林火管理中的适度风险管理探讨

提出实现森林火灾减灾效益最大 ,必须在火生态评估的基础上区分两类性质不同的火。定义了林火风险价值、风险度、风险成本 ,及其所包含的内容和关系式。此系统具体数值的确定 ,可为防火资源的优化配置 ,火灾损失的预估及扑火力量的确定 ,扑火方案制定提供经济上的判据     

Evaluating the efficiency of the Dong model in determining fire vulnerability in Iran's Zagros forests

Recent fires in Iran's Zagros forests have inflicted heavy,extensive losses to the environment,forests,villages,and forest inhabitants,resulting in a huge financial loss to the country.With the increasing risk of fire and the resulting losses,it has become ever more necessary to design and develop efficient fire control and prediction procedures.The present study utilizes the Dong model to develop a map of areas vulnerable to fire in the Zarivar lake forests as a representative sample of Zagros forests.The model uses as its inputs some of the most significant factors(such as vegetation,physiographic features,and the human component) that affect the fire occurrence and spread.Having assigned weights to each factor based on the model,all maps were overlapped in the ArcMap and then the region was divided into five zones.The results showed that 74% of the region was located in three classes:highly vulnerable,vulnerable,and medially vulnerable.To validate the proposed zoning map it was compared with a map based on real data obtained from previous fires.The results showed that 81% of fire incidents were located in highly vulnerable,vulnerable and medially vulnerable zones.Furthermore,the findings indicated a medium to a high degree of fire vulnerability in Zarivar Lake forests.     

地中海沿岸主要国家林火管理综述及对我国的启示

森林火灾具有很强的突发性和破坏性,处置救援困难,是地中海沿岸国家最为严重的自然灾害之一。针对地中海沿岸地区森林火灾发生较为频繁,但由于积极应对,火灾实际造成的危害较小的主要国家,文中从火灾状况、火管理机构、防火措施以及民防机制等方面进行阐述,分析、总结地中海沿岸主要国家林火管理措施与经验,以期为我国林火研究、林火管理和防火灭火实践,特别是灾前积极预防、灾中安全扑救及灾后生态恢复等提供借鉴。     

我国森林火灾发生的时空规律研究

森林火灾对森林生态系统有重要影响,可能给森林生态系统带来毁灭性的损害,但在森林生态系统演替中又具有重要和积极的影响。研究森林火灾发生规律是森林火灾预测预报的基础,也是指导森林防火与补救工作的重要科学依据,具有重要的理论与现实意义。受气候变化等因素的影响,近年来森林火灾有多发的趋势,关于森林火灾发生及其生态影响成为研究的热点。文中在参考国外研究成果的基础上,从森林火灾发生的不同时间尺度和不同空间尺度上评述我国森林火灾发生的时空分布规律,总结我国森林火灾发生的一些总体规律性,指出现有研究存在的问题,并对未来的研究方向进行展望。     

Fuel types and crown fire potential in <Emphasis Type="Italic">Pinus halepensis</Emphasis> forests

There is a lack of knowledge to identify and classify forest structures according to the risk of crown fires, especially in Mediterranean regions. In this study, for the first time, we use real information, obtained after a wildfire that burnt under extreme meteorological conditions, to classify forest structures of Pinus halepensis into fuel types as a function of crown fire potential. We identified fourteen forest structures which characterize many forest types in Western Mediterranean areas depending on canopy closure, number of tree layers, percent of each tree layer and overall tree density. By using the pattern of fire types that burnt the most numerous forest structures, we have identified four fire hazard groups of forest structures which are considered different fuel types. The first two had the lowest risk of active crown fires and they differed in the proportion of surface fires and passive crown fires. The third fuel type was the threshold between structures with low and high extreme fire behavior; while the fourth had a high risk of active crown fires. Firefighters and forest managers who are demanding this kind of schema, will test and upgrade this classification of fuel types in function of crown fire potential during future wildfires.     

