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     

Satellite remote-sensing technologies used in forest fire management

Satellite remote sensing has become a primary data source for fire danger rating prediction, fuel and fire mapping, fire monitoring, and fire ecology research. This paper summarizes the research achievements in these research fields, and discusses the future trend in the use of satellite remote-sensing techniques in wildfire management. Fuel-type maps from remote-sensing data can now be produced at spatial and temporal scales quite adequate for operational fire management applications. US National Oceanic and Atmospheric Administration (NOAA) and Moderate Resolution Imaging Spectroradiometer (MODIS) satellites are being used for fire detection worldwide due to their high temporal resolution and ability to detect fires in remote regions. Results can be quickly presented on many Websites providing a valuable service readily available to fire agency. As cost-effective tools, satellite remote-sensing techniques play an important role in fire mapping. Improved remote-sensing techniques have the potential to date older fire scars and provide estimates of burn severity. Satellite remote sensing is well suited to assessing the extent of biomass burning, a prerequisite for estimating emissions at regional and global scaleswhich are needed for better understanding the effects of fire on climate change. The types of satellites used in fire research are also discussed in the paper. Suggestions on what remote-sensing efforts should be completed in China to modernize fire management technology in this country are given.     

Fire behavior characteristics in a pine needle fuel bed in northwest Africa

This paper reports results of research to validate a fire behavior model "Wildland Fire Dynamics Simulator" through comparison of laboratory-scale measurements under the oxygen consumption calorimetry principle to several simulation runs of ground fire spreading in a fuel bed under wind. Pine needle ground covers of Pinus halepensis Mill. and Pinus pinaster Ait., two pine species in a specific region in northwest Africa were tested. In order to gain a deeper understanding of forest fire behavior, investigation into the rate of spread, one of the most relevant quantities used in forest fire science, is fundamental. Moreover, the heat release rate of the fire spread for different fuel types and related thermal functions such as radiant, convective and conductive heat transfer through beds of pine needles were quantified. The results can be helpful for the improvement and validation of the computational Fluid Dynamics CFD model and give global information on fire spread under wind on a bed of pine needles.     

Modeling surface fuels moisture content in Pinus brutia stands

Fuel moisture content is an important variable for forest fires because it affects fuel ignition and fire behavior. In order to accurately predict fuel ignition potential, fuel moisture content must be assessed by evaluating fire spread, fireline intensity and fuel consumption.Our objective here is to model moisture content of surface fuels in normally stocked Calabrian pine(Pinus brutia Ten.) stands in relation to weather conditions, namely temperature, relative humidity, and wind speed in the Mugla province of Turkey. All surface fuels were categorized according to diameter classes and fuel types. Six fuel categories were defined: these were 0–0.3, 0.3–0.6, and0.6–1 cm diameter classes, and cone, surface litter, and duff. Plastic containers 15 9 20 cm in size with 1 9 1 mm mesh size were used. Samples were taken from 09:00 to19:00 h and weighed every 2 h with 0.01 g precision for10 days in August. At the end of the study, samples were taken to the laboratory, oven-dried at 105 °C for 24 h and weighed to obtain fuel-moisture contents. Weather measurements were taken from a fully automated weather station set up at the study site prior to the study. Correlation and regression analyses were carried out and models were developed to predict fuel moisture contents for desorption and adsorption phase for each fuel type categories. Practical fuel moisture prediction models were developed for dry period. Models were developed that performed well with reasonable accuracy, explaining up to 92 and 95.6%of the variability in fuel-moisture contents for desorption and adsorption phases, respectively. Validation of the models were conducted using an independent data set and known fuel moisture prediction models. The predictive power of the models was satisfactory with mean absolute error values being 1.48 and 1.02 for desorption and adsorption as compared to the 2.05 and 1.60 values for the Van Wagner's hourly litter moisture content prediction model. Results obtained in this study will be invaluable for fire management planning and modeling.     

STUDY ON THE NETWORK OF FOREST BURNING LINKS

Based on the research of the Forest Burning Links published in the Journal ofNortheast Forestry University in 1987,this paper continues to study the theory of forest burningFire behavior has been divided into two important series in this paper.One is fire occurrence andspread, and the other is burning intensity.The first series has been divided into three grades as A:toburn difficulty and spread slowly;B:to burn possibly and spread little fast;and C:to burn easilyand spread fast.The second series has been divided into four grades as I:light burning;Ⅱ:me-dium burning;Ⅲ:intense burning;and Ⅳ:severe burning.The firsts series can be put as ordinate,and the second series can be put as abscissa.Then the network of 12 forest burning links can beformed.In the network,the relatioship,the law of distribution and the variation of different forestburning links can be shown clearly.The studies of the distrubution of fuel types,topography,siteand fire kinds in the network can provide the basic theory for fire mana     

Application of Poisson Regression Model and Negative Binomial Regression Model in Forest Fire Forecasting

A Poisson regression model and a negative binomial regression model(NB model) are often used in areas such as medicine and economy,but rarely in the domestic forestry sector,especially in the forest fire forecasting.Based on the data of forest fire occurrences in Daxing’anling region in 1980- 2005,this paper profoundly analyzes the application conditions and test methods of the two models.The AIC method was used to check the fitting level of the models and the capability of the models for forecasting forest fires was discussed.This study provided necessary theoretical basis and data support for the application of the two models in the field of forestry in China.     

