共查询到20条相似文献，搜索用时 15 毫秒
1.
S. ROBERT AIKEN 《Geographical review》2004,94(1):55-79
ABSTRACT. Fires on Sumatra and Kalimantan have taken a heavy toll on Indonesia' remaining tropical forests. Drought exacerbates the fire hazard, but it does not cause the fires, most of which have been the result of inappropriate land‐use policies and practices. Peatland fires have emitted vast quantities of smoke that periodically blanket large parts of insular Southeast Asia, impairing visibility, disrupting travel, hampering economic activity, and posing serious health risks. The development agenda of Indonesia' New Order regime paid scant attention to forest management, including the need to detect, control, and suppress unwanted fires. 相似文献
2.
Livelihoods, fire and policy in eastern Indonesia 总被引：2，自引：0，他引：2
Indonesian legislation calls for a zero-burning policy. This approach to fire management is largely in response to significant negative impacts on the economy and the environment, not only in Indonesia but also the neighbouring region, that result annually from peat fires in Kalimantan and Sumatra. In this context, the present paper investigates the local use and management of fire in Flores and Sumba islands in eastern Indonesia. Our appraisals show that people's livelihoods depend on fire to maintain grasslands and, therefore, that the national policy and legislation for zero-burning is inappropriate and needs to be revised. This follows from the fact that not all fires cause damage and are unwanted. Through a series of rapid rural appraisal interviews, we found that the fires in grasslands are often lit intentionally to maintain the grasslands that local people use to sustain a variety of livelihood activities such as cattle rearing, hunting and farming. Although fires can damage or destroy remnant dry forests in eastern Indonesia, in order to be effective, future policy formulations need to account for this human livelihood dimension and the geographic variation in fuels, climate and land use. 相似文献
3.
"泥炭气候成因说"的探讨 总被引：2，自引：2，他引：2
文章从沼泽有机质积累的本质和泥炭的定义出发,通过对地带性气侯与沼泽小气候、泥炭的现状分布与自然分布、“没有泥炭分布”地区与“不能形成泥炭”地区、地区差异与地带性分异规律等几对矛盾在泥炭形成与分布中的作用和地位的详细剖析,认为：各种地带性气候条件下都能因为地表积水而形成湿地小气候,不同地带内湿地小气候都具有湿润的特征；泥炭沼泽的形成与分布主要是与湿地小气候及积水厌氧环境有关,用与泥炭形成没有直接联系的地带性气候指标来研究泥炭形成与分布的规律性是不合逻辑的；地带性的水热条件主要对泥炭在不同地带的分布面积起到一定的控制作用；泥炭现状分布因为人类活动的影响已不是自然规律的表现,从不能反映泥炭形成与分布自然状况的泥炭现状分布来分析泥炭形成与分布的自然规律,显然也不能得出正确的结论；“没有泥炭分布”的地区并不是因为这里的水热条件组合不能形成泥炭,各自然地带内都可形成泥炭且所有地带内的泥炭特征都是相似的,没有必要将它们区别对待,这些事实说明“泥炭气候成因说”对泥炭形成与分布的规律性的解释是不合逻辑的,泥炭的分布不具有地带性的规律。 相似文献
4.
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
5.
随着全球变暖的日益显著,气候变化及其影响越来越受到广泛关注。火干扰作为森林生态系统碳循环的一个重要组成部分,其干扰过程是对碳的再分配过程,因而对区域乃至全球的碳循环产生重要影响。气候变化、火干扰与生态系统碳循环三者之间存在因果循环关系,正确认识气候变化与火干扰的复杂关系及双向反馈作用,以及火干扰在生态系统碳循环中的作用,这对制定科学合理的火干扰管理策略,提高生态系统管理水平,减少碳排放,促进碳增汇,减缓全球变化速率均有重要意义。从两个方面阐述了气候变化、火干扰与生态系统碳循环之间的交互作用关系：气候变化与火干扰相互影响关系及双向反馈作用,分别从气候变化对火干扰的影响及火干扰对气候变化的影响两个方面阐述了两者之间的相互影响关系;火干扰与森林生态系统碳循环的交互作用,分别从火干扰对森林生态系统碳循环的影响及模型方法在模拟火干扰对森林生态系统碳循环影响中的应用两个方面论述火干扰对森林生态系统碳循环的影响及其定量评价模型方法。目前火干扰直接碳排放的模型方法比较完善,而间接影响碳循环的模型方法并不成熟,许多方法局限于定性描述,因此,应进一步探讨集成实地测量、遥感观测和模型模拟的跨尺度火干扰对碳循环的影响研究,注重尺度的转换问题。最后,提出了气候变暖背景下火干扰管理的路径选择,以及对今后的研究方向进行了展望。 相似文献
6.
