Wildfire Incident Research Articles

Playing with fire: Socioeconomic factors and deliberate wildfires in Texas

Deliberately setting fires, also known as arson, is one of the primary causes of human-caused wildfires in the US. Arson fires pose a significant threat, contributing to the human-caused wildfire problem in the southern US. Since more than 90% of wildfires in the South are human-caused, it is particularly important to examine the factors that influence the distribution of arson wildfires in this region. While most research has combined arson fires together with other human-caused wildfires, a smaller body of studies has focussed specifically on fires started by arson. The focus of this study is to understand the key factors associated with the distribution of intentional wildfires in Texas. We examine the relationship between a combination of key socioeconomic factors and environmental factors and, arson wildfires using Negative Binomial models. As expected, our results indicate that road density, unemployment rate, and crime rate are positively associated with arson fires, and the number of law enforcement officers and wage rate are negatively associated with arson wildfire incidences. The higher percentage of forest cover in a county and higher temperature regimes are also positively associated with arson fire occurrences. As such, we conclude that arson wildfires are more likely in areas with high accessibility to wildlands. Similarly, counties with high unemployment rates and consequently high crime rates are more likely to suffer from arson wildfires. Our results clearly show that a higher presence of law enforcement officers in a county deter arsonists. Similarly, financial well-being as indicated by the higher wage rates in a county plays an apparent role in curbing arson wildfire occurrences. Thus, the results from this study provide valuable insights to policymakers, land managers, and fire prevention specialists to develop targeted interventions aimed at reducing arson risk in Texas and beyond.

Wildfire-vegetation relationship under ecosystem conditions: a case study of Sirjan plain watersheds’ wildfire incidences in Kerman province, Iran

Wildfire-vegetation relationship under ecosystem conditions: a case study of Sirjan plain watersheds’ wildfire incidences in Kerman province, Iran

The role of radio, television and mobile phones in disseminating information on occurrences of wildfire in Uluguru Mountains Nature Reserve – Morogoro Tanzania

This study sought to determine the contribution of radio, television and mobile phones used by local communities in disseminating and accessing information about wildfire hazards in the Uluguru Mountains Nature Reserve and assessed the extent of their usage in disseminating wildfire information. It also aimed at identifying barriers to their use in reporting wildfire incidences in the Uluguru Mountains and determined the available wildfire reduction strategies which can be improved by use of other types of ICTs. A descriptive survey method and purposive and conveniently sampling techniques were employed to select a sample of 15 key informants and 90 villagers from the three villages that were purposively selected. Questionnaires, focus group discussions, interview with key informants and participants observations were used to collect both quantitative and qualitative data. The finding show that the community living around Uluguru Mountains Nature Reserve own Radio and mobile phones although few of them owned televisions. Very few respondents reported wildfire incidence using their mobile phone, while the majority used their mobile phone for other social-economic activities. However, internet based AFIS Meraka system and handheld GPS were the most common technologies used to disseminate wildfire information. In general radio, mobile phones and televisions are not fully beneficial to the local communities. Based on the results, it was recommended that the role of modern ICTs in detecting and disseminating wildfire be encouraged among the authorities.

Characterization of inhalation exposures at a wildfire incident during the Wildland Firefighter Exposure and Health Effects (WFFEHE) Study.

