A comparison of forest fire indices for predicting fire risk in contrasting climates in China

The relationships between fire danger indices and fire risk have been extensively studied in many regions of the world. This work uses partial effect analysis in semiparametric logistic regression models to assess the nonlinear relationships among location, day, altitude, fire danger indices, normalized difference vegetation index (NDVI), and fire ignition from 1996 to 2008 in four different climatic regions in China. The four regions are North China (NR), Northeast China (NE), Southeast China (SE), and Southwest China (SW). The three main results are as follows: First, different fire danger indices are selected as significant variables dependent on the region. The inter-regional difference could be partially explained by difference in local weather and vegetation conditions. Second, spatial location exerts highly significant effects in all four regions. NDVI values are selected as explained variable for NR, NE, and SE on fire ignitions. On a daily scale, altitude influences fire ignition for NR, SE, and SW. Third, the robustness of the probability models used in NE, SE, and SW is better than that in NR on a daily scale. The semiparametric logistic regression model used in this study is useful for assessing the ability of fire danger indices to estimate probabilities of fire ignition on a daily scale. This study encourages further research on assessing the predictive ability of fire danger indices developed at other temporal and spatial scales in China.     

Factors affecting grassland succession retardation in the Juifang area

This study classifies the vegetation status to determine the factors affecting grassland succession retardation in the Juifang area. Data derived from Land Use Investigation of Taiwan, GIS techniques, multivariate analysis, and on-site investigation was applied in this research. Discriminant analysis shows that forests that have low human disturbance cannot be correctly identified and classified by the topography and soil depth. This indicates that the topography and soil depth in the Juifang area are not the limiting factors of forest growth. Grasslands are usually susceptible to periodic wildfires. This can be used as an environmental index for disturbed and/or polluted soils. Comparing the current vegetation status with the vegetation distribution derived from discriminant analysis, potential wildfire frequency can be estimated. Acid sulfate soils and copper-contaminated soils are the major polluted soils in the Juifang area. Because the Juifang area is an important coal field in northern Taiwan, acid sulfate can be easily found in the spoiled soils of several mining spots due to sulfur oxidation from the soil and/or rock layers dug out during mining operations. Copper-contaminated soils were detected at the sites near the Li-Lo Copper Refining Plant and Taiwan Metal Mining Company. Polluted soils and periodic wildfires inhibiting the invasion of trees are the major factors retarding the succession of grasslands in the Juifang area.     

GIS-based multi-dimensional risk assessment of the grassland fire in northern China

This study presents a methodology for risk analysis and assessment to manage grassland fire in northern China based on the Geographical Information Systems from the viewpoints of climatology, geography, disaster science, and environmental science and so on. Using natural disaster and risk assessment theory, a multi-dimensional grassland fire risk index (MGFRI) was proposed by integrating weighted comprehensive method, analytic hierarchy process, and fuzzy gamma method into natural disaster risk index. The developed MGFRI will be an easily understandable tool to manage grassland fire by comparing the risk of regions in the northern China and relative contributions of various factors, for example, hazard, exposure, vulnerability, and management ability. A scale of one to five was derived to measure the risk degree. It shows that 4.4?% of grassland falls in the category of ??very high?? risk, followed by 9.6, 19.1, 60.9, and 5.9?%, respectively, in the categories ??high??, ??middle??, ??low??, and ??very low??. The assessment results show reliability by test. The results in this study are intended to support local, provincial, and national government agencies to: (1) make resource allocation decisions; (2) make high-level planning decisions; and (3) raise public awareness of grassland fire risk, its causes, and ways to manage it.     

