Modeling the spatial patterns of human wildfire ignition in Yunnan province,China

Despite wildfire being an important regulator of dryland ecosystems, uncontrolled wildfire can be harmful to both forest ecosystems and human society, and wildfire prevention and control continue to raise worldwide concern. Wildfire management depends on knowledge of wildfire ignitions, both for cause and location. The regimes and factors influencing wildfire ignition have been studied at length. Humans have a profound effect on fire regimes and human activity is responsible for igniting the largest number of fires in our study area. Understanding the spatial patterns of ignitions is foremost to achieving efficiency in wildfire prevention. Previous studies mainly concentrate on overall wildfire risk integrating numerous factors simultaneously, yet the importance of human factors on ignition has not received much attention. In this study, we mapped human accessibility to explore the influence of human activity on wildfire ignition in a simple and straightforward way. A Bayesian weights-of-evidence (WofE) method was developed based on fire hotspots in China's Yunnan province extracted from satellite images and verified as known wildfires for the period 2007–2013. We considered a set of factors that impact fire ignition as associated with human accessibility: the locations of settlements, roads, water and farmland susceptible to human wildfire ignition. Known points of likely wildfire ignition were selected as training samples and all suspected thematic maps of the factors were taken as explanatory layers. Next, the weights of each layer in terms of its explanatory power were computed and used to generate evidence based on a threshold to pass a statistical test. The conditional independence (CI) of each layer was checked with the Agterberg-Cheng test. Finally, the posterior probability was calculated and its precision validated using samples of both presence and absence by withheld validation data. A comparison of WofE models was made to test the predictability. Results show proximity to villages, roads and farmland are strongly associated with human wildfire ignition and that wildfire more often occurs at an intermediate distance from high-density human activity. The WofE method proved more powerful than logistic regression, improving predictive accuracy by 10% and was more straightforward in presenting the association of dependence and independence. In addition, WofE with 1000 m buffer bands is more robust in predicting human wildfire ignition risk than binary or 100 m buffers for the ecoregion studied. Our results are significant for advising practical wildfire management and resource allocation, evaluation of human ignition control and also provides a foundation for future efforts toward integrated wildfire prediction.     

Human-ignited wildfire patterns and responses to policy shifts

Development of efficient forest wildfire policies requires an understanding of the underlying reasons behind forest fire occurrences. Globally, there is a close relationship between forest wildfires and human activities; most wildfires are human events due to negligence (e.g., agricultural burning escapes) and deliberate actions (e.g., vandalism, pyromania, revenge, land use change attempts). We model the risk of wildfire as a function of the spatial pattern of urban development and the abandonment/intensity of agricultural and forestry activities, while controlling for biophysical and climatic factors. We use a count data approach to model deliberately set fires in Galicia, N.W. Spain, where wildfire is a significant threat to forest ecosystems, with nearly 100,000 wildfires recorded during a thirteen-year period (1999–2011). The spatial units of analysis are more than 3600 parishes. Data for the human influences are derived from fine-resolution maps of wildland–urban interface (WUI), housing spatial arrangements, road density, forest ownership, and vegetation type. We found wildfire risk to be higher where there are human populations and development/urbanisation pressure, as well as in unattended forest areas due to both rural exodus and a fragmented forest ownership structure that complicates the profitability of forestry practices. To better help direct management efforts, parameter estimates from our model were used to predict wildfire counts under alternative scenarios that account for variation across space on future land-use conditions. Policies that incentivize cooperative forest management and that constrain urban development in wildlands at hotspot fire locations are shown to reduce wildfire risk. Our results highlight the need for spatially targeted fire management strategies.     

Spatial Characteristics of Regional Wildfire Frequencies in Intermountain West Grass-Dominated Communities

Understanding the environmental factors that influence spatial patterns of rangeland wildfires facilitates both fire and land management decisions. I used discriminant analysis to examine ignition frequency of lightning-initiated fires in grass-dominated communities in the Intermountain West between 1980 and 1994, then mapped regional fire frequencies to illustrate spatial patterns. Two canonical discriminant functions effectively separate groups of high, medium, and low ignition frequencies, based on climate conditions and fuel characteristics. Regions of highest frequency tend to have large elevational differences, more mesic climates, and less annual grass cover. Spatial patterns of ignition frequencies tend to reflect local topography, with higher frequencies west of 119° W. Expansion of exotic annual grasses throughout the region may be reducing differences in ignition frequency between regions of highest and lowest frequency.     

