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1.
Natural Hazards - Forest fires are one of the major environmental problems that cause harmful economic and ecological damage. The Algerian forest and in particular the Tlemcen forest massif where... 相似文献
2.
干旱气候因子与森林火灾 总被引：5，自引：0，他引：5
森林火灾作为一种自然灾害, 气候变化直接或间接影响森林燃烧的火环境, 进而对火发生和火行为产生影响. 干旱气候条件与森林火灾的发生有密切的关系, 气象条件通过气温、 日照、 蒸发量、 风力、 空气湿度等影响着森林火灾的发生和发展. 一般情况下, 气温高、 降水少、 湿度小、 风力大易发生森林火灾. 在山区, 山谷风和地形影响森林火灾蔓延, 森林火灾的蔓延主要受山谷风所控制, 具有间歇性, 另外地形的变化在很大程度上制约着火势的蔓延. 所以, 要利用不同时段的气象条件、 山风出现的时间及有利地形, 及时组织灭火和控制火势蔓延. 森林火灾的发生有各种类型, 通过对森林火灾中一些特殊火行为及相关元素对火灾发展蔓延影响分析, 找出森林火灾扑救与逃生的方法及注意事项. 相似文献
3.
以云南阳宗海1020 cm长的湖泊沉积物岩芯为研究对象,由7个木屑和树叶残体样的AMS14C测年建立岩芯年代框架,以18~19 cm间隔获取52个样品作花粉/炭屑分析,重建了阳宗海流域过去13000年的植被、气候以及森林火灾历史。研究结果表明,过去13000年植被演替、气候变化和森林火灾可分为5个阶段:1)13200~11000 cal.a B.P.,植被以常绿、落叶阔叶混交林为主,气候温凉湿润,森林火灾多发,后期(12300~11000 cal.a B.P.)随着温度和湿度的降低,森林火灾发生愈加频繁;2)11000~8000 cal.a B.P.,松林扩张,阔叶林缩小,气候较上阶段温暖偏干,森林火灾发生次数明显降低;3)8000~5000 cal.a B.P.,松林和常绿阔叶林占优势,且出现暖热性的枫香林,流域内气温升至13000 cal.a B.P.以来的最高值,湿度进一步降低,但森林火灾发生频率低;4)5000~800 cal.a B.P.,松林扩张至最盛,常绿阔叶林收缩,落叶阔叶林成分增加,气温和湿度均明显下降,森林火灾发生频率有所增加;5)800 cal.a B.P.至今,松林和常绿阔叶林收缩,落叶阔叶成分增加,草本植物中禾本科迅速上升,可能与人类活动有关,森林火灾发生频率低。阳宗海花粉/炭屑记录重建的植被、气候和森林火灾史表明,在滇中地区,落叶阔叶成分易引起森林火灾,冷气候导致多发的森林火灾,冷干气候是宜森林火灾发生的气候条件。 相似文献
4.
The study examines the synoptic situations and weather conditions under which occurred Israel's largest forest fires between
the years 1987–1995. Annual rainfall and maximum temperature were found to have a positive correlation with both the size
of the burnt area and the frequency of fires. A negative correlation was found for the relative humidity at 12 UTC for the
same parameters. The fire season in Israel starts in May and ends in November, the peak months being May, June and July. No
large fires were observed during the rainy season, December–February, despite the relatively low precipitation characterizing
the region. Atmospheric disturbances as well as quasi-stationary systems were found to be favorable for the development of
forest fires in Israel: the North African (‘Sharav’) cyclone and the Red Sea trough, which are common during spring and autumn.