The relationship between fire behaviour measures and community loss: an exploratory analysis for developing a bushfire severity scale

Current fire danger scales do not adequately reflect the potential destructive force of a bushfire in Australia and, therefore, do not provide fire prone communities with an adequate warning for the potential loss of human life and property. To determine options for developing a bushfire severity scale based on community impact and whether a link exists between the energy release rate (power) of a fire and community loss, this paper reviewed observations of 79 wildfires (from 1939 to 2009) across Victoria and other southern states of Australia. A methodology for estimating fire power based on fuel loading, fire size and progression rate is presented. McArthur??s existing fire danger indices (FDIs) as well as fuel- and slope-adjusted FDIs were calculated using fire weather data. Analysis of possible relationships between fire power, FDIs, rate of spread and Byram??s fireline intensity and community loss was performed using exposure as a covariate. Preliminary results showed that a stronger relationship exists between community loss and the power of the fire than between loss and FDI, although fuel-adjusted FDI was also a good predictor of loss. The database developed for this study and the relationships established are essential for undertaking future studies that require observations of past fire behaviour and losses and also to form the basis of developing a new severity scale.     

A spatio-temporal analysis of fires in the Southern African Development Community region

Wildfires are considered one of the most common disasters in southern Africa resulting in a high number of human fatalities and financial loss on an annual basis. It is believed that increased population growth, as well as more concentrated settlement planning, is likely to result in increased fire disasters and increased human fatalities as a direct result of wildfires. To better understand the spatial and temporal variations and characteristics of wildfires in the Southern African Development Community (SADC), an 11-year dataset of satellite-derived Active Fire Hotspots was analysed using an open source geographic information system. Results indicate that annual fire frequency for most SADC countries is highly variable. Increasing trends in annual fire frequency were observed in five out of 13 SADC countries with a decrease in annual fire frequency observed in four countries. An additional four countries displayed a somewhat stable trend in fire frequency. Temporally, fires have been observed in all months for the SADC region although distinct fire seasons were observed, largely driven by uni-modal rainfall seasons. The timing, location and strength of rainfall seasons have a marked influence on fire activity depending on the seasonal wet and dry (growing and desiccation) periods. Fire activity in vegetation eco-regions can be attributed to both natural and anthropogenic sources of ignition. However, increased anthropogenic agroforestry activities have resulted in increased fire activity in numerous SADC eco-regions with woodlands, savannahs and montane grassland eco-regions being most prone to wildfires.     

Use of remote sensing-derived variables in developing a forest fire danger forecasting system

Our aim was to develop a remote sensing-based forest fire danger forecasting system (FFDFS) and its implementation in forecasting 2011 fire season in the Canadian province of Alberta. The FFDFS used Moderate Resolution Imaging Spectroradiometer (MODIS)-derived 8-day composites of surface temperature, normalized multiband drought index, and normalized difference vegetation index as input variables. In order to eliminate the data gaps in the input variables, we propose a gap-filling technique by considering both of the spatial and temporal dimensions. These input variables were calculated during the i period and then integrated to forecast the fire danger conditions into four categories (i.e., very high, high, moderate, and low) during the i + 1 period. It was observed that 98.19 % of the fire fell under “very high” to “moderate” danger classes. The performance of this system was also demonstrated its ability to forecast the worst fires occurred in Slave Lake and Fort McMurray region during mid-May 2011. For example, 100 and 94.0 % of the fire spots fell under “very high” to “high” danger categories for Slave Lake and Fort McMurray regions, respectively.     

陇东黄土高原北部全新世野火历史的木炭屑记录

全新世黄土-古土壤剖面保存的木炭屑记录了野火和自然景观演变的过程,本研究通过野外考察采样和磁化率、TOC、木炭屑的实验分析探索陇东黄土高原北部地区全新世野火的历史。研究结果表明:11500aB.P.之前末次冰期,气候干旱,在半荒漠草原植被条件下,自然野火频繁发生;全新世早期（11500～8500aB.P.）野火发生频率大大降低;8500～3100aB.P.为全新世气候适宜期,气候相对比较湿润,生物风化成壤作用强烈,呈现森林草原景观,野火发生几率明显下降,但在古土壤形成早期,木炭屑峰值反映有野火频繁发生,这可能是新石器时代早期老官台文化（8000～7000aB.P.）时期人类用火及其放火烧荒开垦农田等活动的结果;全新世晚期气候向干旱化发展,具有游牧性质的寺洼文化（3250～2650aB.P.）出现在陇东北部黄土高原地区,有一定野火活动。1500aB.P.以后,木炭屑浓度大幅度减少,反映野火很少发生,可能由于本地区半农半牧土地利用方式已经确立,人工-自然复合生态景观形成。     

