covered mostly with lowland dipterocarp forest; today the landscape is a patchwork dominated by oil palm and timber plantations and degraded forest. We relate land cover change data to land use allocation and to fire impacts based on fire hotspot distribution and fire damage information. The multidate land cover change trajectories provide an insight into the forest loss and degradation pathways over the 17-year period spanning the first entry of commercial logging concessionaires, followed by a government-sponsored transmigration scheme, government-licensed timber and oil palm plantations and, finally, the devastating fires of 1998. The results show a mean deforestation rate of 42 km2 or 6 per cent per year for 1983–2000, rising to 10 per cent per year for 1990–98; by 2000, 70 per cent of forest initially damaged by fire and drought during the 1982–83 El Niño event was classified as non-forest. Although our study area is perhaps a worst-case scenario in terms of land use planning outcomes, the lessons from this research are directly applicable to scenario prediction for informed forest and land use planning and monitoring. 相似文献
15.
An abrupt ice and snow storm disaster which occurred in the spring of 2008 severely destroyed forests over a surprisingly large portion of southern China. A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mountain-Wuyi Mountain was selected as the study area. The authors integrated field data collected in two field surveys to analyze the impacts of the disturbance on forests. The following results were obtained. (1) The extent of damage to plantations along the transect decreased in the order of slash pine > masson pine > mixed plantation > Chinese fir. Slash pine is an introduced species from southern America which is characterized by fast growth, low wood quality and rich oleoresin, and showed a damage rate of 61.3% of samples, of which 70.4% cannot recover naturally. Masson pine is the native pioneer species of forests with harder wood, and 52.5% were damaged due to turpentine, of which 60.9% cannot recovery naturally. Chinese fir is a local tree species and samples showed a rate of 46% and a relative rate of 32.5%, lower than the mixed plantation. (2) From west to east along the transect, we can see that evergreen broad-leaved forest of the western transect on Jinggang Mountain showed the lightest damage extent, and a Cryptomeria plantation at an altitude of 700 m was severely destroyed while Chinese fir showed light damage below 700 m and relatively severe damage above 900 m. Masson pine and slash pine in the central transect in Jitai Basin were damaged severely due to turpentine activities, and closed natural secondary deciduous broad-leaved forest was damaged severely due to high ice and snow accumulation on intertwined shrubs. Masson pine aerial-seeding plantations below 400 m along the eastern transect in Xingguo and Ningdu counties were nearly undamaged for small tree sizes, and Chinese fir at 500-900 m altitude showed a lighter damage extent. However, masson pine which was distributed above 400 m and planted in the 1960s, was severely damaged due to turpentine. 相似文献
16.
研究了在不同形式人类经济活动下的森林景观变化与西双版纳地区鸟类多样性的关系．同时对发展生产时的用地布局和维护森林景观的动态发展与提高人们生活质量和持续发展的关系进行了讨论． 相似文献
17.
贵州省森林资源动态变化 总被引：7，自引：1，他引：7
依据贵州省林业调查规划院1979、1984、1990、1995、2000年5次森林资源连续清查资料,从森林资源面积、蓄积量、组成结构等方面总结了该省近20年间森林资源动态变化的详细资料,并对变化的原因进行了分析。结果表明,20世纪70年代末至80年代末,林业用地面积、天然林面积与蓄积量均呈下降趋势;其后,由于贵州省政府及林业部门的高度重视,实施一系列林业生态保护与可持续发展工程,如国家“长江防护林工程”、“珠江防护林工程”等,贵州森林资源自1990年以来持续稳定增长,促进了生态环境改善 相似文献
18.
Finn Danielsen Christopher E. Filardi Knud A. Jønsson Victor Kohaia Niels Krabbe Jan B. Kristensen Robert G. Moyle Patrick Pikacha Michael K. Poulsen Mikael K. Sørensen Charles Tatahu Joseph Waihuru Jon Fjeldså 《Singapore journal of tropical geography》2010,31(1):100-114
Anthropogenic habitat changes and the introduction of pigs, dogs, cats and rats have caused a catastrophic decline in the terrestrial biodiversity of Pacific archipelagos. At present, economic globalization and an increased demand for timber are promoting industrial logging and plantation expansion. Commercial logging can be sustainable but in practice it more often leads to land degradation, especially on small flat islands. On large and mountainous islands, however, more modest impacts can be expected as the narrowly endemic species tend to inhabit montane forests where logging is difficult. In this study we use ornithological data collected at different elevations to assess the extent to which the avifauna of Makira, a large mountainous island in Melanesia, will be affected by deforestation of the lowlands, most of which are under timber concessions. Our data suggest that a majority of the endemic bird species use lowland forest to some extent and that this may even apply to species hitherto associated with montane forest. If current commercial forestry programmes are continued, the forest habitat may be disturbed or lost over large parts of Makira, potentially undermining the natural resource base for the local subsistence economy, exacerbating climate change and threatening the integrity of one of the most important areas for biodiversity conservation on earth. Our study highlights the importance of understanding the habitat requirements of endemic species and the urgency of establishing and effectively managing community-based protected areas in suitable lowland forests of the Pacific. 相似文献
19.
There has been a huge surge in interest in the preservation of Madagascar's forests in the past two decades, but despite the investment of hundreds of millions of dollars, the goal remains elusive. Recent legislation has given the government the authority to enter into contractual arrangements with communities for the management of the country's public forests, so it has become crucial to grapple with the significant challenges involved. This paper explores the enormity of the challenge of forest governance in Madagascar in an era of decentralization. By examining several forests in one part of the country, it reveals a dizzying range of forest types and forms of use and governance within a fairly small portion of the country. These examples make it apparent that the history of forest management in Madagascar constitutes a broad-ranging experiment with forest governance. Simply monitoring the dynamics of the forest canopy is a significant technical challenge. However, this pales in comparison to the difficulties inherent in explaining those dynamics and assessing the sustainability and equity of different management regimes. Of the forests considered in the study, those where the Malagasy state has partnered with international conservation and development organizations seem to stand out, both in terms of stabilized, or even growing, forest cover, as well as a balance of interests among users. 相似文献
20.
中原地区不同植被类型花粉组合特征及对周围植被的代表性 总被引：1，自引：0，他引：1
中原地区落叶松林、阔叶杂木林、栎树林、油松阔叶混交林、竹林、柏树林、杨树林、河口草甸、农田花粉组合特征研究表明,森林植被花粉组合均以乔木花粉为主(占50%以上),平原区杨树林、河口草甸和农田均以草本花粉为主(占84%以上),均较好地反映了样点周围植被特征。松树林松树花粉高于70%,周围有少量松树的样点松树花粉占50%左右,周围没有松树的样点松树花粉在30%以下。落叶松林中落叶松花粉仅占2.4%,杨树林样品中未发现杨树花粉,竹林样品中禾本科花粉仅占3.4%,表明落叶松、杨树、禾本科花粉均具低代表性;判别分析也表明落叶松和杨树花粉呈低代表性。受周围和区域性植被影响,农田样点农作物花粉占30%左右,说明农田环境不利于花粉保存,故花粉浓度较其他植被类型低。 相似文献