Fire In The Management Of Vegetation

Abstract

Fire, either natural or man-caused, has influenced the pattern of vegetation in numerous areas over the earth. Factors that contribute to potential damage to either the vegetation and/or environment are examined. Since the extent of damage varies, a fire can be destructive or useful. The use of “prescribed” fire in land management accomplishes several desired objectives, one of which is the perpetuation of certain fire-climax vegetation types, such as pines and some grasses. In those pine-forested areas where fire is regularly used in management, a related benefit is the reduction of hazardous natural fuels, which results in fewer catastrophic wildfires. Air pollution due to forest burning is also considered.     

Reconstructing a cultural fire regime in the Pennsylvania Anthracite Region

Abstract

Fire history reconstructions provide fire managers with valuable information regarding historical fire regime dynamics. Yet, in the Central Hardwood Forest Region (CHF), there is an absence of dendroecological studies where frequent wildfires have persisted into the twenty-first century. This study presents the first documented tree-ring reconstruction of fire history in the Pennsylvania anthracite coal-producing region. An approximately 150-year fire chronology was developed from fire-scarred pitch pine (Pinus rigida) and sassafras (Sassafras albidum) collected on Spring Mountain in Schuylkill County. Principal component analysis and k-means cluster analysis were used to identify four fire regime clusters based on interacting fire and non-fire parameters. Results indicate that fires occurred under a variety of moisture conditions and that a mid-twentieth century increase in fire activity on Spring Mountain was associated with the collapse of the regional anthracite industry and possibly amplified by the 1960s drought. Fires continue to burn on Spring Mountain in the twenty-first century, contrary to the dominant pattern of fire exclusion across the CHF. Future research needs are highlighted regarding historical fire regime dynamics and cultural ties to landscape burning in the Pennsylvania Anthracite Region.     

蒙古东部野火时空格局及其影响因素

基于MCD64A1过火迹地产品、土地覆盖、植被指数和气候等数据,采用空间统计分析和相关分析方法研究了2001—2017年蒙古东部野火时空动态及其影响因素。结果表明：（1）4—6月是野火发生最主要的时段,10月野火灾害也较严重,特别集中于年内第107—127、145—189、279—301日3个时段;2001—2017年,蒙古东部野火过火面积年际间波动较大,2003、2007、2011、2012、2015年是野火发生的高峰年。（2）从野火发生的空间格局看,野火灾害主要发生在东方、肯特、苏赫巴托尔、色楞格、中央省;草原火是蒙古东部主要的过火类型。（3）过火面积主要受降水、温度和植被状况影响;3月过火面积主要与3个月累积的干旱状况有关,而6、7月过火面积主要与当月温度相关,9月过火面积主要受当月降水量影响;在季节尺度上,春季过火面积还与前一年秋季植被状况显著相关,冬季过火面积与当季地表温度呈显著正相关。（4）大气环流与蒙古东部的野火发生、蔓延密切相关,4月过火面积主要受3个月累积北极涛动影响,7月过火面积主要受3个月累积太平洋十年涛动影响,9月过火面积主要受火前北大西洋涛动影响,而11月过火面积主要受3个月累积南方涛动和太平洋十年涛动影响。年尺度上的过火面积主要受北大西洋涛动显著影响。     

Integrating Fire Behavior and Pedestrian Mobility Models to Assess Potential Risk to Humans from Wildfires Within the U.S.–Mexico Border Zone∗

Wildfires create a risk to pedestrians traveling through rural areas, because they might not be aware of the presence of a wildfire or its direction and rate of spread until is too late to successfully evacuate. In wildland areas of southern San Diego County, immigrants crossing the U.S.–Mexico border and border security agents are particularly at risk to wildfires. The objective of this study is to develop a framework of analysis and associated tools for examining the combined behavior of wildfires and pedestrian mobility to assess the potential threat of fire to pedestrians in wildland areas. Outputs from a geographic information system (GIS) overlay model for determining potentially dangerous fire zones, the Wildland–Urban Interface Evacuation (WUIVAC) model, and a model of pedestrian mobility in wildland areas were combined to generate wildfire risk to pedestrian maps. The key technical contributions of the study are the development and testing of the pedestrian mobility model and the framework and logic for integrating the results of three GIS-based models. The applied geography contribution is the testing of two scenarios of high risk from wildfires to pedestrians within the U.S.–Mexico border zone of San Diego County, California.