Fire in a Weichselia-dominated coastal ecosystem from the Lower Cretaceous (Barremian) of the Kurnub Group in NW Jordan

Large intervals of the Cretaceous are considered as a ‘high-fire’ period in Earth's history. However, so far most studies dealing in greater detail with the fossil evidence of palaeo-wildfires, i.e. fossil charcoal, originate from the northern hemisphere (i.e. North America, Europe, Asia) whereas there are large stratigraphic and geographic gaps on the Cretaceous southern continents. The present paper deals with the fossil contents (plant macro-remains, palynomorphs and charcoal) of a lignite lens from the lower part of the Lower Cretaceous Kurnub Group near King Talal Dam in Jordan. The data provide evidence for the repeated occurrence of palaeo-wildfires in coastal ecosystems on the northern margin of Gondwana during the Barremian. The fossil content of the lens indicates that the vegetation, which was repeatedly affected by fire, has been dominated by the matoniaceous tree fern Weichselia reticulata. Palynological data from the lignite, as well as the repeated occurrence of wildfires point to an at least seasonally dry (or at least less humid) climate during deposition of the lignite.     

新生代增温情景下自然火历史的研究

自然火是地球系统的重要组成部分,与气候、植被关系紧密。全球增温情景下,自然火的演化规律和控制因素已经成为学术界的研究热点,通过整理分析自然火实际监测记录、模型模拟结果以及古记录反映的自然火历史,发现还存在一些亟待解决的问题:全球不同增温情景下自然火增多还是减少?其控制因素如何改变?本文选取距今最近的地质历史时期新生代中的典型增温期"中中新世气候适宜期"和"全新世大暖期",对其自然火研究进行分析总结,归纳得出温度是增温情景下自然火的重要控制因素,但是不同地区自然火控制因素有所不同,雨热条件的季节分配、植被类型的演替、雷电和火山活动等因素也对自然火有重要影响。季风区气候变幅大、植被类型丰富,其自然火演化及控制因素具有复杂性,是自然火研究的重要区域,建议在今后研究中,在东亚季风区选择涵盖未来百年可能增温幅度的理想沉积记录,对其记录的自然火历史、增温幅度、植被演替进行系统研究,进而探讨未来增温情景下自然火的演化规律和控制因素。     

Repeated Wildfires in the Middle Jurassic Xishanyao Formation (Aalenian and Bajocian Ages) in Northwestern China

The coal-bearing strata in the southern Junggar Basin in northwestern China have recently attracted the attention of coal geologists. Its abundance of coal resources is of great interest as there is a potential of unlocking details about the palaeoclimatic information. Coal deposits have the capacity to record wildfire events, even those with inefficient combustions. To characterize wildfire events and palaeoclimatic history of the Middle Jurassic Xishanyao Formation (Aalenian and Bajocian ages), 22 coal samples from borehole cores and coal mines in the southern Junggar Basin were collected and their macerals were analyzed. The results indicated that fusinite and semi-fusinite were the dominant components of inertinite with proportions of 35.27% and 54.67%, respectively. The presence of inertinite is an indicator that wildfires occurred at the time of peat land development, and the widespread occurrence suggests large scale wildfires during the Middle Jurassic. This study proposes a new parameter for the evaluation of wildfire features by combining burning frequency and burning temperature. The comprehensive evaluation index (CEI) was influenced by the lacustrine basin level and ancient plant types from a sequence framework. During the Middle Jurassic, most wildfires were surface fires with low level and ground fire with high level. High oxygen levels were estimated in the lower, middle, and upper members of the Xishanyao Formation with corresponding to 26.78%, 24.55%, and 23.55%, respectively. The high oxygen levels would be the primary cause of repeated wildfires in the Middle Jurassic. These results are helpful for understanding palaeoclimatic changes in the Middle Jurassic.     