Wildland firefighters (WFFs) are exposed to many inhalation hazards working in the wildland fire environment. To assess occupational exposures and acute and subacute health effects among WFFs, the wildland firefighter exposure and health effects study collected data for a 2-year repeated measures study. This manuscript describes the exposure assessment from one Interagency Hotshot Crew (N = 19) conducted at a wildfire incident. Exposures to benzene, toluene, ethylbenzene, xylene isomers, formaldehyde, acetaldehyde, and naphthalene were measured through personal air sampling each work shift. Biological monitoring was done for creatinine-adjusted levoglucosan in urine pre- and post-shift. For 3 days sampling at the wildfire incident, benzene, toluene, ethylbenzene, xylene isomers (m and p, and o) exposure was highest on day 1 (geometric mean [GM] = 0.015, 0.042, 0.10, 0.42, and 0.15 ppm, respectively) when WFFs were not exposed to smoke but used chainsaws to remove vegetation and prepare fire suppression breaks. Exposure to formaldehyde and acetaldehyde was highest on day 2 (GM = 0.03 and 0.036 ppm, respectively) when the WFFs conducted a firing operation and were directly exposed to wildfire smoke. The greatest difference of pre- and post-shift levoglucosan concentrations were observed on day 3 (pre-shift: 9.7 and post-shift: 47 μg/mg creatinine) after WFFs conducted mop up (returned to partially burned area to extinguish any smoldering vegetation). Overall, 65% of paired samples (across all sample days) showed a post-shift increase in urinary levoglucosan and 5 firefighters were exposed to benzene at concentrations at or above the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit. Our findings further demonstrate that exposure to inhalation hazards is one of many risks that wildland firefighters experience while suppressing wildfires.

Machine learning framework for Hazard Extraction and Analysis of Trends (HEAT) in wildfire response

This research proposes a natural language processing enabled risk analysis framework, named Hazard Extraction and Analysis of Trends (HEAT), and applies the framework to the ICS-209-PLUS data set of wildfire incident response forms. The HEAT framework produces safety- and risk-relevant analyses, consisting of: (1) a set of hazards extracted from text data, (2) a primary analysis using hazard-relevant metrics, such as rate and severity, to form an FMEA-style table and risk matrix, (3) a time series analysis of metric trends, and (4) a secondary analysis examining potential predictors for hazards. Results from HEAT provide quantitative risk-relevant information for high-level hazards documented in existing-state operations. Because of the generalizability of the steps and limited data requirements, HEAT can be applied to any dataset containing narrative text, thus providing a framework for data-driven machine learning-enabled quantitative risk analysis across a variety of domains. To demonstrate HEAT in a case study, we apply the framework to the ICS-209-PLUS dataset of wildland fire incident response forms. Hazards identified in wildfire response arise from environmental conditions, the mission, and the wildland urban interface. The resulting risk matrix identifies evacuations as high-risk hazards, while all other identified hazards are medium or serious risk.

Spatial Dependencies and Neighbour Interactions of Wildfire Patterns in Galician Mountain Areas (NW Spain)

Galicia is the Spanish region most affected by wildfires, and these wildfire patterns are the object of intense research. However, within Galicia, the mountain areas have certain socioeconomic and ecological characteristics that differentiate them from the rest of the region and have thus far not received any specific research attention. This paper proposes an analysis of the spatial wildfire patterns in the core Galician mountain systems in terms of the frequency, ratio of affected area, suppression time, and extension. The contiguity relations of these variables were examined in order to establish neighbour interactions and identify local concentrations of wildfire incidences. Furthermore, a spatial econometric model is proposed for these dependent variables in terms of a set of land cover (coniferous, transitional woodland–shrub) and land use (agricultural, industrial), complemented by population density, ecological protection, and common lands. The relevance of these parameters was studied, and it was found amongst other results, that economic value (agricultural and/or industrial) mitigates wildfire risk and impact, whereas ecological protection does not. In terms of land cover, conifers reduce the frequency and affected area of wildfires, whereas transitional land has a mixed effect, mitigating suppression time and extension but increasing the wildfire frequency. Suggestions for policy improvements are given based on these results, with a particular emphasis on the need for coordination of local policies in order to take into account the neighbour dependencies of wildfire risk and impact.

A National Map of Snag Hazard to Reduce Risk to Wildland Fire Responders

Falling trees and tree fragments are one of the top five causes of fatalities for wildland fire responders. In six out of ten recent years, at least one fatality from a tree strike has occurred while a fire responder was on duty, and others were injured. We used TreeMap, a national map of forest characteristics, including individual tree height, diameter, and status (live or dead), to generate a map of snag hazard for forested areas of the continental U.S. at 30 × 30 m resolution. Snag hazard was classified into categories of low, moderate, high, or extreme based on snag density and height. Within-class accuracy was as high at 86%, suggesting that the Snag Hazard map can help wildland fire managers identify and avoid exposing fire responders to hazardous conditions. Accuracy was higher outside recently disturbed areas (88%) than inside (79%), perhaps reflecting strong spatial patterns and heterogeneity of mortality within disturbed areas. The Snag Hazard map is a frequently requested product from the Forest Service’sRisk Management Assistance Group. The goal of RMA is to provide analytics to decision makers and fire leadership to facilitate risk-informed decision-making to improve safety, effectiveness, and outcomes. We present a case study showing how the Snag Hazard 2016 map was used to inform fire responders during an active wildfire incident in California during the 2020 fire season.