Amy Hessl Jennifer Miller James Kernan David Keenum Don McKenzie 《The Professional geographer》2007,59(1):87-104
Fire history studies have traditionally emphasized temporal rather than spatial properties of paleo‐fire regimes. In this study we compare four methods of mapping paleo‐fires in central Washington from binary point data: indicator kriging, inverse distance weighting, Thiessen polygons, and an expert approach. We evaluate the results of each mapping method using a test (validation) dataset and receiver operating characteristic plots. Interpolation methods perform well, but results vary with fire size and spatial pattern of points. Though all methods involve some subjectivity, automated interpolation methods perform well, are replicable, and can be applied across varying landscapes. 相似文献
7.
Rehabilitating Upland Swamps Using Environmental Histories: A Case Study of the Blue Mountains Peat Swamps,Eastern Australia 
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下载免费PDF全文 Benjamin L. Freidman Kirstie A. Fryirs 《Geografiska Annaler: Series A, Physical Geography》2015,97(2):337-353
In response to peatland degradation by human activities worldwide, restoration through gully blocking is now being implemented in an attempt to return valuable ecological and hydrological services to degraded systems. Re‐establishing these services requires an understanding of how systems have formed and evolved in order to establish conditions that assist with physical and ecological recovery. However, management of peatlands and swamps continues without prior investigation into the environmental history of these ecosystems. This study investigates stratigraphy, sediment ages and peat forming potential within three Temperate Highland Peat Swamps on Sandstone in the Blue Mountains, NSW. These swamps are listed as Endangered Ecological Communities under the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) and the Threatened Species Conservation Act 1995 (NSW). High discontinuity in sediment structure, peat forming potential and timeframes of swamp initiation were observed across the three swamps. This localised variation reflects the complex geomorphic processes acting within and between these systems. Such data provides scientists and managers with key indicators to assess timeframes over which infilling, vegetation establishment and peat formation occurs. These tools can guide prioritisation, conservation and financial expenditure for the management and rehabilitation of temperate peat swamps. 相似文献
8.
大兴安岭泥炭微量元素分布特征及其环境意义 总被引：6，自引：4，他引：6
采用原子吸收光谱和等离子体发射光谱等现代仪器分析方法对大兴安泥炭生趣剖面中Ｃｕ，Ｐｂ，Ｚｎ，Ｃｄ，Ｈｇ，Ｃｒ，Ｎｉ，Ｍｎ，Ｓｒ，Ｂａ等１２种微量元素进行了测定，结果表明，大兴安岭地区古莲，图强泥炭地和同一泥炭地沼泽泥炭发育的不同阶段，微量元素含量分布规律不十分明显，与俄国斯典型同类泥炭相比，Ｍｎ含量俄罗斯泥炭明显高于大兴安岭泥炭，Ｚｎ，Ｃｏ，Ｂ含量大兴安岭泥炭明显高于俄罗期泥炭。 相似文献
9.
We investigated the role of fire in controlling bush thickening in arid savannas. Three controlled fires were initiated to investigate the responses of planted seedlings, saplings and mature shrubs. The stem diameters of seedlings, saplings and mature shrubs prior to the fire were measured. Other dimensions of the saplings and mature shrubs such as leaf mass were also estimated. The intensity of each fire was estimated. Fire temperatures adjacent to seedlings saplings and mature shrubs were measured using fire paints on steel plates. All three fires were moderately hot. One year after each fire, the mortality of seedlings in the fire treatments was very high (97.1–99.3%) and significantly greater than in adjacent controls (16.1–51.6%). Mortality and topkill of saplings and mature shrubs were negatively related to stem diameter. Fire temperature did not significantly affect mortality and topkill in most cases. Surviving saplings showed a much greater resprout response, relative to pre fire size, than larger shrubs and trees. Our results suggest that fire is crucial in interrupting the transition from open grassy savanna to thicket in arid savannas. Managers who prevent fires at this stage are likely to experience bush thickening in the future. 相似文献
10.