The study results show that the travel times calculated by the pedestrian mobility model appear to be realistic and are affected by the terrain and vegetation characteristics of a study site, whereas the evacuation trigger buffers (ETBs) from WUIVAC are mostly influenced by the wind speed and direction parameters of the FlamMap fire spread model. A moderate fire danger to pedestrians in the most remote wildland locations of the study area is determined. The scenario test results suggest that if a wildfire occurs within 2 km (extreme southwesterly winds) or 6 km (extreme northeasterly wind) of pedestrians in the worst case location within the San Diego border region they would likely not have a sufficient amount of time to reach a nearby safety zone.     

“Playing With Fire” in a Pre-Election Period: Newspaper Coverage of 2007 Wildfires in Greece

Newspaper coverage of 2007 wildfires in Greece was examined within a pre-election period. Interpretative repertoires are presented that were employed by two newspapers, each aligned to one of the two leading parliamentary parties at that time. Media discourse was framed within the emergency character of the fire suppression paradigm, while fire was mistreated as unexpected and “unnatural,” namely, not integral to Mediterranean ecosystem dynamics. Depiction of the government focused on dealing with fire episodes and was marked by newspaper partisanship. This might have obscured the responsibility of political leadership to account for long-term rural socioeconomic trends, such as agricultural abandonment and rural depopulation, which might have added to fire hazard. Newspaper content was marked by the interpretative repertoire of “asymmetric threat,” launched by the government to shape wildfires as the result of a supposed conspiracy plan and, thereby, to overcome blame for its failures.     

UK-based terrorists' antecedent behavior: A spatial and temporal analysis

Background and purposeTerrorism is a real and present danger. The build-up to an attack includes planning, travel, and reconnaissance which necessarily require the offender to move through their environment. Whilst research has examined patterns of terrorist attack locations, with a few exceptions (e.g. Rossmo & Harries, 2011), it has not examined the spatial behavior of the terrorists themselves. In this paper, we investigate whether the spatial mobility patterns of terrorists resemble those of criminals (and the wider population) and if these change in the run up to their attacks.MethodUsing mobile phone data records for the ringleaders of four different UK-based terrorist plots in the months leading up to their attacks, we examine the frequency with which terrorists visit different locations, how far they travel from key anchor points such as their home, the distance between sequential cell-site hits and how their range of movement varies as the planned time to attack approaches.ConclusionsLike the wider population (and criminals), the sample of terrorists examined exhibited predictable patterns of spatial behavior. Most movements were close to their home location or safe house, and they visited a relatively small number of locations most of the time. Disaggregating these patterns over time provided mixed evidence regarding the way in which their spatial activity changed as the time to the planned attack approached. The findings are interpreted in terms of how they inform criminological understanding of the spatial behavior of terrorists, and the implications for law enforcement.     

Spatial patterns and drivers of fire occurrence in a Mediterranean environment: a case study of southern Croatia

Wildfires are an important factor of landscape dynamics in fire-prone environments of the world. In the Mediterranean, one of the most fire-susceptible environments globally, between 45,000 and 50,000 wildfires are recorded every year, causing disturbances in forest and grassland ecosystems. As a Mediterranean country, Croatia faces these problems, averaging over 1000 registered wildfires annually, with the coastal areas dominated by forest fires and continental Croatia by fires on agricultural lands. This research combines various landscape and socio-economic factors in the analysis of fire occurrence in Croatia’s southernmost region of Dalmatia. Around 275 of the largest fires (encompassing 98% of the total burnt area) registered in 2013 were investigated using OLS, and different spatial indices were employed to analyse regional variability in fire distribution. The results revealed that areas more prone to fires are the northern inland areas of Dalmatia and its entire coastal zone. Altitude and vegetation type demonstrated a correlation with fire occurrence, but an increase in population in the study area was also correlated with wildfire occurrence. Regarding vegetation, the grasslands and Mediterranean shrubland (maquis) were found to be the most fire-prone vegetation types in the study region, the distribution of which can be linked to different socio-economic and demographic processes occurring in the Eastern Adriatic.     

基于土壤水分和气象要素的林火预报研究——以广东省为例

基于国内现行的森林火险气象指数和单因子火险贡献度模型,以及逻辑回归模型和随机森林模型,在林火预报中引入微波遥感土壤水分信息,使用MCD14DL火点数据集和地面气象观测资料对广东省不同时间尺度的林火发生概率进行预测。结果表明：逻辑回归模型和随机森林模型构建的林火预测模型显著优于现行的森林火险气象指数和单因子火险贡献度模型,预测精度提升约20%。其中,随机森林模型对林火频数的解释程度最高（两者相关系数为0.476）。此外,加入微波土壤水分信息后,相较原有的基于气象要素的林火预测模型,2种机器学习模型的预测精度均略有提升,体现了表层土壤水分信息在林火预报中的重要性。研究可为高效提取对地观测信息,以改进华南地区不同时间尺度的林火预报工作提供参考。     