These systems carry hot, dry air from the deserts and are responsible for 55% of the burnt area from major forest fires in
Israel and up to 33% of the major forest fires. Sixty-five percent of the forest fires occurred during the summer all of them
under the quasi-stationary system of the Persian Gulf trough. These fires did not spread as widely as those that occurred
under the North African cyclone and the Red Sea trough systems. The role of weather in the propagation of fire is exemplified
in the case study of the ‘Sha'ar ha Gai’ fire of July 1995 — the biggest forest fire in the history of Israel (1300 ha).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Holocene colluvial chronology in a sub‐arctic esker landscape at Kuttanen,Finnish Lapland: kettleholes as geo‐ecological archives of interactions amongst fire,vegetation, soil,climate and geomorphological instability 
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下载免费PDF全文 John A. Matthews Matti Seppälä 《Boreas: An International Journal of Quaternary Research》2015,44(2):343-367
Excavations were made in the colluvial deposits of seven kettleholes in a sandy esker at Kuttanen, northwestern Finnish Lapland. The Holocene history of forest fires and the associated colluvial activity initiated on the slopes of the kettleholes were reconstructed based on 131 radiocarbon dates from charcoal layers. These dates were supplemented by luminescence dating of colluvial sand layers. The first forest fires occurred ～9000 years ago following the immigration of Pinus sylvestris about 1000 years after deglaciation. Evidence of forest fires and colluvial activity increased with the density of the pine forest, reaching a maximum during the Holocene Thermal Maximum between ～8000 and 4000 cal. a BP, declining thereafter to a minimum in the last ～500 years. This multimillennial‐scale pattern corresponds with forest fires being triggered by lightning strikes during the warmest summer weather of the Holocene, which also produced heavy rain and slope wash from convective storms. The 50 forest fires identified over the Holocene indicate a long cycle in fire frequency of 1 in ～200 years, which appears to reflect the average successional recovery time of the forest. Complex interactions amongst vegetation, fire and climate may account for little or no association between 23 centennial‐ to millennial‐scale clusters of forest fires/colluvial events and Holocene temperature or precipitation anomalies. Buried podzols indicate five phases of soil formation and hence low levels of landscape disturbance. The kettleholes and their colluvial deposits therefore provide a unique geo‐ecological archive that has led to new insights into the geo‐ecological interactions that affect environmental change in the sub‐arctic landscape. 相似文献
6.
Importance of climate,forest fires and human population size in the Holocene boreal forest composition change in northern Europe 下载免费PDF全文
下载免费PDF全文 Niina Kuosmanen Heikki Seppä Teija Alenius Richard H. W. Bradshaw Jennifer l. Clear Ludmila Filimonova Maija Heikkilä Hans Renssen Miikka Tallavaara Triin Reitalu 《Boreas: An International Journal of Quaternary Research》2016,45(4):688-702
The relative importance of climate, forest fires and human population size on long‐term boreal forest composition were statistically investigated at regional and local scales in Fennoscandia. We employ pollen data from lakes, reflecting regional vegetation, and small forest hollows, reflecting local vegetation, from Russia, Finland and Sweden to reconstruct the long‐term forest composition. As potential drivers of the Holocene forest dynamics we consider climate, generated from a climate model and oxygen isotope data, past forest fires generated from sedimentary charcoal data and human population size derived from radiocarbon dated archaeological findings. We apply the statistical method of variation partitioning to assess the relative importance of these environmental variables on long‐term boreal forest composition. The results show that climate is the main driver of the changes in Holocene boreal forest composition at the regional scale. However, at the local scale the role of climate is relatively small. In general, the importance of forest fires is low both at regional and local scales. The fact that both climate and forest fires explain relatively small proportions of variation in long‐term boreal vegetation in small forest hollow records demonstrates the complexity of factors affecting stand‐scale forest dynamics. The relative importance of human population size was low in both the prehistorical and the historical time periods. However, this is the first time that this type of data has been used to statistically assess the importance of human population size on boreal vegetation and the spatial representativeness of the data may cause bias to the analysis. 相似文献
7.
森林大火对冻土环境影响的研究进展 总被引：2，自引：2，他引：0
森林大火是森林生态系统最主要的干扰因素之一,不仅影响着森林生态系统内部的营养物质循环、水分和能量流动、土壤理化性质的变化,而且对冻土环境和冷生土壤和土壤碳库、碳氮循环等生物地球化学过程有着重要影响。随着气候变暖和人为活动不断增强,北方林区火灾日益频繁,对冻土的水热影响显著：活动层加深、薄层冻土退化、浅层有机碳大量快速释放、森林和湿地的逆向演替,导致热融沉陷、滑塌、泥石流等现象发生。通过综述国内外森林大火对冻土环境影响的研究进展,分析指出目前森林大火对冻土环境影响的研究主要集中在火烧之后短时间、小范围的定性描述与推断,缺乏长时间、大范围的定量分析。尤其是在大兴安岭地区,除了20世纪90年代初期的少量研究外,此后这方面研究虽有零星报道,但缺乏长期和系统的观测与模型研究,所以森林大火对冻土环境的研究,可以利用空间代替时间的方法,通过长、短期的野外观测和数值模拟相结合,定量研究森林大火之后,多年冻土的水热状态、过程和变化机制,可以为寒区林区、湿地保护、生态环境修复提供科学依据。 相似文献
8.