GIS-based evolutionary optimized Gradient Boosted Decision Trees for forest fire susceptibility mapping

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.     

中国北方沙尘灾害影响因子分析

利用中国北方1951—2000年188个沙尘暴代表站的气象观测数据和1983—2000年EROS数据中心NDVI数据,对我国北方沙尘灾害的影响因子进行了分析。主要结论有：①在影响沙尘暴发生、发展、演化的自然因子中,植被覆盖度、降水、大风日数和温度起关键作用,夏季植被覆盖度对来年春季沙尘暴发生频次影响较大,降水和温度主要表现在对地表植被覆盖等与沙尘暴有关的地表参数的影响;②大风日数和温度是沙尘暴形成的动力因子,植被覆盖度和降水是阻力因子。沙尘暴日数和持续时间的变化,主要取决于动力因子与阻力因子的综合作用;③遏制沙尘灾害的治本办法,不在于治理沙尘暴本身,而在于消除产生土地退化、生态安全下降的社会原因,处理好发展与生态环境建设的关系。     

Monitoring Forest Fire Danger with Remote Sensing

Our paper presents a review of the use of remote sensing technologies for forest wildfire danger monitoring, with a particular emphasis on its applicability to fuel moisture monitoring. Remote sensing of fuel moisture was first done with NOAA-AVHRR NDVI images, but NDVI is more related to vegetation greenness rather than water stress. NOAA-AVHRR surface temperature images were also used, alone or in association with NDVI images. Both kinds of images have a limited image availability due to cloud cover. This is not the case for radar images, but their use in fuel moisture monitoring is still experimental, because of the noisy effects of several factors. Finally, the paper discusses the operational potentials and limitations of the use of each kind of satellite data for fire danger monitoring.     

地球排气与森林火灾和地震活动

地球不仅是固体 ,而且充满了流体。当地球受力时 ,地壳变形和破裂 ,气体 (H2 ,CH4 ,CO等 )从内向外溢出 ,这样可引起森林火灾和地震。自 1990— 2 0 0 0年 12月利用卫星热红外图像资料做地震短临震兆的观察取得了突破性进展。正式预测、预报 149次 ,10 0次有结果 ,虚报 49次。 10 0次有结果的预测、预报中较准确的有 6 5次 ,含 7级地震 10次、6级地震 19次、5级地震 36次。较好预报有 2 5次 ,含 7级地震 4次。较差预报有 10次。由于云层干扰有 49次虚报和 2 0次漏报。 1998年 5月 13日— 5月 2 2日内蒙古大兴安岭阿尔山森林火灾前 10d ,即 1998年 5月 4日在卫星热红外云图上见到内蒙古大兴安岭阿尔山森林区出现圆形排气增强区。 1999年 4月 3日山西汾阳森林火灾前 4d ,即 1999年 3月 31日卫星热红外云图上汾阳森林区出现一孤立圆形排气增温区。 2 0 0 0年 3月 2 8日福州郊外森林区起火 ,就在当日卫星热红外云图上可见到福建沿海大陆升温。 1996年 9月 6日台湾兰屿发生 7 1级地震 ,地震前 11d增温震兆呈现一个奇特构造应力热体系———山字型。     

Long-term Trends in Vegetation Dynamics and Forest Fires in Brandenburg (Germany) Under a Changing Climate