Modeling Mediterranean forest fuels by integrating field data and mapping tools

Fire behavior modeling systems are important in predicting wildfire risk, fire growth, and fire effects. However, simulation software requires a new fuel modeling to include fuel treatments, prescribed fire and the transition to crown fire. The thirteen Rothermel models are insufficient in completely representing Mediterranean ecosystems. In this sense, the new American modeling includes five fuel types, requiring the acquisition of hybrid models made up of the mixture of grass and shrub and the grass or shrub mixed with litter from forest canopy. Respecting meteorological conditions and shrub characteristics, field studies have shown significant differences between American and Mediterranean models. As a consequence, the definition of new Mediterranean models requires the adjustment of specific parameters such as fuel load by category (live and dead) and particle size class (1-, 10- and 100-h time-lag), fuelbed depth and surface area-to-volume ratio. These new parameters were obtained in situ of sample itineraries, prescribed fires, and forest fires. The availability of this new modeling, validated on a field of regional scale, will facilitate preventive planning and management as well as an efficient application of suppression techniques, both ground and aerial operations, required in defending a territory against forest fires.     

Quantifying economic losses from wildfires in black pine afforestations of northern Spain

We implemented a fire risk assessment framework that combines spatially-explicit burn probabilities, post-fire mortality models and public auction timber prices, to estimate expected economic losses from wildfires in 155 black pine stands covering about 450 ha in the Juslapeña Valley of central Navarra, northern Spain. A logit fire occurrence model was generated from observed historic fires to provide required fire ignition input data. Wildfire likelihood and intensity were estimated by modeling 50,000 fires with the minimum travel time algorithm (MTT) at 30 m resolution under 97^th percentile fire weather conditions. Post-fire tree mortality due to burning fire intensity at different successional stages ranged from 0.67% in the latest stages to 9.22% in the earliest. Stands showed a wide range of potential economic losses, and intermediate successional stage stands presented the highest values, with about 124 € ha^− 1 on average. A fire risk map of the target areas was provided for forest management and risk mitigation purposes at the individual stand level. The approach proposed in this work has a wide potential for decision support, policy making and risk mitigation in southern European commercial conifer forests where large wildfires are the main natural hazard.     

Fire-vegetation interplay in a mosaic structure of Quercus suber woodlands and Mediterranean maquis under recurrent fires

We examined the effects of fire recurrence on a mosaic structure of Quercus suber and Erica-Cistus shrubland communities of Southeastern France in order to improve the understanding of fire-vegetation interplay. Plant communities that were similar in 1959 (woodlands on shrublands called maquis on acidic soils) were compared along a gradient of fire recurrence, from 0 to 4 fires, with different time intervals between fires. The results showed that understory cover increased roughly with fire recurrence, whereas tree height, cover, density, stand basal area and litter depth decreased. Different fire recurrences along the past decades led to different vegetation types. High fire recurrence corresponded to maquis and sparse cork-oak woodlands while pure oak woodlands established in the absence of fire during the same period. In all, the diversity of tree diameter decreased with fire recurrence. High fire recurrence (3 or 4 fires in 50 years) led to a simple vertical structure of vegetation with a mono-layered shrub cover and few Quercus suber trees. In contrast, spatial connections between plants were maximal at longer time intervals, leading to a multi-layered vegetation. We finally discuss the potential implications of past fires on the behavior of future fires in the perspective of a sustainable management of these Mediterranean ecosystems.     

Land cover analysis in wildland-urban interfaces according to wildfire risk: A case study in the South of France