Priorities and Effectiveness in Wildfire Management: Evidence from Fire Spread in the Western United States

Costs of fighting wildfires have increased substantially over the past several decades. Yet surprisingly little is known about the effectiveness of wildfire suppression or how wildfire incident managers prioritize resources threatened within a wildfire incident. We investigate the determinants of wildfire suppression effort using a novel empirical strategy comparing over 1,400 historical fire perimeters to the spatial distribution of assets at risk. We find that fires are more likely to stop spreading as they approach homes, particularly when homes are of greater value. This effect persists after controlling for physical factors (fuels, landscape, and weather) using a state-of-the-art wildfire simulation tool. As well, the probability that spread will be halted is affected by characteristics of homes 1–2 kilometers beyond a fire’s edge. Overall, we find that suppression efforts can substantively affect wildfire outcomes but that some groups may benefit more from wildfire management than others.

Effects of African BaP emission from wildfire biomass burning on regional and global environment and human health.

The vegetation burning caused by wildfires can release significant quantities of aerosols and toxic chemicals into the atmosphere and result in health risk. Among these emitted pollutants, Benzo(a)pyrene (BaP), the most toxic congener of 16 parent PAHs (polycyclic aromatic hydrocarbons), has received widespread concerns because of its carcinogenicity to human health. Efforts have been made to investigate the environmental and health consequences of wildfire-induced BaP emissions in Africa. Still, uncertainties remain due to knowledge and data gaps in wildfire incidences and biomass burning emissions. Based on a newly-developed BaP emission inventory, the present study assesses quantitatively the BaP environment cycling in Africa and its effects on other continents from 2001 to 2014. The new inventory reveals the increasing contribution of BaP emission from African wildfires to the global total primarily from anthropogenic sources, accounting for 48% since the 2000s. We identify significantly higher BaP emissions and concentrations across sub-Saharan Africa, where the annual averaged BaP concentrations were as high as 5-8ng/m3. The modeled BaP concentrations were implemented to estimate the lifetime cancer risk (LCR) from the inhalation exposure to BaP concentrations. The results reveal that the LCR values in many African countries exceeded the acceptable risk level at 1×10-6, some of which suffer from very high exposure risk with the LCR>1×10-4. We show that the African BaP emission from wildfires contributed, to some extent, BaP contamination to Europe as well as other regions, depending on source proximity and atmospheric pathways under favorable atmospheric circulation patterns.

Resilient Operation of Electric Power Distribution Grids Under Progressive Wildfires

Wildfires have been growingly recognized as a prominent threat in regions with high temperatures during the summer. Power distribution systems, especially those passing through forest regions, are exposed and highly vulnerable to wildfires. This article provides a general formulation to enhance the operational resilience of power distribution networks equipped with renewable energy resources, e.g., wind and solar energy, micro turbines as well as energy storage systems when exposed to progressive wildfires. The wildfire incident is characterized comprehensively and the dynamic heat balance equations of power distribution branches are used to model the impacts of wildfires on overhead line conductors. A mixed-integer quadratic optimization formulation is applied to optimally operate and coordinate all local energy resources to reduce load outages and enhance the system resilience. The applied framework is evaluated on the IEEE 33-node test system. Comprehensive sensitivity analyses are conducted to assess the efficacy of the applied framework, where the numerical results reveal the resilient operation of power distribution networks in the face of wildfire emergencies.

Medical Care at California Wildfire Incident Base Camps.