The human influence on environmental processes has been described for many types of land use. One of the oldest tools to modify people’s environment is fire, which has dominated fire regimes in many regions over long time scales. This paper focuses on a German case study region, where 80–90% of the fires are human-caused. The objectives of this study are the application of the Regional Fire Model (Reg-FIRM), a process-based fire model that is incorporated into the LPJ Dynamic Global Vegetation Model, to temperate forests under historic climate conditions and to explore ranges of potential impacts of future climate change on fire and vegetation dynamics. Simulation experiments are designed to simulate historic fire pattern and to explore influences of vegetation on fire. Simulated fire pattern reproduced the observed average fire conditions reasonably well although with a smaller amplitude. This leads to underestimation of extreme fire years as well as an overestimation of low fire years. Vegetation composition influenced fire spread conditions in the temperate forest and had little impact on fire ignition potentials, except when only broad-leaved deciduous forests were assumed. Fire is likely to change under climate change conditions. Simulated experiments were conducted to explore the effects of climate change and rising CO₂ concentration given the potential natural vegetation as the best-case for Brandenburg. Three GCM scenarios predicting different future climatic changes were applied, and resulted in quantitatively different future fire patterns. Depending on future precipitation pattern and the influence of the CO₂ effect on canopy conductance and thus litter moisture, fire was predicted to either decrease or slightly increase in Brandenburg forests, but the burnt area would not exceed current, extreme fire years. Generally, fire changes had no implication for vegetation composition in Brandenburg, but reduced vegetation carbon gain after 2050. In the HadCM3 application, simulated increase in grass cover due to a large burnt area after 2075 accelerated fire spread conditions, thus still increasing the burnt area, while climatic fire danger and number of fires already began to decline. These interactions underline the importance to consider the full range of fire processes and interactions with vegetation dynamics in a simulation model.     

Assessing vegetation dynamics in the Three-North Shelter Forest region of China using AVHRR NDVI data

The Three-North Shelter Forest Programme (TNSFP) covers 551 Chinese counties and an area of 4,069,000 km² mostly in arid and semi-arid regions. In this paper, we discuss the temporal and spatial changes in value of the normalized-difference vegetation index (NDVI) in this region, and the relationships between NDVI and climatic factors (temperature and precipitation) based on NOAA Advanced Very High Resolution Radiometer Global Inventory Modeling and Mapping Studies NDVI data with 8-km resolution from 1982 to 2006. During the past 25 years, the vegetation cover has generally increased in eastern regions of China and the oasis in the north piedmont of Tianshan Mountains, but has decreased northwest of Xinjiang and in the Hulunbeier Plateau. The multi-year monthly average NDVI distribution map showed that NDVI increased from April to August, but in the western and northern plateau areas, the lower temperatures and high altitude created a shorter growing season (1 or 2 months). The vegetation of the study area has generally increased in the regions covered by the TNSFP. Linear regression analysis of the vegetation cover showed an increasing trend over large areas. The largest annual growth rate per pixel (the slope of the regression) was 0.009; the largest negative annual change was −0.004. The correlation between NDVI and precipitation was higher than that between NDVI and temperature, suggesting that precipitation is the most important factor that affects NDVI changes in the study area, especially for temperate desert vegetation in northwestern China.     

全球变化下北方农牧交错地带区域适应能力评价模型研究

以可持续发展理论为指导,依据2006年全球变化人类行为计划（IHDP）第六届开放会议精神,参考前人有关生态环境评价框架和指标组合研究,建立了适合北方农牧交错地带特点的区域适应能力评价模型（PSR-RAD）,并对模型的构建思想、参数意义和评价指标的具体计算进行了探讨,以期为全球变化区域响应研究提供参考。针对北方农牧交错地带的实际情况,PSRRAD模型将第四纪地质地貌与现代生态环境研究整合,提出第四纪地质脆弱指数概念,在生态环境胁迫分析中,提出衡量农牧交错地带农牧业环境胁迫程度的地农牧业生产量指数的概念,使生态环境先天与后天胁迫因子、自然与人文因子得以客观体现,对生态环境脆弱性研究的时间和空间尺度均有所拓展。     

中国东北样带NDVI的季节变化及其与气候因子的关系

NDVI是研究大尺度生态学问题一个非常有用的指数,它可以为估价全球植被动态模型提供足够的信息.中国东北样带是全球变化研究中首选样带之一,本文分析了分辨率为1km×1km的NDVI年内季节变化的两个特征值:年均NDVI(NDVI-I)和NDVI年内极差(NDVI-MM)在样带内5种不同植被类型间的变化及其与年平均气温和降水量之间的相关关系.结果表明,NDVI具有明显的季节变化格局,NDVI-I和NDVI-MM由东到西均呈下降趋势,NDVI-I与降水量具有显著的线性回归关系,降水量能够解释NDVI-I和NDVI-MM空间变异的绝大部分.这一结果说明NDVI反映了植被沿环境梯度的时空变化格局,可用于监测样带植被对气候变化的响应.     

