Characterization of forest fires in Catalonia (north-east Spain)

The present study analyses the temporal variation in the distribution of the number of fires, area burned and fire sizes in Catalonia using fire data from 1942 to 2002. The study shows variations in the distribution of fire size over recent decades, with a significant increase in the number of very large fires. The study also analyses relationships between characteristics of the forest (altitude, slope, aspect, living fuels and species composition) and the probability of the fire occurrence. The analysis is based on the overlay of forest cover data and perimeters of forest fires during the period (1986–2002). Of the analysed variables, altitude affects most the probability of fire occurrence, with higher proportions of burned forest area at lower altitudes. Stand’s vertical structure is also relevant, with lower proportions of burned area in stands with mature tree cover without understory. The study helps to analyse the strengths and weaknesses of forest and fire management policies, especially those related to forest and fuel management at the landscape level.     

METHODS OF EVALUATING FOREST FIRE HISTORY

Forest fire history can be reconstructed over past centuries across a widevariety of forest types.Fire scars on living tress,and age classes of forest stands,are thetwo sources of information for these reconstructions.Point and area frequencies are usedto reconstruct fire history.Point frequencies are useful in forest types that burn withfrequent,low intensity fire so that many fire-scarred residual trees exist.A true point isa single tree,but more often point estimates are made by combining fire scar records fromseveral adjacent trees.Area frequences are applied where fires are infrequent but ofmoderate to high intensity,so that stand ages are used across wide areas to estimate firereturn interals.Proper selection and application of fire history methods are essential toderiving useful ecological implications from fire history studies.This review evaluates the common methods of determining fire history:what thetechniques are,where they are best applied,and how to interpret them in an ecologicalcontext.E     

Post-fire analysis of pre-fire mapping of fire-risk: A recent case study from Mt. Carmel (Israel)

The recent devastating wildfire on Mt. Carmel provided a unique opportunity to evaluate a fire-risk map constructed for the region, published two years ago in this journal. This largest forest fire in the history of Israel, occurred during December 2010, covering 2180 ha, burning more than half-million trees and causing the loss of life of 45 people.A study of fire risk in this area was conducted between 2007 and 2009 utilizing a combination of Monte Carlo simulation of spatial spread of fire ignition with fire behavior model (FARSITE). The fire risk map produced in 2009 is assessed here with reference to the area burnt during December 2010. The results showed that most of burnt areas corresponded to high risk levels in the risk map. According to a null model, the five lower risk levels taken together would have corresponded to 50% of the burnt area, while in fact they were presented in only 5.6% of the area. In contrast, the three highest risk levels, for which the null model expectation would be a representation of 30%, were represented in 87% of the area. Comparing the fire risk map against the map of the real recent fire provided support to the general approach, and strengthened the confidence of our fire risk model.     

Study on Forest Fire Occurrence in China

China is not rich in natural forest sources. Owing to natural and historical factors, forest fires have long been frequenting China. Forest fire prevention is the most important of all. Forest fire prevention and controlling have long been held as a very important factor in our ecological plans. Taking china 's special geographical location, topography, climate and the distribution of forest sources into consideration, we have every reason to believe that forest fires in China have their own special environment and occurrence. China suffers forest fire hazards heavily. Forest fires arise occasionally from thunderstruck or self-burning of peat. However, most fires are due to man's fault while inappropriately using fires in production and daily life. Since China is located in the Northern Hemisphere with a vast territory, there is a striking difference in the climate between South China and North China.     