The California Emergency Medical Services Authority manages and deploys California Medical Assistance Teams (CAL-MAT) to disaster medical incidents in the state. This analysis reviews diagnoses for ambulatory medical visits at multiple wildland fire incident base camp field sites in California during the 2020 fire season. Clinical data without personal health information were extracted retrospectively from patient care records from all patients seen by a provider. Results were entered into Excel spreadsheets with calculation of summary statistics. During the 2020 fire season, CAL-MAT teams deployed 21 times for a total of 327 days to base camps supporting large fire incidents and cared for 1756 patients. Impacts of heat and environmental smoke are a constant factor near wildfires; however, our most common medical problem was rhus dermatitis (54.5%) due to poison oak. All 2020 medical missions were further complicated by prevention and management of coronavirus disease (COVID-19). There is very little literature regarding the acute medical needs facing responders fighting wildland fires. Ninety-five percent of clinical conditions presenting to a field medical team at the wildfire incident base camp during a severe fire season in California can be managed by small teams operating in field tents.

Supporting Wildfire Response During a Pandemic in the United States: the COVID-19 Incident Risk Assessment Tool

The onset of the global pandemic in 2020 significantly increased the complexity and uncertainty of wildfire incident response in the United States, and there was a clear role for decision support to inform and enhance coordination and communication efforts. Epidemiological modeling suggested the risk of COVID-19 outbreak at a traditional large fire camp could be substantial and supported the broadscale implementation of mitigations, and management of COVID-19 required expanding the response network to interface with entities such as local public health agencies, hospitals, and emergency operations centers. Despite the early issuance of medical and public health guidance to support wildfire management functions under a COVID-19 modified operating posture, an identified gap was a scale- and scope-appropriate tool to support incident-level assessment of COVID-19 risk. Here we review the development and application of a COVID-19 Incident Risk Assessment Tool intended to fill that gap. After prototyping with fire managers and risk practitioners, including early-season use on several incidents, we built an online dashboard that was used operationally throughout the 2020 fire season. We summarize usage statistics, provide some examples of real use on wildfire incidents, and report feedback from users. The tool helped to fill a critical information gap and was intended to support risk-informed decision-making regarding incident logistics, operations, and COVID-19 mitigations.

Peering through the smokescreen of success with ecological fire use: A pilot study of three USFS Regions’ 2018–2019 wildfire seasons

This paper explores current levels of Wildland Fire Use (WFU) as a tool for managing wildfires for resource and ecological benefits. In 2009 new policy guidance for the federal Wildland Fire Policy represented a major advance towards a paradigm shift of ecological fire management by allowing wildfires to be managed for both protection and restoration objectives simultaneously. However, at the same time WFU was eliminated as a distinct category of wildfire incident, and since then, a number of abstract, deliberately vague terms have become common surrogates for WFU. We analyzed suppression documents from wildfires managed by the US Forest Service in three USFS Regions during 2018–2019. Results show that in some USFS Regions there may be more WFU for resource/ecological benefits occurring than is officially acknowledged, obscured by the various euphemisms for WFU that are limiting public recognition of ecological fire management success.

Monetising the savings of remotely sensed data and information in Burn Area Emergency Response (BAER) wildfire assessment

We used a value of information approach to demonstrate the cost-effectiveness of using satellite imagery as part of the Burn Area Emergency Response (BAER), a US federal program that identifies imminent post-wildfire threats to human life and safety, property and critical natural or cultural resources. We compared the costs associated with producing a Burn Area Reflectance Classification map and implementing a BAER when imagery from satellites (either Landsat or a commercial satellite) was available to when the response team relied on information collected solely by aerial reconnaissance. The case study included two evaluations with and without Burn Area Reflectance Classification products: (a) savings of up to US$51000 for the Elk Complex wildfire incident request and (b) savings of a multi-incident map production program. Landsat is the most cost-effective way to input burn severity information into the BAER program, with savings of up to US$35 million over a 5-year period.

Wildfire and COVID-19 pandemic: effect of environmental pollution PM-2.5 and carbon monoxide on the dynamics of daily cases and deaths due to SARS-COV-2 infection in San-Francisco USA.