Each year, forest fires destroy about 500,000 ha of vegetation in Europe, predominantly in the Mediterranean region. Many large fires are linked to the land transformations that have taken place in the Mediterranean region in recent decades that have increased the risk of forest fires. On the one hand, agricultural fallows and orchards are slowly being colonized by vegetation, and on the other hand, the forest is not sufficiently used, both of which result in increased accumulation of fuel. In addition, urbanization combined with forest extension results in new spatial configurations called “wildland-urban interfaces” (WUI). WUI are commonly defined as “areas where urban areas meet and interact with rural lands, wildland vegetation and forests”. Spatial analyses were performed using a WUI typology based on two intertwined elements, the spatial organization of homes and the structure of fuel vegetation. The organization of the land cover in terms of representativeness, complexity or road density was evaluated for each type of WUI. Results showed that there were significant differences between the types of WUI in the study area. Three indicators (i) “fire ignition density”, derived from the distribution of fire ignition points, (ii) “wildfire density”, derived from the distribution of wildfire area and (iii) “burned area ratio”, derived from the proportion of the burned area to the total study area were then compared with each type of WUI. Assuming that the three indicators correspond to important aspects of fire risk, we showed that, at least in the south of France, WUI are at high risk of wildfire, and that of the different types of wildland-urban interfaces, isolated and scattered WUI were the most at risk. Their main land cover characteristics, i.e. low housing and road densities but a high density of country roads, and the availability of burnable vegetation such as forested stands and shrubland (garrigue) explain the high fire risk. Improving our knowledge of relationships between WUI environments and fire risk should increase the efficiency of wildfire prevention: to this end, suitable prevention actions and communication campaigns targeting the types of WUI at the highest risk are recommended.     

A comparison of the medieval and the current fire regimes in managed pine forests of Catalonia (NE Spain)

We compared the fire regimes in Mediterranean pine forests during two periods, 1370–1466 and 1966–1996 A.D. Medieval fire regime was estimated from the ‘claveria’ books of the Tortosa city, which record the city expenditures, including those for fighting fires that were burning in the city forest. We used the amount spent as an estimate of fire magnitude. Current fire regime was estimated for the same area from the local environment agency data bank, which includes date, location and burned area. The mean number of recorded fires per year, which mostly occurred in summer, is not significantly different between the two periods. Time-since-fire distributions of both periods fitted the negative exponential model, and they were not significantly different. The probability of fire occurring within 1-year interval was 0.44 for the 1379–1466 period and 0.46 for the 1966–1996 period. In both cases, small fires were more abundant, although there are some differences in the medieval series, 13% of all documented fires accounted for 47% of the suppression effort, whereas in the 20th century series, one single fire accounted for 88% of the area burned. Analysis of extreme fire also indicates that in the medieval series the largest fire per year needed one or less days of suppression effort in 58% of the years, whereas in the current period, fires were smaller than 1 ha in 78% of the years. We found that fire suppression in the Middle Ages was associated with forest exploitation. Although we cannot compare the two data sets accurately, there is not evidence of differences in fire frequency between the medieval and the current periods. Differences in fire magnitude distributions of both series of records may be explained by the different purposes and technical resources involved in the fire suppression practices.     

Determination of fire-access zones along road networks in fire-sensitive forests

Wild forest fires are one of the greatest environmental disasters affecting forest resources. Along the coastal zone of the Mediterranean region in Turkey,forested areas are classified as first-degree, fire-sensitive areas. Every year, thousands of hectares of forests have been destroyed in Turkey. In this study, fire-access zones were determined in the Mediterranean forests of Turkey, by utilizing geographic information systems(GIS) technology. The effective reach distance of fire hoses from both sides of roads was considered in order to delineate fireaccess zones. The effective reach distance can vary based on the technical capabilities and hydraulic capacity of fire trucks(minimum and maximum pressures on water pump);terrain structures(uphill, downhill and flat); and ground slope. These factors and their influences were studied in fire sensitive forest areas located in the eastern Mediterranean city of Kahramanmaras? in Turkey. First, terrain structures on both sides of the road network and groundslope classes were determined based on GIS data layers.Then, fire access zones were delineated according to water pressure data, terrain structures, and ground-slope classes.The results indicated that 69.30 % of the forested areas were within the fire-access zones, while the rest of the forest was out of reach the fire hoses. The accessible areas were also calculated for forested areas with different firesensitivity degrees. The accessible areas were 69.59, 69.96,and 67.16 % for the forested areas that are sensitive to fires at the first, second, and third degrees, respectively. This finding has implications for the monitoring and management of fire threats in areas outside of the reach distance.The outside areas should receive extra attention and monitoring during the fire season so that fires are detected ahead of time and management has sufficient time to react.Besides, new roads should be considered for these areas in order to access more lands in a shorter amount of time.     