Cox Robin S. Hill Tiffany T. Plush Tamara Heykoop Cheryl Tremblay Crystal 《Natural Hazards》2019,96(1):213-224
Fire has become one of the main disturbances in terrestrial ecosystems worldwide. It is known that elevation influences the occurrence of fire events; however, this variable has been poorly studied, although it is of particularly relevance to the Mexican topography. The objective of this research was to analyze the altitudinal distribution of forest fires in Mexico over a period of 11 years. Elevation gradients were defined based on a Digital Elevation Model and the main ecoregions of the country: (1) shrubland and tropical forests (0–1000 masl), (2) grasslands (1001–2000 masl) and (3) temperate forests (>?2000 masl). Each ecoregion was divided into Climate Research Units and the number of fires per unit was quantified. The G Getis–Ord statistic was applied in order to define the spatial patterns presented by the fire events. A relationship between the occurrence of fires and the El Niño Southern Oscillation phenomenon was also determined through a Pearson correlation. The results showed that the occurrence of fire events presented variability along elevation gradients, with elevation a determining factor in their occurrence. Gradient 3, with the highest elevation, had the greatest number of fires and also presented the largest area of fire event clustering. These results contribute to the knowledge of the spatial distribution of forest fires in Mexico and are of value to appropriate decision-making for effective fire management.
相似文献9.
Nives Grasso Andrea Maria Lingua Maria Angela Musci Francesca Noardo Marco Piras 《Natural Hazards》2018,90(2):623-637
Every year, there are almost 50,000 forest fires in Europe (127/day), which have burned an area equal to more than 450,000 ha. An effective management of forest fires is therefore fundamental in order to reduce the number of the fires and, especially, the related burned areas, preserving the environment and saving human lives. However, some problems still exist in the structure of information and in the harmonization of data and fire management procedures among different European countries. Pursuing the same interoperability aims, the European Union has invested in the development of the INSPIRE Directive (Infrastructure for Spatial Information in Europe) to support environmental policies. Furthermore, the EU (European Union) is currently working on developing ad hoc infrastructures for the safe management of forests and fires. Moving from this premises and following an analysis of the state of the art of information systems for forest fire-fighting, in the light of the end-user requirements, the paper presents the INSPIRE—compliant design of a geographical information system, implemented using open-source platforms. 相似文献
10.
《地学前缘(英文版)》2020,11(4):1203-1217
Natural hazards are often studied in isolation.However,there is a great need to examine hazards holistically to better manage the complex of threats found in any region.Many regions of the world have complex hazard landscapes wherein risk from individual and/or multiple extreme events is omnipresent.Extensive parts of Iran experience a complex array of natural hazards-floods,earthquakes,landslides,forest fires,subsidence,and drought.The effectiveness of risk mitigation is in part a function of whether the complex of hazards can be collectively considered,visualized,and evaluated.This study develops and tests individual and collective multihazard risk maps for floods,landslides,and forest fires to visualize the spatial distribution of risk in Fars Province,southern Iran.To do this,two well-known machine-learning algorithms-SVM and MARS-are used to predict the distribution of these events.Past floods,landslides,and forest fires were surveyed and mapped.The locations of occurrence of these events(individually and collectively) were randomly separated into training(70%) and testing(30%) data sets.The conditioning factors(for floods,landslides,and forest fires) employed to model the risk distributions are aspect,elevation,drainage density,distance from faults,geology,LULC,profile curvature,annual mean rainfall,plan curvature,distance from man-made residential structures,distance from nearest river,distance from nearest road,slope gradient,soil types,mean annual temperature,and TWI.The outputs of the two models were assessed using receiver-operating-characteristic(ROC) curves,true-skill statistics(TSS),and the correlation and deviance values from each models for each hazard.The areas-under-the-curves(AUC) for the MARS model prediction were 76.0%,91.2%,and 90.1% for floods,landslides,and forest fires,respectively.Similarly,the AUCs for the SVM model were 75.5%,89.0%,and 91.5%.The TSS reveals that the MARS model was better able to predict landslide risk,but was less able to predict flood-risk patterns and forest-fire risk.Finally,the combination of flood,forest fire,and landslide risk maps yielded a multi-hazard susceptibility map for the province.The better predictive model indicated that 52.3% of the province was at-risk for at least one of these hazards.This multi-hazard map may yield valuable insight for land-use planning,sustainable development of infrastructure,and also integrated watershed management in Fars Province. 相似文献
11.