Coexisting with wildfire? Achievements and challenges for a radical social-ecological transformation in Catalonia (Spain)

The challenge of sustainability is not about producing more or better managerial knowledge. It is in fact a transformation of the systems and structures that perpetuate environmental problems that is emerging as the key sustainability goal. In this paper we show the relevance of this argument, by using wildfires as symptoms of the challenges posed by global change to western societies, where wildfires are becoming increasingly problematic. Climate change, land abandonment, exurban expansion and fire suppression schemes are some of the main reasons behind this. Tackling the increasing intensity and complexity of wildfires is consequently emerging as an important research and policy topic. A central question in the literature is how to achieve a more sustainable coexistence with wildfire. Fuel reduction treatments, fire restoration, the reform of current suppression policies and adaptive institutional arrangements have all been debated. However, the social-ecological transformations needed to effectively implement these management options are not sufficiently understood. This paper looks at the efforts of the Catalan wildfire management system to cope with wildfire risk over the last decades. In particular, the emergence of GRAF, a group of wildfire fighting specialists in the Fire Department, is described. Emphasizing the need to understand wildfires as an inherent part of Mediterranean ecosystems, the expansion of GRAF highlights how learning to coexist with wildfire in Catalonia has triggered a set of transformative processes in institutional arrangements and power relationships of the wildfire management system. Our data also illustrate how coexisting with wildfire entails a dramatic social-ecological transformation in terms of land-uses, settlement patterns, energy supply systems and social values about wildfires. Moreover, we warn that in the absence of such systemic changes, management improvements might paradoxically reinforce risk. We conclude that wildfire researchers and practitioners should link the proposed management options to a deeper debate on how to produce alternative, less flammable landscapes, as agents of a broader social-ecological transformation to sustainability.     

An ice-core based history of Siberian forest fires since AD 1250

Forest fires play a key role in the global carbon cycle and thus, can affect regional and global climate. Although fires in extended areas of Russian boreal forests have a considerable influence on atmospheric greenhouse gas and soot concentrations, estimates of their impact on climate are hampered by a lack of data on the history of forest fires. Especially regions with strong continental climate are of high importance due to an intensified development of wildfires. In this study we reconstruct the fire history of Southern Siberia during the past 750 years using ice-core based nitrate, potassium, and charcoal concentration records from Belukha glacier in the continental Siberian Altai. A period of exceptionally high forest-fire activity was observed between AD 1600 and 1680, following an extremely dry period AD 1540–1600. Ice-core pollen data suggest distinct forest diebacks and the expansion of steppe in response to dry climatic conditions. Coherence with a paleoenvironmental record from the 200 km distant Siberian lake Teletskoye shows that the vegetational shift AD 1540–1680, the increase in fire activity AD 1600–1680, and the subsequent recovery of forests AD 1700 were of regional significance. Dead biomass accumulation in response to drought and high temperatures around AD 1600 probably triggered maximum forest-fire activity AD 1600–1680. The extreme dry period in the 16th century was also observed at other sites in Central Asia and is possibly associated with a persistent positive mode of the Pacific Decadal Oscillation (PDO). No significant increase in biomass burning occurred in the Altai region during the last 300 years, despite strongly increasing temperatures and human activities. Our results imply that precipitation changes controlled fire-regime and vegetation shifts in the Altai region during the past 750 years. We conclude that high sensitivity of ecosystems to occasional decadal-scale drought events may trigger unprecedented environmental reorganizations under global-warming conditions.