世界森林雷击火研究现状和展望

野火是植物生态系统中最严重的自然灾害。野火的重要组成部分——雷击火是一种复杂且难以控制的自然现象，给人类和生态环境造成了巨大损失，人类活动已在全球范围内显著影响了雷击火的发生与分布。由于雷电的随机性，其观测实验和理论研究非常困难。因此雷击火成为全球变化及其环境影响研究的关键议题之一，各国对雷击火的预测研究给予了高度重视。结合相关研究文献发现，在雷击火形成因素、雷电预测预报模型、人工干预3个方面形成了较为系统的研究结果。文中在基于对其评述的基础上，总结雷击火的研究现状，展望未来的研究方向，以期为深入研究雷击火中能量来源——雷电和更高效地建立预测模型提供启发和参考。     

厄尔尼诺-南方涛动异常对森林火灾年际活动规律的影响

本文简要介绍了森林火灾年际活动中重灾时段(年)的客观规律性以及在所有被考察年价中的比重、损失状况,对运用ENSO预测预报森林火灾重灾年景的未来应用前景及可能产生的经济、生态效益作了评价,并论述了森林火灾(Forest Fire)与厄尔尼诺(El Nino)、南方涛动(Southern Oscillation)异常关系(缩写为FF-ENSO)研究的发展趋势及可能方向,以及避免或控制ENSO对森林火灾年际活动影响的对策。     

Forest fire risk zone mapping from satellite images and GIS for Baihe Forestry Bureau, Jilin, China

A forest fire can be a real ecological disaster regardless of whether it is caused by natural forces or human activities, it is possible to map forest fire risk zones to minimize the frequency of fires, avert damage, etc. A method integrating remote sensing and GIS was developed and applied to forest fire risk zone mapping for Baihe forestry bureau in this paper. Satellite images were interpreted and classified to generate vegetation type layer and land use layers （roads, settlements and farmlands）. Topographic layers （slope, aspect and altitude） were derived from DEM. The thematic and topographic information was analyzed by using ARC/INFO GIS software. Forest fire risk zones were delineated by assigning subjective weights to the classes of all the layers （vegetation type, slope, aspect, altitude and distance from r3ads, farmlands and settlements） according to their sensitivity to fire or their fire-inducing capability. Five categories of forest fire risk ranging from very high to very low were derived automatically. The mapping result of the study area was found to be in strong agreement with actual fire-affected sites.     

气候变化背景下森林火灾发生规律研究

随着气候变暖加剧,全球森林火灾灾害发生的频率与强度亦随之增加,世界各地森林火灾潜 在的危险将长期存在,严重程度也将大幅增加。森林火灾对森林生态资源和全球气候产生了重大影响, 由于其突发性强、破坏性大、处置救助极为困难,是当今世界最为严重的生态灾害和突发性公共事件之 一。森林火灾发生发展规律是森林火灾预防与扑救的重要依据,加强其规律研究有利于有的放矢地开展 森林防灭火工作。针对气候变化现状及发展态势,结合气候变化背景下国内外森林火灾现状,系统论述 了气候变化对我国森林火灾发生发展规律的影响,主要阐述了气象条件影响森林火灾的发生,气候影响 森林可燃物,气候影响森林火源,气象影响森林火行为,气候决定森林火灾周期以及气候变化对森林火 灾时空分布规律的影响。在全球气候变暖的背景下,从解析我国森林火灾发生规律入手,通过气候变化 背景下我国森林火灾发生规律的研究,客观认识我国和各地区森林火灾发生发展规律,从而为国家和地 方各级政府有效开展森林火灾灾害防治和应急管理工作、切实保障社会经济可持续发展提供科学决策 依据。     

2000年全球森林火灾评述

2000年受气候异常、高温、干旱的影响,世界范围内森林火灾频繁发生。美国、欧洲环地中海国家、俄罗斯、蒙古、南非、韩国、印度尼西亚等国家都发生了大的森林火灾,造成重大经济损失和环境破坏,严重威胁居民的生命和财产安全。其中美国西部、俄罗斯远东发生的森林火灾最为严重,引起世界各国的广泛关注。     