The spatial and temporal distribution of forest fires displays a complex pattern which strongly influences the forest landscape and the neighbouring anthropogenic development. Statistical methods developed for spatio-temporal stochastic point processes can be employed to find a structure, detect over-densities and trends in forest fire risk and address towards prevention and forecasting measures. The present study considers the Portuguese mapped burnt areas official geodatabase resulting from interpreted satellite measurements, covering the period 1990–2013. The main goal is to detect whether space and time act independently or whether, conversely, neighbouring events are also closer in time, interacting to generate clusters. To this purpose, the following statistical methods were applied: (1) the geographically weighted summary statistics, to explore how the average burned area vary locally through the investigated region; (2) the bivariate K-function, to test the space–time interaction and the spatial attraction/independency between fires of different size; and (3) the space–time kernel density, allowing elaborating smoothed density surfaces and representing over-densities of large versus medium versus small fires and on north versus south region. The proposed approach successfully allowed finding and mapping spatio-temporal patterns within this large data series. Specifically, medium fires tend to aggregate around small fires, while large fires aggregate at a larger distance and longer times, indicating that the return time following these events is longer than for small and medium fires. The density maps shows that hot spots are present almost each year in the northern region, with a higher concentration in the northern areas, while the southern half of the country counts lower surface densities of fires, which are mainly concentrated in the central period (2000–2007). 相似文献
12.
Continuous and campaign-based aerosol field measurements are essential in understanding fundamental atmospheric aerosol processes and for evaluating their effect on global climate, environment and human life. Synchronous measurements of Aerosol Optical Depth (AOD), Black Carbon (BC) aerosol mass concentration and aerosol particle size distribution were carried out during the campaign period at tropical urban regions of Hyderabad, India. Daily satellite datasets of DMSP-OLS were processed for night-time forest fires over the Indian region in order to understand the additional sources (forest fires) of aerosol. The higher values in black carbon aerosol mass concentration and aerosol optical depth correlated well with forest fires occurring over the region. Ozone Monitoring Instrument (OMI) aerosol index (AI) variations showed absorbing aerosols over the region and correlated with ground measurements. 相似文献
13.
Natural Hazards - We study the prevalence of forest fires in Spain in the long run by computing the probability that a forest tree, as opposed to shrub or bush, will be lost to fire over the course... 相似文献
14.
Rampant pasture burning has lead to various forest fires taking their toll over the health of many forests. Nanda Devi Biosphere Reserve, located in the northern part of India, witnessed a majority of these incidents in the recent past, though, it remains comprehensively untouched from research studies. The scale of these wildfires has led to an immense requirement of preventive measures to be taken for recuperating from such events. This requires for an in-depth analysis of the study area, its history of wildfires and their causes. These efforts would assist in laying a blueprint for a contingency plan in the event of a wildfire. This work proposes an evolutionary optimized gradient boosted decision trees for preparing wildfire susceptibility maps for the study area that would aid in the government’s forest preservation and disaster management activities. The study took 18 ignition factors of elevation, slope, aspect, plan curvature, topographic position index, topographic water index, normalized difference vegetation index, soil texture, temperature, rainfall, aridity index, potential evapotranspiration, relative humidity, wind speed, land cover and distance from roads, rivers and habitations into consideration. The study revealed that approximately 1432.025 km2 of area was very highly susceptible to forest fires while 1202.356 km2 was highly susceptible to forest fires. The proposed model was compared against various machine learning models such as random forest, neural networks and support vector machines, and it outperformed them by achieving an overall accuracy of 95.5%. The proposed model demonstrated good prospects for application in the field of hazard susceptibility mappings. 相似文献
15.
Landslides - Increasing number of landslides occurred in the cold regions over the past decades due to rising temperature or forest fires associated with climate change. The instability of thawing... 相似文献
16.
Mineralogy and Petrology - Natural disasters such as forest fires can result in extensive and costly property damage. These events may be the result of a human error or system failure triggered by... 相似文献
17.