CLASSIFICATION OF FIRE DANGER RATING AREA IN CHINA

INTRODUCTIONAfter the heavy fire happened inDaxinganling Mountains in1987,fire asone of the important part in forestry is paidmuch attention all over China in recentyears.Becauce of the lack of national fund,45 million Yuan can not meet the needs ofbasic construction and fire equipments re-newing,therefore,it is necessary to classifyfire danger rating area all over the countryto put this limited fund in key.Many coun-tries over the world paid much attention tothis classification of fire danger rating areaand provided many different researchmethods.     

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.     

Study and Application of Fuel-breaks in Southwest China

All of the plants can be combusted. The mechanism of forest belts resistance is that the tree species weren‘t liable to be burned compared with other plant species. In this paper new concepts on fire resistant trees and fuel-breaks trees were presented. The fire resistance mechanism includes 3 aspects, fire-resistant tree species, rational construction forest belts and environment. Tree crowns can resist fire forwarding. Forest belts can form the environment, which is not easy to fire, and also make fuels distributed discontinuous. The network of forest belts has large area of conifer forest segregated. The ideal f‘ire resistant tree species had better to embrace some characteristics, such as high f‘ire resistance, rational planting and biological characteristics.     

森林火险等级预报系统评述

对当前世界上主要的森林火险等级系统进行了综述, 包括加拿大、美国、澳大利亚以及其他一些国家的森林火险等级系统。对主要森林火险等级系统的组成、结构和发展过程进行了比较, 讨论了这些系统应用的局限性。比较了世界上3个应用比较普遍的森林火险等级系统的发展、可燃物类型、输入因子、输出因子和应用范围, 认为发展中国的森林火险等级系统采用加拿大的森林火险等级系统(CFFDRS)的技术比较合适。我们可直接应用CFFDRS, 然后根据当地气候和可燃物类型对火险等级系统进行校正。     

韩国国家森林火险等级预报系统概述

在全球气候变化背景下, 借鉴美国和加拿大先进的森林火险等级预报系统的经验, 尤其是借鉴其他国家消化吸收美、加两国森林火险等级预报系统的成功做法是提高我国森林火灾综合防控能力的有效途径。文中介绍了韩国国家森林火险等级预报系统(KFFDRI)研建过程及其原理与方法等技术细节, 比较了KFFDRI与美国国家火险等级系统(NFDRS)及加拿大森林火险等级预报系统(CFFDRS)的不同, 以期对我国构建国家森林火险等级预报系统提供技术参考。     

乐山市森林火险等级区划的研究

在广泛收集、整理乐山市各县区森林资源、植被类型、农业人口分布、气象诸因子及林火资料的基础上,按照林业部制定的《全国森林火险区划》标准,进行森林火险等级区划。全市森林火险等级区划１４个单位（１３个区、市、县、１个林业企业局）,区划为Ｉ级火险区３个,Ⅱ级火险区３个,Ⅲ级火险区８个。同时应用聚类分析、多元回归分析,分析火险因子与历年发生火灾所造成损失的回归关系。     

樟子松针叶床层结构对失水过程中含水率参数的影响

以樟子松针叶床层为例,初步研究可燃物结构床层结构特征对其失水过程中时滞和平衡含水率参数(基于Nelson模型)的影响。通过对15个不同厚度、载量、密度的樟子松可燃物床层的失水过程的分析,估计这些床层的时滞和平衡含水率参数,利用这些参数进行可燃物含水率模拟的平均绝对误差和均方根误差均不超过0.01,所估计的可燃物含水率参数有效。对可燃物床层结构特征对这些参数的影响的研究表明,可燃物床层厚度和载量对时滞和平衡含水率的2个参数a、b具有有显著影响,与时滞和平衡含水率参数b正相关,与平衡含水率参数a负相关,据此建立可燃物含水率参数的预测模型。该模型高估了时滞和平衡含水率参数b,低估了平衡含水率参数a。所得结果还有一些不确定性,特别是可燃物结构特征对平衡含水率参数的影响,需要在更宽的温湿度范围内、针对其他平衡含水率模型和在失水吸水2个过程上进一步研究。     

卫星遥感技术在林火管理与研究中的应用(英文)