Coal fires occur in underground natural coal seams, in exposed surface seams, and in coal storage or waste piles. The fires ignite through spontaneous combustion or natural or anthropogenic causes. They are reported from China, India, USA, South Africa, Australia, and Russia, as well as many other countries. Coal fires lead to loss of a valuable resource (coal), the emission of greenhouse-relevant and toxic gases, and vegetation deterioration. A dangerous aspect of the fires is the threat to local mines, industries, and settlements through the volume loss underground. Surface collapse in coal fire areas is common. Thus, coal fires are significantly affecting the evolution of the landscape. Based on more than a decade of experience with in situ mapping of coal fire areas worldwide, a general classification system for coal fires is presented. Furthermore, coal seam fire geomorphology is explained in detail. The major landforms associated with, and induced by, these fires are presented. The landforms include manifestations resulting from bedrock surface fracturing, such as fissures, cracks, funnels, vents, and sponges. Further manifestations resulting from surface bedrock subsidence include sinkholes, trenches, depressions, partial surface subsidence, large surface subsidence, and slides. Additional geomorphologic coal fire manifestations include exposed ash layers, pyrometamorphic rocks, and fumarolic minerals. The origin, evolution, and possible future development of these features are explained, and examples from in situ surveys, as well as from high-resolution satellite data analyses, are presented. The geomorphology of coal fires has not been presented in a systematic manner. Knowledge of coal fire geomorphology enables the detection of underground coal fires based on distinct surface manifestations. Furthermore, it allows judgments about the safety of coal fire-affected terrain. Additionally, geomorphologic features are indicators of the burning stage of fires. Finally, coal fire geomorphology helps to explain landscape features whose occurrence would otherwise not be understood. Although coal fire-induced thermal anomalies and gas release are also indications of coal fire activity, as addressed by many investigators, no assessment is complete without sound geomorphologic mapping of the fire-induced geomorphologic features. 相似文献
11.
MM Cruickshank RW TomlinsonD BondPM DevineCJW Edwards 《Applied geography (Sevenoaks, England)》1995,15(4)
Northern Ireland has a tradition of peat cutting; 78 per cent by area of remaining lowland bogs and 46 per cent of blanket bogs have been cut in the past. Since the early 1980s, machine peat extraction for fuel and horticulture has increased, against a background of changing economic support for agriculture, high rural unemployment and agricultural underemployment. Cutting fuel peat can reduce household fuel costs and some peat fuel is sold to gain income. Horticultural peat is cut mainly for sale. Expansion of machine extraction, with possible environmental impacts, occurred as interest in peatland conservation increased. Potential conflict arises between local economic needs and conservation. Machine cutting for fuel is widespread, but affects only 2.6 per cent of the blanket peat area; horticultural extraction is more localized and is only one-fifth of the extent of fuel extraction. Altitude, distance from roads, land ownership and rights, turbary, religious affiliation, local economic needs and the role of government departments all contribute to explaining the distribution and extent of extraction. 相似文献
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Fire is an important disturbance agent for terrestrial ecosystems, particularly in tropical and subtropical regions where its occurrence is controlled by multiple biophysical and anthropogenic variables. We assessed the temporal and spatial patterns of active fire detections (MODIS product MCD14ML) in the Caribbean region of Colombia between 2003 and 2015, using time series, cross-correlation, hot spot and density techniques. We also assessed the environmental envelope of active fires by evaluating the effect of multiple biophysical and anthropogenic variables on fire presence/absence using generalized linear models (GLMs). Results show that fires follow a clear intra-annual cycle, with 86% of fire events taking place during the region's main dry season (December–March). There is also inter-annual variability related to the Tropical North Atlantic (TNA) quasi-decadal climatic oscillation. Active fires exhibit a distinctive spatial pattern, with regional hotspots. The set of variables that best explain fire presence/absence include biophysical (TNA, temperature annual range, dry quarter precipitation), anthropogenic (minimum distance to towns and roads) and composite (NDVI) variables. The extensive and ongoing land cover transformation of this region, from forest to pasture and agriculture, will likely increase the extent of burned areas and future carbon fire emissions to the atmosphere. 相似文献
15.
The northern and eastern sides of the Cuilcagh Mountain upland, in northwest Ireland, are mantled with over 50 km2 of blanket bog that has experienced an unusually high spatial and temporal frequency of peat mass movements. In all, 29 peaty-debris slides, nine bog slides, two peat slides and five more peat landslides of uncertain type have been recorded within this study area. More than 27 km2 of this peatland has been afforded several levels of statutory protection as well as international recognition of its geo-environmental importance. Field and laboratory investigations of the peat at several of the more recent failure sites showed it to be typical of Irish and Pennine (northern England) blanket bogs in most physical and hydrological respects. Field geomorphological evidence and modelling of stability thresholds indicate that the particular susceptibility of the Cuilcagh Mountain blanket bog to failure arises from two local factors: (i) the attainment of threshold maximum peat depths on the East Cuilcagh plateau, and (ii) the unconformable deposition of thin layers of glacial till (in places) and blanket peat over the pre-existing topographic surface formed from the major shale formations that underlie the northern slopes. With two exceptions, there is no conclusive evidence that human activities and management strategies for the area have had any significant influence on the occurrence of the peat landslides. The high frequency of large rainfall events since 1961 that did not trigger landslides suggests that failures are unlikely to become more frequent in response to climate change effects because they are controlled by slowly changing internal thresholds. 相似文献
16.