Disconnected policies and actors and the missing role of spatial planning throughout the risk management cycle 总被引：2，自引：2，他引：0
Kalliopi Sapountzaki Sylvia Wanczura Gabriella Casertano Stefan Greiving Gavriil Xanthopoulos Floriana F. Ferrara 《Natural Hazards》2011,59(3):1445-1474
The present work addresses the problem of lack of coordination between policies and actors with joint competence for risk
management, i.e., civil protection, spatial planning, and sectoral planning (e.g., forest policy in the case of forest fire
risk). Spatial planning in particular is assigned a minor or no role at all though it might perfectly operate as the coordinating
policy platform; the reason is that spatially relevant analysis and policy guidance is an omnipresent component of the risk
management cycle. However, disconnected risk relevant policies turning a blind eye to spatial planning might cause several
adverse repercussions: Breaks in the response-preparedness-prevention-remediation chain (which should function as a continuum),
minimal attention to prevention, risk expansion and growth instead of mitigation, lack of synergies between involved actors
as well as duplicated or even diverging measures and funding. The authors bear witness to the above suggestions by examining
three cases of European (regional and local) risk management systems faced with failures when confronting natural hazards
(floods and forest fires). These three systems are embedded in different types of political-administrative structures, namely
those of the city of Dortmund (Germany) facing floods, Eastern Attica region (Greece), and Lazio Region (Italy) facing forest
fires. 相似文献
18.
The paucity of low- and middle-elevation paleoecologic records in the Northern Rocky Mountains limits our ability to assess current environmental change in light of past conditions. A 10,500-yr-long vegetation, fire and climate history from Lower Decker Lake in the Sawtooth Range provides information from a new region. Initial forests dominated by pine and Douglas-fir were replaced by open Douglas-fir forest at 8420 cal yr BP, marking the onset of warmer conditions than present. Presence of closed Douglas-fir forest between 6000 and 2650 cal yr BP suggests heightened summer drought in the middle Holocene. Closed lodgepole pine forest developed at 2650 cal yr BP and fires became more frequent after 1450 cal yr BP. This shift from Douglas-fir to lodgepole pine forest was probably facilitated by a combination of cooler summers, cold winters, and more severe fires than before. Five drought episodes, including those at 8200 cal yr BP and during the Medieval Climate Anomaly, were registered by brief intervals of lodgepole pine decline, an increase in fire activity, and mistletoe infestation. The importance of a Holocene perspective when assessing the historical range of variability is illustrated by the striking difference between the modern forest and that which existed 3000 yr ago. 相似文献
19.
C SUDHAKAR REDDY V V L PADMA ALEKHYA K R L SARANYA K ATHIRA C S JHA P G DIWAKAR V K DADHWAL 《Journal of Earth System Science》2017,126(1):11
Carbon emissions released from forest fires have been identified as an environmental issue in the context of global warming. This study provides data on spatial and temporal patterns of fire incidences, burnt area and carbon emissions covering natural vegetation types (forest, scrub and grassland) and Protected Areas of India. The total area affected by fire in the forest, scrub and grasslands have been estimated as 48765.45, 6540.97 and 1821.33 km 2, respectively, in 2014 using Resourcesat-2 AWiFS data. The total CO 2 emissions from fires of these vegetation types in India were estimated to be 98.11 Tg during 2014. The highest emissions were caused by dry deciduous forests, followed by moist deciduous forests. The fire season typically occurs in February, March, April and May in different parts of India. Monthly CO 2 emissions from fires for different vegetation types have been calculated for February, March, April and May and estimated as 2.26, 33.53, 32.15 and 30.17 Tg, respectively. Protected Areas represent 11.46% of the total natural vegetation cover of India. Analysis of fire occurrences over a 10-year period with two types of sensor data, i.e., AWiFS and MODIS, have found fires in 281 (out of 614) Protected Areas of India. About 16.78 Tg of CO 2 emissions were estimated in Protected Areas in 2014. The natural vegetation types of Protected Areas have contributed for burnt area of 17.3% and CO 2 emissions of 17.1% as compared to total natural vegetation burnt area and emissions in India in 2014. 9.4% of the total vegetation in the Protected Areas was burnt in 2014. Our results suggest that Protected Areas have to be considered for strict fire management as an effective strategy for mitigating climate change and biodiversity conservation. 相似文献
20.
The charcoal discovery in the soils and sediments of the relic forest of Pinus nigra ssp Salzmanni near Saint-Guilhem-le-Désert allows us to establish a chronology of Holocene fires. Their origin dates from the Middle Holocene, but they are especially significant after the construction of the medieval abbey during the 9th century. The original pine plantation was heterogeneous, with another pine, Pinus sylvestris, which has now been eradicated. Changes in the fire modes have been observed, recent human fires being generalized, which resulted in a significant regression of the forest cover, which was replaced by box-tree formations. To cite this article: J.-L. Vernet et al., C. R. Geoscience 337 (2005). 相似文献