卫星遥感已经成为森林火险等级预测、可燃物和火烧区制图、林火监测和火生态研究的一个主要数据来源。本文综述了这些研究领域的研究成果,分析了未来林火管理中采用的卫星遥感技术的发展趋势。根据卫星遥感数据制取的可燃物分布图可以满足林火管理在空间和时间尺度上的需要。单独采用遥感数据或结合地面气象数据可以生成一些火险指数,用于森林火险的预报。目前NOAA 和MODIS 卫星由于有高的时间分辨率已被广泛用于林火探测和监测,这些监测结果可以在许多林火网站上见到,这为世界各地的林火管理和研究提供了重要的参考资料。作为低成本的有效工具, 卫星遥感技术在确定火烧面积和过火区制图上发挥了重要作用。遥感技术的发展也可以用来推断火烧时间和估计火烧程度。卫星遥感也非常适合用来估计生物燃烧面积,这是估计全球或区域生物燃烧排放量和理解火对全球变化的影响的基础。本文还讨论了林火研究中采用的卫星类型。文章最后建议中国需要在卫星遥感技术的应用上进一步发展,提高我国的林火管理水平。参71。     

Modeling topographic influences on fuel moisture and fire danger in complex terrain to improve wildland fire management decision support

Fire danger rating systems commonly ignore fine scale, topographically-induced weather variations. These variations will likely create heterogeneous, landscape-scale fire danger conditions that have never been examined in detail. We modeled the evolution of fuel moistures and the Energy Release Component (ERC) from the US National Fire Danger Rating System across the 2009 fire season using very high resolution (30 m) surface air temperature, humidity and snow ablation date models developed from a network of inexpensive weather sensors. Snow ablation date occurred as much as 28 days later on North-facing slopes than on South-facing slopes at upper elevations. South-facing slopes were hotter and drier than North-facing slopes but slope position, in addition to aspect, was also important because nocturnal air temperatures were coolest and humidity was highest in valley bottoms. These factors created heterogeneous fuel moistures and fire danger across the study area. In the late season (August and September), nocturnal cold air drainage and high relative humidity fostered fuel moisture recovery in valley bottoms, where fuel moistures and ERC values were 30% and 45% higher and lower, respectively at peak fire danger (September 29th). Dry fuel moistures and relatively high ERC values persisted on low elevation, South-facing slopes. The driest conditions were observed 100-200 m above the valley floor where mid-slope thermal belts frequently developed above areas of cold air pooling. We suggest that a complete understanding of these variations may help improve fire management decision making.     

永安市森林火险等级区划研究

针对永安市森林火灾发生特点与规律 ,参照YL10 6 3 - 92《全国森林火险区划等级》 ,按照农业人口密度、路网密度、气温、风速、降水量、树种 (组 )燃烧类型的指标值与立木蓄积量和有林地、未成林面积等火险因子 ,求算两项综合得分值 ,确定火险等级。     

Effects of fuel treatments on fire severity in an area of wildland–urban interface,Angora Fire,Lake Tahoe Basin,California

The Angora Fire burned 1243 ha of Jeffrey pine and mixed conifer forest in the Lake Tahoe Basin between June 24 and July 2, 2007. The Angora Fire burned at unusually high severity due to heavy fuels; strong winds; warm, dry weather; and unseasonably low fuel moistures. The fire destroyed 254 homes, and final loss and suppression cost estimates of $160,000,000 make the Angora Fire one of the ten costliest wildfires in US history. The Angora Fire burned into 194 ha of fuel treatments intended to modify fire behavior and protect private and public assets in the Angora Creek watershed. The fire thus provides a unique opportunity to quantitatively assess the effects of fuel treatments on wildfire severity in an area of wildland–urban interface. We measured fire effects on vegetation in treated and adjacent untreated areas within the Angora Fire perimeter, immediately after and one year after the fire. Our measures of fire severity included tree mortality; height of bole char, crown scorch, and crown torch; and percent crown scorch and torch. Unlike most studies of fuel treatment effectiveness, our study design included replication and implicitly controlled for variation in topography and weather. Our results show that fuel treatments generally performed as designed and substantially changed fire behavior and subsequent fire effects to forest vegetation. Exceptions include two treatment units where slope steepness led to lower levels of fuels removal due to local standards for erosion prevention. Hand-piled fuels in one of these two units had also not yet been burned. Excepting these units, bole char height and fire effects to the forest canopy (measured by crown scorching and torching) were significantly lower, and tree survival significantly higher, within sampled treatments than outside them. In most cases, crown fire behavior changed to surface fire within 50 m of encountering a fuel treatment. The Angora Fire underlines the important role that properly implemented fuel treatments can play in protecting assets, reducing fire severity and increasing forest resilience.     

森林火险中长期预测预报研究进展

概述了我国和美国、加拿大的森林火险中长期预测预报的理论和方法。国内研究大多建立在对历史火灾资料与气象资料进行统计分析研究的基础上, 预测结果多是定性的、间断性的。美国和加拿大则依托成熟的全国性森林火险等级系统, 结合气象局的中长期降水和温度预报, 给出各火险指数实时的一周尺度预报及每周1次的16周尺度的季节性预报。我国今后应加强森林火险的中长期预测预报研究, 要由单纯定性分析转向定量化研究, 由一般数理统计模型转向具有明显物理意义的数学物理模型。