The wildfire allied environmental pollution is highly toxic and can cause significant wide-ranging damage to the regional environment, weather conditions, and it can facilitate the transmission of microorganisms and diseases. The present study aims to investigate the effect of wildfire allied pollutants, particulate matter (PM-2.5 μm), and carbon monoxide (CO) on the dynamics of daily cases and deaths due to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in San Francisco, USA. For this study, we selected San Francisco, one of the regions affected by the wildfires allied pollution in California, USA. The data on the COVID-19 pandemic in San Francisco, including daily new cases and new deaths were recorded from Worldometer Web. The daily environmental pollutants particulate matter (PM-2.5 μm) and carbon monoxide (CO) were recorded from the metrological web "BAAQMD". The daily cases, deaths, particulate matter (PM-2.5 μm) and carbon monoxide were documented from the date of the occurrence of the first case of (SARS-CoV-2) in San Francisco, CA, USA, from March 20, 2020 to Sept 16, 2020. The results revealed a significant positive correlation between the environmental pollutants particulate matter (PM2.5 μm) and the number of daily cases (r=0.203, p=0.007), cumulative cases (r=0.567, p<0.001) and cumulative deaths (r=0.562, p<0.001); whereas the PM2.5 μm and daily deaths had no relationship (r=-0.015, p=0.842). In addition, CO was also positively correlated with cumulative cases (r=0.423, p<0.001) and cumulative deaths (r=0.315, p<0.001), however, CO had no correlation with the number of daily cases (r=0.134, p=0.075) and daily deaths (r=0.030, p=0.693). In San Francisco, one micrometer (μg/m3) increase in PM2.5 caused an increase in the daily cases, cumulative cases and cumulative deaths of SARS-COV-2 by 0.5%, 0.9% and 0.6%, respectively. Moreover, with a 1 part per million(ppm) increase in carbon monoxide level, the daily number of cases, cumulative cases and cumulative deaths increased by 5%, 9.3% and 5.3%, respectively. On the other hand, CO and daily deaths had no significant relationship. The wildfire allied pollutants, particulate matter PM-2.5μm and CO have a positive association with an increased number of SARS-COV-2 daily cases, cumulative cases and cumulative deaths in San Francisco. The metrological, disaster management and health officials must implement the necessary policies and assist in planning to minimize the wildfire incidences, environmental pollution and COVID-19 pandemic both at regional and international levels.

Characterizing fire effects on conifers at tree level from airborne laser scanning and high-resolution, multispectral satellite data

Post-fire assessment is made after a wildfire incident to provide details about damage level and its distribution over burned areas. Such assessments inform restoration plans and future monitoring of ecosystem recovery. Due to the high cost and time to conduct fieldwork, remote sensing is an appealing alternative to assess post-fire condition over larger areas than can be surveyed practically in the field. The aim of this study is to use remote sensing data to characterize post-fire severity at tree level in a mixed conifer forest following the Cascade and East Zone megafires of 2007 in central Idaho, USA. We used remote sensing metrics derived from Airborne Laser Scanning (ALS) data (2008) and high-resolution QuickBird (QB) multispectral satellite imagery (2007–2009) for calibrating and validating predictive models with field data (2008). We compared fire effects on trees in open canopies within recent fuel treatments to similar trees in closed canopies on adjacent, untreated sites. We observed more trees with charred crowns in high fire severity sites, mostly untreated, whereas we observed more trees with live crowns in low fire severity sites, independent of the treatment. Individual trees were more accurately detected from ALS data in treated sites with open canopies than untreated sites with closed canopies. For detected trees, the response variables predicted from ALS and QB metrics were total height (Ht), crown base height (CBH), total basal area (BAT), live basal area (BAL), scorched basal area (BAS), charred basal area (BAC) and crown severity (CS). None of the selected QB metrics were strongly correlated with the selected ALS metrics, which justified combining both data types into the predictive models. Random Forest regression models combining ALS + QB metrics or using ALS metrics alone performed similarly but clearly better than models using only QB metrics. This study shows the superiority of ALS data to high resolution, multispectral QB imagery for mapping fire severity at tree level. Managers with limited resources to plan for restoration of fire affected forests are advised to prioritize spending for data collection on ALS data and a modest number of field inventory plots, rather than QB or other broadband satellite imagery.