The importance of Swedish–Norwegian border residents’ perspectives for bottom-up cross-border planning strategies

ABSTRACT

There is political interest in Sweden’s proximity to Norway, which is reflected in the regional policy focusing on developing business needs. As such, proximity at the regional level is simply expected to generate economic growth. The authors propose a holistic approach to spatial planning in a Swedish–Norwegian border region in place of the simplistic economic perspective. The aim of the article is to highlight the importance of adopting a bottom-up cross-border planning perspective that is based on the perceptions of the border region residents by showing that the proximity of Norway is important to communities in Värmland Province, on the border with Norway, in a different way from how regional authorities and policymakers perceive it. The authors used a qualitative method in their study. They found that residents were more interested in the individual, social, and cultural opportunities of the border, while authorities stressed traditional growth strategies. In conclusion, the authors recommend that policymakers should implement a bottom-up cross-border planning strategy (CBPS) in Värmland that includes the residents’ perspective, as a reinforcement of place-based policy approaches.     

Effects of fire and environmental variables on plant structure and composition in grazed salt desert shrublands of the Great Basin (USA)

Fire in shrub-dominated portions of the Great Basin, largely fueled by non-native annuals such as Bromus tectorum, has become an important structuring force altering vegetation composition and soil characteristics. The extent to which fire affects native species in drier portions of the Great Basin, termed salt desert, is poorly documented. We conducted a survey of grazed salt desert habitat in northwestern Nevada 5 years after wildfires burned 650,000 ha, with the goal of investigating community response to fire and factors correlating with post-fire recovery. We found that recruitment of a dominant shrub, Artemisia spinescens, is severely restricted following fire: it occurred in only 2 of the 24 burned sites. The co-dominant shrub, Atriplex confertifolia, occurred in most burned sites although on average its percent cover was one-third lower than adjacent unburned sites. Biotic soil crust cover was four times lower, and non-native species cover 5 times higher, in burned sites compared to unburned. Ordination analyses confirmed differences among plant communities in burned versus unburned sites, with environmental variables soil conductivity, plant litter, soil potassium (K⁺) and pH explaining 38% of the variance in community composition. However, we found no environmental predictors of recovery for native species in burned sites. Future recruitment is likely to be further limited, as fire frequency in the salt desert is expected to increase with invasion by non-native annual grasses and with global climate change.     

Vegetative succession and controlled fire in a glades ecosystem A geographical information system approach

Abstract

A geographical information system (GIS) approach was used successfully on a federal wilderness area in southwestern Missouri to examine vegetative succession relative to fire management in a glades ecosystem. Maps of vegetation were obtained by interpreting aerial photographs taken in 1938, 1958, 1966, 1975 and 1986. Maps of topography, streams, soils and the location of fires which burned during the period 1938 to 1986 were also procured from a variety of public agencies. All maps were digitized and incorporated into a raster-based GIS with 25 m pixels. It was concluded that (1) both glades and oak-hickory forest have an affinity for distinct physiographic areas and (2) fire can help decrease the rate of processes of natural succession which cause glades to convert to forest. The probable effects of controlled fire on three areas proposed by the Forest Service were evaluated and summarized.     

Annual growth zones in stems of Hypericum irazuense (Guttiferae) in the Costa Rican páramos

The high peaks of the Cordillera de Talamanca in Costa Rica support shrub- and grass-dominated páramo ecosystems that experience stand-replacing wildfires. The dry season that facilitates these fires results in dormancy in plant growth and provides an opportunity to use dendrochronological analyses to determine ages of plants in burn sites to support studies of fire history and postfire vegetation recovery. This study investigates the formation of annual growth zones in stems of the common shrub Hypericum irazuense. Unlike other páramo shrubs, H. irazuense rarely resprouts following fire, instead recovering through seedling recruitment following seed dispersal from the unburned periphery. Laboratory analysis of 19 prepared cross sections from 15 stems shows that samples of H. irazuense from burned areas can provide an estimate of the minimum number of years since the previous fire, supporting earlier work based on field examination of stems. Including a time lag for seedling recruitment or resprouting refines that estimate. Counts of growth zones in most sections coincided with dates of the last known fires. The presence of annual growth zones in H. irazuense places the species within a relatively small group of woody Neotropical species for which annual rings or growth zones have been demonstrated.     