Forest Fires and Prevention Strategies in Northwestern Region of China

The paper described the natural conditions and forest types in Northwestern Region of China. Most forests in the region are distributed in subalpine areas. It is important to protect the existent forests in the region for maintaining ecological balance. According to the statistics results of 1991~2000, the paper analyzes the forest fires distribution and fire severity. Annually the numbers of forest fires range from 52 to 240. The incidence rate of forest fires in Northwestern Region is under 0.33 per ten thousand ha. There are 0.67-64.4 ha burned area per ten thousand ha forest. The main reasons for forest fires lie in the dry weather conditions, many firebrands, and high fuel loading. The strategies of fire management in the region are to stress the fire education in forest regions, strength the firebrands' management, emphasize the fuel management, and improve the fire monitoring and fire control ability.     

A computer-system that classifies the prefectures of Greece in forest fire risk zones using fuzzy sets

All of the Mediterranean countries face a serious forest fire problem. The main factors that affect the problem of forest fires in Greece are vegetation, climate conditions and most of all, arson (Proceedings of Forest Fires in Greece, Thessaloniki, 1990, p. 97). In Greece, after 1974, the number of forest fires and the total burned areas have risen dramatically. The design of an effective fight and prevention policy is a very important matter, as it can minimize the destruction. This paper describes an expert system that classifies the prefectures of Greece into forest fire risk zones, using a completely new methodology. The concept of fuzzy expected intervals (F.E.I.) was defined by Kandel and Byatt (Proc. IEEE, 66, 1978, 1619) and offered a very good approach towards forest fire risk classification. Fuzzy expected intervals are narrow intervals of values that best describe the forest fire problem in the country or a part of the country for a certain time period. Fuzzy logic was applied to produce a F.E.I. for each prefecture of the country. A successful classification of the prefectures of Greece (in forest fire risk zones) was performed by the expert system by comparing the produced fuzzy expected intervals to each other and by using a supervised machine learning algorithm that assigns a certain weight of forest fire risk to each prefecture (Machine Learning, John Wiley and Sons, 1995).     

黑龙江省林火规律研究Ⅱ.林火动态与格局影响因素的分析

本文对在大尺度 (5 0 0km2 以上 )上影响黑龙江省林火的因素及其影响途径进行了分析。结果表明 ,年林火次数 (人为火次数 )与林业人口正相关 ,林火面积与人口无关。干燥度的空间差异对林火燃烧率格局有正向影响。林火特征与气候因子之间没有线性关系。黑龙江省林火次数和面积对年均温和降水量的响应可归纳为旋转的单叶双曲面和双叶抛物面两种模式。林火特征的周期与年均温、年降水量的周期关系很大。黑龙江省森林类型对林火次数、面积的影响在省级区划尺度上不显著的。较高的管理水平显著减少林火。林火次数、面积与了望塔数量、消防车数量及通讯覆盖率等无线性关系     

The European Forest Fire Information System in the context of environmental policies of the European Union

Since the mid-20th century, countries in Europe have been organized to record information on forest fires and their effects. These initiatives were established at regional and often national level, without major interaction among countries in Europe. With the expansion of the European Union in the 1980s, when Mediterranean countries were incorporated in the EU, the issue of forest fires increased in relevance, mainly due to the damages caused by fires in the natural areas of these countries. Initial EU policies related to fires date back to the 1980s, in which the European Union elaborated the first voluntary Regulations to support the development of forest fire information systems in the countries. Although EU environmental policies promoted the development of national systems, the first steps towards the development of a European fire information system did not take place until the late 1990s. Such a system was initially discussed between the European Commission services and the Member States in 1998. Although the development of the European Forest Fire Information System (EFFIS) started at this time, its official establishment came only in place with the publication of the Forest Focus regulation in 2003, which included within its implementation rules the reference to EFFIS. Since its establishment, EFFIS has influenced the further development of EU environmental policies on forest protection. It has further shaped the link of these to other forest and regional policies, which, although not fire-specific, did address the issue of damages caused by fires to the European environment and its population. The present article describes the steps in the development of the EU fire policies and EFFIS. It provides a synoptic view of how fires are included in different sectoral policies of the EU, and suggests ways in which the continuation of forest fire monitoring and management may be included in future European policies.