Semantic Interoperability for IoT Platforms in Support of Decision Making: An Experiment on Early Wildfire Detection.

One of the main obstacles towards the promotion of IoT adoption and innovation is data interoperability. Facilitating cross-domain interoperability is expected to be the core element for the realisation of the next generation of the IoT computing paradigm that is already taking shape under the name of Internet of Everything (IoE). In this article, an analysis of the current status on IoT semantic interoperability is presented that leads to the identification of a set of generic requirements that act as fundamental design principles for the specification of interoperability enabling solutions. In addition, an extension of NGSIv2 data model and API (de-facto) standards is proposed aiming to bridge the gap among IoT and social media and hence to integrate user communities with cyber-physical systems. These specifications have been utilised for the implementation of the IoT2Edge interoperability enabling mechanism which is evaluated within the context of a catastrophic wildfire incident that took place in Greece on July 2018. Weather data, social media activity, video recordings from the fire, sensor measurements and satellite data, linked to the location and the time of this fire incident have been collected, modeled in a uniform manner and fed to an early fire detection decision support system. The findings of the experiment certify that achieving minimum data interoperability with light-weight, plug-n-play mechanisms can be realised with significant benefits for our society.

Does Wildfire Open a Policy Window? Local Government and Community Adaptation After Fire in the United States.

Becoming a fire adapted community that can coexist with wildfire is envisioned as a continuous, iterative process of adaptation, but it is unclear how communities may pursue adaptation. Experience with wildfire and other natural hazards suggests that disasters may open a "window of opportunity" leading to local government policy changes. We examined how destructive wildfire affected progress toward becoming fire adapted in eight locations in the United States. We found that community-level adaptation following destructive fires is most common where destructive wildfire is novel and there is already government capacity and investment in wildfire regulation and land use planning. External funding, staff capacity, and the presence of issue champions combined to bring about change after wildfire. Locations with long histories of destructive wildfire, extensive previous investment in formal wildfire regulation and mitigation, or little government and community capacity to manage wildfire saw fewer changes. Across diverse settings, communities consistently used the most common tools and actions for wildfire mitigation and planning. Nearly all sites reported changes in wildfire suppression, emergency response, and hazard planning documents. Expansion in voluntary education and outreach programs to increase defensible space was also common, occurring in half of our sites, but land use planning and regulations remained largely unchanged. Adaptation at the community and local governmental level therefore may not axiomatically follow from each wildfire incident, nor easily incorporate formal approaches to minimizing land use and development in hazardous environments, but in many sites wildfire was a focusing event that inspired reflection and adaptation.

The Cooney Ridge Fire Experiment: An Early Operation to Relate Pre-, Active, and Post-Fire Field and Remotely Sensed Measurements

The Cooney Ridge Fire Experiment conducted by fire scientists in 2003 was a burnout operation supported by a fire suppression crew on the active Cooney Ridge wildfire incident. The fire experiment included measurements of pre-fire fuels, active fire behavior, and immediate post-fire effects. Heat flux measurements collected at multiple scales with multiple ground and remote sensors illustrate the spatial and temporal complexity of the fire progression in relation to fuels and fire effects. We demonstrate how calculating cumulative heat release can provide a physically based estimate of fuel consumption that is indicative of fire effects. A map of cumulative heat release complements estimates of ground cover constituents derived from post-fire hyperspectral imagery for mapping immediate post-fire ground cover measures of litter and mineral soil. We also present one-year and 10-year post-fire measurements of overstory, understory, and surface conditions in a longer-term assessment of site recovery. At the time, the Cooney Ridge Fire Experiment exposed several limitations of current state-of-science fire measurement methods, many of which persist in wildfire and prescribed fire studies to this day. This Case Report documents an important milestone in relating multiple spatiotemporal measurements of pre-fire, active fire, and post-fire phenomena both on the ground and remotely.