A Review of “The Power of Place”

Two qualitative case studies, one focusing on K-12 teachers and the other on middle school students, explore key factors associated with using Geographic Information Systems in the classroom. In both studies, access to appropriate hardware is a critical barrier. Time is another critical barrier—time to learn the GIS software and time in the curriculum to incorporate GIS as a learning experience. In both case studies, learning the technology at the expense of learning spatial analysis was a danger, suggesting the need for conscious focus on the goal of using GIS to learn how to “do geography.”     

Estimating spatial efficiency using cyber search,GIS, and spatial optimization: a case study of fire service deployment in Los Angeles County

ABSTRACT

The efficiency of public investments and services has been of interest to geographic researchers for several decades. While in the private sector inefficiency often leads to higher prices, loss of competitiveness, and loss of business, in the public sector inefficiency in service provision does not necessarily lead to immediate changes. In many cases, it is not an entirely easy task to analyze a particular service as appropriate data may be difficult to obtain and hidden in detailed budgets. In this paper, we develop an integrative approach that uses cyber search, Geographic Information System (GIS), and spatial optimization to estimate the spatial efficiency of fire protection services in Los Angeles (LA) County. We develop a cyber-search process to identify current deployment patterns of fire stations across the major urban region of LA County. We compare the results of our search to existing databases. Using spatial optimization, we estimate the level of deployment that is needed to meet desired coverage levels based upon the location of an ideal fire station pattern, and then compare this ideal level of deployment to the existing system as a means of estimating spatial efficiency. GIS is adopted throughout the paper to simulate the demand locations, to conduct location-based spatial analysis, to visualize fire station data, and to map model simulation results. Finally, we show that the existing system in LA County has considerable room for improvement. The methodology presented in this paper is both novel and groundbreaking, and the automated assessments are readily transferable to other counties and jurisdictions.     

河南省火灾影响因素的空间分析

科学揭示火灾及其影响因素间的空间关系可为防火管理提供决策支持和有益启示。以往研究多在“空间平稳”的框架下进行火灾影响因素分析,但火灾和其可量化的影响因素往往自身均表现为“空间异质”,基于非空间的全局模型模拟可能会得出误导性甚至错误的结论。地理加权回归(GWR)可解释火灾及其影响因素间空间关系的局部变异。本文选取影响火灾分布的高程、坡度、居民地可达性、道路可达性、地表温度、归一化差植被指数和全球植被湿度指数作为解释变量,以是否火烧作为二元因变量,应用logistic GWR对河南省2002-2012年火季(9-10月)火灾的影响因素进行探索性分析。以多时态空间抽样取得训练样本,利用GWR 4.0软件开发一个logistic GWR火烧概率模型,从可靠性和区分能力两方面对模型性能分别进行内部检验和独立检验,以确保火灾影响因素分析的可靠和合理性。结果表明:①坡度、居民地可达性、温度、植被长势和植被湿度对河南省火灾的影响呈现显著空间变化,高程、道路可达性的影响空间变化不显著,低海拔、道路可达性差的区域更易发生火灾。②温度和植被长势对火灾影响省内全局显著,坡度、居民地可达性和植被湿度对火灾影响在省内仅部分区域显著。③河南省可划分为7种类型区,不同类型区的火灾影响因素相对重要性存在差异,应因地制宜制定防火策略和确定防火重点。④logistic GWR模型可用于分析火灾影响因素的局部空间变异,作为火险研究的一种有效工具。     

Regularities in Spatial Information Processing: Implications for Modeling Destination Choice

This paper investigates the determinants of spatial knowledge and how our knowledge of space varies according to geographic location. By using data on U.S. city names recalled at 22 test locations, a multivariate model of the information surface specific to each test location is calibrated. This model links the probability of a city being recalled from memory to its distance from the test site, its population size, its location with respect to other cities, and whether or not it is a state capital. The paper then suggests that these recall data provide information on spatial knowledge surfaces from which large-scale spatial choices, such as migration destinations, are made. Results from the analysis lend further evidence to the idea that spatial knowledge is stored and processed hierarchically and that individuals underrepresent information in large clusters. Consequently, the results have important implications for modeling any spatial behavior based on individuals' spatial information surfaces. In particular, the results cast further doubt on the validity of traditional large-scale spatial choice frameworks and lend support to the competing destinations hypothesis.     

伊洛河流域森林景观变化驱动因素

1 Introduction Landscapes are the outcome of the interaction between socio-economic and natural forces (Wrbka et al., 2004). During the evolution of cultural landscapes throughout the world, human activities have become dominant factors shaping most lands…