Assessing fire risk using Monte Carlo simulations of fire spread

Understanding the spatial pattern of fire is essential for Mediterranean vegetation management. Fire-risk maps are typically constructed at coarse resolutions using vegetation maps with limited capacity for prescribing prevention activities. This paper describes and evaluates a novel approach for fire risk assessment that may produce a decision support system for actual fire management at fine scales. FARSITE, a two-dimensional fire growth and behavior model was activated, using ArcView VBA code, to generate Monte Carlo simulations of fire spread. The study area was 300 km² of Mt. Carmel, Israel. FARSITE fuel models were adjusted for Mediterranean conditions. The simulation session consisted of 500 runs. For each simulation run, a calendar date, fire length, ignition location, climatic data and other parameters were selected randomly from known distributions of these parameters. Distance from road served as a proxy for the probability of ignition. The resulting 500 maps of fire distribution (the entire area burnt in a specific fire) were overlaid to produce a map of ‘hotspots’ and ‘cold spots’ of fire frequency. The results revealed a clear pattern of fires, with high frequency areas concentrated in the northwestern part. The spatial pattern of the fire frequency map bears partial resemblance to the fuel map, but seems to be affected by several other factors as well, including the location of urban areas, microclimate, topography and the distribution of ignition locations (which is affected by road pattern). These results demonstrate the complexities of fire behavior, showing a very clear pattern of risk level even at fine scales, where neighboring areas have different risk levels due to combinations of vegetation cover, topography, microclimate and other factors.     

关于森林燃烧火行为特征参数的计算与表述

森林的燃烧过程极为复杂 ,火行为是森林可燃物燃烧的一系列现象的总和。国内外林火研究人员多年来致力于火行为特征的研究描述 ,在火场范围 (周长或面积 )、火焰特征、火强度、火头的蔓延速度等方面取得了一些显著的进展 ,其中火强度、火焰高度和火蔓延速度是林火行为的 3大指标。火行为直接受火环境的影响。     

The role of fire in forest dynamics in Daxinganling region

Recent fire statistics and preliminary fire history data suggest that fire has been historically responsible for maintaining the vegetative communities up to present in Daxinganling region. Forest types, and even tree species, arc dependent on the degree of fire intensity, fire size, depth of burn and fire frequency. Selected samples of larch, pine, birch and spruce forest were studied in terms of species composition as determined by fire frequency which mainly depends on topography and site conditions. Intervals between fires range between 6 and 170 years.     

Historic and current fire regimes in the Great Xing’an Mountains,northeastern China: Implications for long-term forest management

Understanding both historic and current fire regimes is indispensable to sustainable forest landscape management. In this paper, we use a spatially explicit landscape simulation model, LANDIS, to simulate historic and current fire regimes in the Great Xing’an Mountains, in northeastern China. We analyzed fire frequency, fire size, fire intensity, and spatial pattern of burnt patches. Our simulated results show that fire frequency under the current fire scenario is lower than under the historic fire scenario; total area burnt is larger with lower fire intensity under the historic fire scenario, and smaller with higher fire intensity under the current fire scenario. We also found most areas were burned by high intensity fires under the current fire scenario, but by low to moderate fires under the historic fire scenario. Burnt patches exhibit a different pattern between the two simulation scenarios. Large patches burnt by high intensity class fires dominate the landscape under the current fire scenario, and under historic fire scenario, patches burnt by low to moderate fire intensity fires have relatively larger size than those burnt by high intensity fires. Based on these simulated results, we suggest that prescribed burning or coarse woody debris reduction should be incorporated into forest management plans in this region, especially on north-facing slopes. Tree planting may be a better management option on these severely burned areas whereas prescribed burning after small area selective cutting, retaining dispersed seed trees, may be a sound forest management alternative in areas except for the severely burned patches.     

Forest Fire History in Viena Karelia,Russia

The history of forest fires was studied in north-west Russia near the Finnish-Russian border on a total of 22 transects within a 3 x 4 km area, 100 m long and 20 m wide, bydendrochronological methods. In total, 25 fires were identified as having occurred in the area between 1400 and 1998. On average, a fire occurred somewhere within the area once every 23 yrs, and once every 13 yrs between 1650 and 1950. The fire frequency (proportion of the area burnt per time unit) broadly followed the changes in the number of fires, but there were also differences. The fire frequency was 1.87% from 1679 to 1872 and 0.40% from 1873 onwards. The mean fire interval was 62 yrs and the median interval 56 yrs. According to the tree-ring width chronology tree growth was significantly lower in the dated fire years than in other years. Forest fire history in north-west Russia is broadly similar to that in many parts of Scandinavia.     