《Geography and Natural Resources》2008,29(2):150-155
A study is made of the behavior of artificial radionuclides and heavy metals during a forest fire. It is shown that forest fires are accompanied by airborne migration of some heavy metals and artificial radionucleides as well as by pollution of new areas. The main depositories of elements falling out of the atmosphere are provided by forest litter, mosses, lichens, and tree needles. Up to 40% of 137Cs and 90Sr can migrate from the sites of fires, which originally were contained in the soil-vegetation cover. The elements that are carried away from the sites of fires partly deposit themselves on adjacent areas. 相似文献
17.
Community and Social Capital in Upper-Income Neighborhoods: An Investigation in Metropolitan Phoenix
《Urban geography》2013,34(8):1065-1079
This study investigates how upper-income residents respond to neoliberal practices and private governance in forming unusual community relationships in landscapes seemingly devoid of traditional social capital. Based on field work in three communities in metropolitan Phoenix, it was concluded that through private groups and an intrinsic nature to know others, residents create meaningful relationships at scales other than the neighborhood or municipality and focus on nontraditional, privatized community institutions. Whereas these new relationships enhance residents' feelings of connectedness, they generally promote bonding over bridging social capital. Moreover, the draconian effects homeowners or property owners' associations have on normative landscape and behavioral constraints tend to wane considerably as the transition from the developer's idea of place and the residents' vision of place occurs temporally. 相似文献
18.
Glen E. Liston Oddbjørn Bruland Jan-Gunnar Winther Hallgeir Elvehøy Knut Sand 《Polar research》1999,18(2):283-290
In the near coastal regions of Dronning Maud Land, Antarctica, below-surface ice-melt in blue-ice areas has been observed. The low scattering coefficients of the large-grained blue-ice allow penetration of solar radiation, thus providing an energy source below the ice surface. The sub-surface meltwater is significant enough to show up on remote-sensing imagery in the form of ice-covered lakes. Adjacent snow-accumulation areas have much higher scattering coefficients and consequently limit solar radiation penetration in these regions. These snow and ice surfaces are generally below freezing, and little surface melting occurs. To assess the response of these melt features to changes in atmospheric forcings such as cloudiness, air temperature, and snow accumulation, a physically-based model of the coupled atmosphere, radiation, snow, and blue-ice system has been developed. The model consists of a heat transfer equation with a spectrally-dependent solar-radiation source term. The penetration of radiation into the snow and blue-ice depends on the surface albedo, and the snow and blue-ice grain size and density. Model simulations show that ice melt occurring in this area is sensitive to potential variations in atmospheric forcing. Under certain conditions more traditional surface melting occurs and, under other conditions, the existing melt processes can be shut down completely. In light of the sensitivity of this system to variations in atmospheric forcing, and the ability to view melt-related features using remote sensing, a tool exists to efficiently monitor variations in Antarctic coastal climate. 相似文献
19.
E. I. Ponomarev 《Geography and Natural Resources》2011,32(1):72-75
The technology that has been developed for real-time analysis of the lightning-caused forest fire risks is discussed. Comparative
estimates of the number and areas of such fires are obtained for Russia’s regions. The zone of localization of lightning-caused
fires is identified through the use of the GIS capabilities. 相似文献
20.
荒漠-绿洲区是干旱区地表景观格局变化最频繁的地区,深入研究荒漠-绿洲区不同景观格局土壤环境的差异对揭示干旱区生态系统过程至关重要。本研究通过采集石羊河流域荒漠、过渡带和绿洲土壤样品,综合运用多种分析方法,研究荒漠-绿洲区不同景观格局土壤理化属性的差异及其相互作用关系。结果表明：从荒漠、过渡带到绿洲景观,土壤质地和持水性能在不断好转,酸碱度和盐分状况变化不大,养分状况则表现为荒漠和过渡带具有近乎相同的有机碳和全氮含量,绿洲具有显著增加的有机碳、全氮和全磷含量。在不同深度上,荒漠景观土壤理化属性几乎没有变化;过渡带土壤质地由表层至深层不断改善,含水量逐层增大,全磷含量缓慢增加,C∶N和C∶P的值波动减小;绿洲景观土壤含水量由表层至深层显著增加,养分含量显著降低,C∶N和C∶P的值显著减小。总体而言,荒漠景观土壤理化属性的分异程度最小,绿洲景观分异程度最大,过渡带景观在土壤质地和含水量方面的分异程度较大,在土壤养分方面的分异程度较小。此外,过渡带景观土壤理化属性的自相关程度最高,且土壤质地是引起其他土壤理化属性分异的主要原因。 相似文献