火烧对古尔班通古特沙漠土壤养分和土壤酶活性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 火烧对古尔班通古特沙漠土壤养分和土壤酶活性的影响 DOI: 10.5846/stxb201708111441 作者: 作者单位: 新疆乌鲁木齐新市区北京南路新疆生态与地理研究所,中国科学院新疆生态与地理研究所干旱区生物地理与生物资源与重点实验室,中国科学院新疆生态与地理研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 新疆维吾尔自治区青年科技创新人才培养项目（2014731022）；国家自然科学基金-新疆联合基金（U1503101） Effect of fire on soil nutrient content and enzyme activity in Gurbantunggut desert Author: Affiliation: Xinjiang Institute of Ecology and Geography， Chinese Academy of Sciences,Key liboratory of Biogeography and Bioresource in arid land，Xinjiang institute of Ecology and Geography，Chinese Academy of sciences,zhang yuanming Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以古尔班通古特沙漠2016年6月意外火烧事件为背景，对比分析火烧和未火烧样地区不同土壤深度化学性质、土壤酶活性的变化特征，为全面评估火烧对温带荒漠生态系统的影响提供土壤学依据。结果表明：火烧样地和对照样地土壤养分含量和酶活性总体上均表现为上层土壤（0-5 cm）大于下层土壤（5-10 cm），仅土壤氧化酶（过氧化氢酶）活性表现为下层土壤大于上层土壤。同时，火烧和土壤深度存在交互效应，火烧对土壤特性的影响受土壤深度的限制。土壤化学性质受火烧的影响主要表现在0-5 cm土壤层，尤其是速效养分在火烧之后有显著增加趋势。火烧对5-10 cm土壤层土壤化学性质无显著影响。火烧后，硝态氮（NO3-N）含量显著下降，铵态氮（NH4-N）含量上升。土壤水解酶、氧化酶活性在火烧之后降低，具体表现为，蔗糖酶、脲酶、β-葡萄糖苷酶活性在0-5 cm和5-10 cm土壤层均极显著下降，而碱性磷酸酶活性仅在0-5 cm土壤层显著下降。过氧化氢酶活性则在5-10 cm土壤层活性显著下降。表明上层土壤水解酶活性对火烧干扰较为敏感，氧化酶活性在火烧干扰下相对稳定。从各土层土壤酶活性的变化特征来看，火烧对水解酶活性的影响随土壤深度增加而降低，而氧化酶则呈现相反的趋势。总体而言，火烧显著提高了古尔班通古特沙漠土壤速效养分的含量，降低了土壤酶活性，不同土壤酶对火烧响应的敏感程度不同。为深入评估火烧干扰对温带荒漠生态系统的影响提供一定理论依据。 Abstract:Fire disturbance influences both above-ground and below-ground nutrient cycles by burning some of the vegetation, litter, and duff, which leads to nutrient losses. It can also cause important changes in soil chemical properties and enzyme activity. In desert ecosystems, large-scale fires, previously considered as rare events, are now a major threat to these areas. The present study was undertaken in Gurbantunggut desert, where wildfire incident occurred in July 2016, to examined the short-term effects of fire on soil nutrient content and enzyme activity in different soil layers (0-5 cm and 5-10 cm). The original vertical distribution patterns of soil nutrients and enzyme activity were not changed by fire disturbance. Soil nutrient content and soil enzyme activity, except for that of catalase, were higher in the 0-5 cm soil layer than in the 5-10 cm soil layer. An interaction was present between fire and soil depth, and the effect of fire on soil properties was limited by soil depth. Soil chemical properties were mainly affected by fire in the 0-5 cm soil layer. Soil hydrolase and oxidase activity decreased after the fire, and the activity of sucrase, urease and beta glucosidase decreased in the 0-5 and 5-10 cm layers. Alkaline phosphatase activity decreased only in the 0-5 cm soil layer,and catalase activity decreased only in the 5-10 cm layer. The activity of hydrolase in the upper soil layer was sensitive to fire disturbance, and that of oxidase was relatively stable under the interference of fire. Analysis of the characteristics of soil enzyme activity in the different soil layers indicated that effect of fire on hydrolytic enzyme activity decreased with increase in soil depth, while that of oxidase showed the opposite trend. Overall, fire disturbance increased the content of soil available nutrients and significantly decreased soil enzyme activity in Gurbantunggut desert. 参考文献 相似文献 引证文献