城市森林火灾隐患及其管理

人为纵火、林区吸烟、施工用火、闪电、林区建筑物以及不合理的城市森林规划等是城市森林火灾发生的重要隐患,常常导致城市森林火灾的发生,给城市居民的生命和财产造成了巨大的损失。加强对城市森林火灾发生原因的研究,合理规划城市森林布局和结构,加强对火灾隐患的管理,减少城市森林火灾的发生,是维护城市生态可持续发展的必然要求。       

Fire cycle and fire adaptation of main tree species in Daxing’anling forest region,China

Based on the fire statistics, the Daxing’anling forest area were classified into three fire cycle regions: northern coniferous virgin forest region with a fire cycle ofl 10–120 years, middle conifer-broad-leaved mixed forest region with a fire cycle of 30–40 years, and southern broad-leaved secondary forest region with a fire cycle of 15–20. The percentage of conifers and broad-leaved trees, forest age and natural mature period of main tree species in different fire cycle regions were discussed in concern with fire occurrence. The characteristics of fire adaptation and fire resistance of main tree species, such as sexual and asexual reproduction, were discussed and evaluation of the synthetical fire adaptation was made.     

Using Monte Carlo simulations to estimate relative fire ignition danger in a low-to-medium fire-prone region

A comprehensive assessment of fire ignition danger is nowadays a basic step towards the prioritization of fire management measures. In this study we propose performing a fire selectivity analysis using Monte Carlo simulations to statistically estimate the relative fire ignition danger in a low-to-intermediate fire-prone region such as Canton Ticino, Switzerland. We define fire ignition danger as the likelihood that at a given place a fire will be ignited. For each 25 m × 25 m pixel of the study area, landscape characteristics that may be related to the probability of fire ignition such as vegetation type, elevation, aspect, slope, urban-forest interface were first split into 9-12 categories. The selectivity of each category with respect to fire ignition was then statistically tested by means of Monte Carlo simulations. Finally, we proposed two different approaches for calculating the ignition danger index: cumulating the scores of the Monte Carlo simulations to a final index or producing synthetic scores by performing a principal component analysis of the Monte Carlo results. The validation of the resulting fire danger indices highlights the suitability of both proposed approaches. The PCA-option allows a slightly better discrimination between ignition and non-ignition points and may be of more general application.     

Prehistoric fire area and emissions from California's forests,woodlands, shrublands,and grasslands

In the majority of US political settings wildland fire is still discussed as a negative force. Lacking from current wildfire discussions are estimates of the spatial extent of fire and their resultant emissions before the influences of Euro-American settlement and this is the focus of this work. We summarize the literature on fire history (fire rotation and fire return intervals) and past Native American burning practices to estimate past fire occurrence by vegetation type. Once past fire intervals were established they were divided into the area of each corresponding vegetation type to arrive at estimates of area burned annually. Finally, the First Order Fire Effects Model was used to estimate emissions. Approximately 1.8 million ha burned annually in California prehistorically (pre 1800). Our estimate of prehistoric annual area burned in California is 88% of the total annual wildfire area in the entire US during a decade (1994–2004) characterized as “extreme” regarding wildfires. The idea that US wildfire area of approximately two million ha annually is extreme is certainly a 20th or 21st century perspective. Skies were likely smoky much of the summer and fall in California during the prehistoric period. Increasing the spatial extent of fire in California is an important management objective. The best methods to significantly increase the area burned is to increase the use of wildland fire use (WFU) and appropriate management response (AMR) suppression fire in remote areas. Political support for increased use of WFU and AMR needs to occur at local, state, and federal levels because increasing the spatial scale of fire will increase smoke and inevitability, a few WFU or AMR fires will escape their predefined boundaries.     

森林泡沫灭火枪的研制

森林泡沫灭火枪是以轻型泵为动力,将森林泡沫剂与水混合后迅速变成泡沫。直接用于灭火的喷泡工具,主要由接口、接头、喷嘴、枪体等部分组成。野外灭火试验表明,该枪灭火效果较好。     

Fire history of coniferous riparian forests in the Sierra Nevada

Fire is an important ecological process in many western U.S. coniferous forests, yet high fuel loads, rural home construction and other factors have encouraged the suppression of most wildfires. Using mechanical thinning and prescribed burning, land managers often try to reduce fuels in strategic areas with the highest fuel loads. Riparian forests, however, are often designated as areas where only limited management action can take place within a fixed-width zone. These highly productive forests have developed heavy fuel loads capable of supporting stand-replacing crown fires that can alter wildlife habitat and ecosystem function, and contribute to stream channel erosion. Objectives of this study were to determine whether adjacent coniferous riparian and upland forests burned historically with different frequencies and seasonalities, and whether these relationships varied by forest, site, and stream characteristics. We measured dendrochronological fire records in adjacent riparian and upland areas across a variety of forest, site and stream conditions at 36 sites in three sampling areas in the northern Sierra Nevada.     

FIRE CYCLE AND FIRE ADAPTATION OF MAIN TREE SPECIES IN DAXING''''ANLING FOREST REGION, CHINA

FIREENVIRONMENT,FUELSANDFlRECAUSESFireEnvir0nmcntDaxing'anlingf0restareabelongstothefrigid-temPeratemonsoonclimate.Ithasalongwinterandashortsununer.Thereare9monthsofdailytemPeratUreunderlOCandlessthan3OdaysofdailytemPerabeabove22C.ThemeantemperatUreinthecoldestmonth(January)is-25V~-30C,withtheextrCmeof-52.3C,andinthewarmestmonth(July)isl5~2OC,withtheextremeof39C.Thegrowingsea-soninthisareaisonly9O~ll0days.Theaverageannualprecipitationisabout35O~500nun,and80Percentofwhich…     

FIRE IN NORTHEAST CHINA FORESTS

Fire plays an important role in Northeast China forests,The occurrence of fires isclosely related to the environmental characteristics.High temperature,drought,and strong wind inspring(March to July)and autumn(September to November)are common fire climatic character-istics in Northeast China.Based on the chemical and physical characters of fuels,fuel quantity dis-tribution,sites as well as fire potential behaviour,fourteen fuel types have been classified inNortheast China Forest area.The fire adaptation of several main tree species has been also analysedin this paper.These species are widely distributed and of great economic significance in NortheastChina.Fire use is paid much more attention recently.Fire have been employed in many silviculturepractice such as fireline creation,fuels reduction and seed bed preparation in Northeast China     

除草剂法维护改培型生物防火林带对森林植被环境的影响

采用化学除草剂方法维护改培型生物防火林带对林带内乔木树种结构没有影响,对草本和灌木的丰富度、盖度结构有一定影响;除草剂维护改培型生物防火林带对周围近距离(15 m)处草本、灌木物种的丰富度、盖度结构有一定影响,对距离30 m以上植被结构没有影响,仍属均匀、稳定群落结构。     

LFP—86型木材阻燃剂性能的研究

LFP—86型木材阻燃剂是一种含有氮、磷的微黄色透明液体。试验证明,LFP-86型阻燃剂处理的水曲柳材的氧指数为57,达到JIS D1201—77难燃一级水平。当木材的阻燃剂吸收量达60kg/m~3以上,在1000℃燃烧3分钟后的失重率为20%左右。LFP—86型阻燃剂不抗菌、不防蚁。阻燃材的冲击韧性、胶合强度、抗吸湿性稍有降低,对油漆、金属腐蚀无影响。LFP—86型阻燃剂适用于室内木材的阻燃处理。     

STUDY ON KOREAN PINE FUEL TYPES

Koreanpine(Pnuskorabois)isoneofthemostimpohanttrdesPeCiesinnortheastChina,anddistributesnatUraIlyintheeastmountains(theXiaoxing'anMountainsandtheChangbaiMountains)ofthearea.Alongwiththedevelopmentofforestindusnyinthisarea,thevirgnforestSredueeraPidly,andtheplan-tationsofthesPeCiesincreaseyearly.KoreanpineplantationsaremuchmorecombustiblethanitSnaturalforestS(broad-leaVdsoreanpineforestS).FueltyPesIUdyinChinabeganinearlyl98o's.ThereisnosystematicstUdyonKoreanpinefueltyPesuptonow.Base…