Division of forest fuel type areas of Heilongjiang Province by using GIS

Eight factors, including forest coverage, fuel load, species composition, elevation, monthly mean temperature, monthly mean relative humidity, monthly mean wind velocity, and monthly mean precipitation of fire season, were considered and the methods of weight, the cumulative probability, ARC/INFO technique, and raster-to-vector conversion were adopted in division of forest fuel type area. Firstly, the electronic maps of forest distribution and administrative divisions were built, then overlaid and transformed to the real-world coordinates. Finally, the forest fuel type areas of Heilongjiang Province including 81 counties were divided into five grades, accounting for 16%, 17%, 17%, 11%, and 38% respectively. The grade Ⅰ fuel type areas with highest fire danger rating mainly distributed on Daxinganling Mountains, Xiaoxinganling Mountains, and Zhangguangcailing Mountains, the grade Ⅴ fuel type areas mainly centralized on Songnen Plain, Sanjiang Plain, and other Plains, and other forest fuel type areas (grades Ⅱ, Ⅲ, and Ⅳ) were situated between plains and mountainous areas.

Supercritical extracts of forest fuels in Great Xing＇an Mountains

Extracts are important components of fuels. Fatty-extracts with high heating value （HV） are hypothe- sized by researchers as positively related to the HV of fuels. The Soxhlet extractor is typically used to extract fatty-extracts but it has shortcomings, including long processing time （8-10 h） and the requirement for large amounts of organic solvent. Supercritical extraction is an alternate and useful technique for extraction of natural products. However, published studies rarely discuss the relationship between extracts and HV. In this study, we assessed the supercritical extracts （SUE） of forest fuels in the Great Xing＇an Mountains. Our results indicated that the optimum conditions for extraction of SuEs were 40-60 mesh, 40-50 MPa, 45℃, 80 min and a CO2 flow rate of 1.5-2.0 dm3/min. The Soxhlet extracts contents and the SuE contents were all related to HV. However, R2 of the coniferous samples （0.8499） and needle samples （0.9722） demonstrated that the correlation between HV and the SuE content was closer. We conclude that supercritical fatty-extracts provide a useful index of the HV of fuels, especially coniferous fuels. SuE data can be used in fire management, for example to estimate the rate of fire spread or fire intensity.

DYNAMIC PREDICION OF FOREST FUEL LOADS BY GREY VERHULST MODEL

The variation of fuel loads after a fire for three forest types, phododendron -Larix gmetinii forest, herb--Larix gmelinii forest and herb--Betula plalyphlla forest , in the northern forest area of Daxing’anling region was discussed. The dynamic models were developed by gray theory for estimating the fuels loads of arbor- shrub, herbs’ grass, litter, and semi-decomposed litter, inflamma ble fuel and the total fuels in each forest type. After a fire, the inflammabIe fuel loads in phododendron-- Larix gmelinii forest and in the herb- - Betula platyphlla fores was estimated at 10.958 t/hm2and 10.473 t/hm2 respectively’ by 13 years later. and that was 12.297 t/hm 2 in herb--Larix gmeliniiforest by 7 years later.. It was predicated that a big fire may occur after 10 years based on inflammable fuel biomass accumulated.

DYNAMIC MODELS OF MOISTURE CONTENT OF FOREST FUELS

The fuel moisture content is an integral part of any workable fire danger-rating system. This paper presented dynamic models for estimating 1-h, 10-h. 100-h and 1000-h timelag fuels, that were developed by multiple regression and stepwise variable selection of statistics. The variables include both meteorological factors and moisture contents observed prior to the day correspondingly. The analysis revealed that the fuel moisture content are correlated positively with the precipitation of 24 hours prior to the observation time, and negatiyely with air temperature at observing height of 1.5 meter in forest.

Diurnal variation models for fine fuel moisture content in boreal forests in China

Studying diurnal variation in the moisture content of fine forest fuel(FFMC)is key to understanding forest fire prevention.This study established models for predicting the diurnal mean,maximum,and minimum FFMC in a boreal forest in China using the relationship between FFMC and meteorological variables.A spline interpolation function is proposed for describing diurnal variations in FFMC.After 1 day with a 1 h field measurement data testing,the results indicate that the accuracy of the sunny slope model was 100%and 84%when the absolute error was<3%and<10%,respectively,whereas the accuracy of the shady slope model was 72%and 76%when the absolute error was<3%and<10%,respectively.The results show that sunny slope and shady slope models can predict and describe diurnal variations in fine fuel moisture content,and provide a basis for forest fire danger prediction in boreal forest ecosystems in China.

A Geographical-Origin-Destination Model for Calculating the Cost of Multimodal Forest-Fuel Transportation

As a consequence of increasing demand for wood fuels, the management of forest-fuel production chains has become an important logistics issue in FinlandandSweden. Truck-based transportation has been the dominant method in fuel supply from the areas around power plants. However, increasing demand has led to enlargement of supply areas and greater variety in supply methods, including also railway and waterway transportation. This study presents a GIS-based calculation model suitable for cost calculations for power plants’ forest-fuel supply chains. The model has multimodal properties—i.e., it provides transfer of forest-fuel loads between transportation modes—and enables case-specific adjustment of transportation and material-handling cost parameters. The functionality of the model is examined with a case study focusing on a region of intense forest-fuel use. The results indicate that truck transportation is competitive with railway transportation also for long transport distances. However, increasing the proportion of multimodal transportation for other than economic reasons (e.g., for supply security) could be reasonable, since the impact on total supply costs is marginal. In addition to honing of the parameters related to biomass availability and transport costs, the model should be developed through inclusion of other means of transportation, such as roundwood carriers.

Southeast Tibet Forest Fuel Types and Flammability

Southeast Tibet forest is in east subtropical zone. This region natural environment is unique, influenced by the southwest monsoon, so forest fires are very easy to occur in the dry season. Forest in this region is over mature forest, and accounts for much proportion. Fire season in this area is winter and spring. But in the special year, forest fires can also occur in the hot summer. Fire season lasts from October to next February,but to April in an individual arid year. Most of the fires in this area are surface fires, crown fire, can occur after long time drought. Ground fires do not occur in the region.

THE ESTIMATE OF THE EFFECTIVE FUEL COMBUSTION VALUE OF FOREST COMMUNITY IN THE DAXINGAN MOUNTAIN

Under the condition of absolute dry, more than thirty forest fuel pararneters,ash content. extract and burning point were measured. By the method of regression step by step. we found an experience formula which can estimate effective fuel high combusti on value of forest community from the Daxingan Mountain,and then,By means of modifying moisture content. we gave an approximate formula about actual heat releasing of forest fuels in the forest fire behavior.

小兴安岭12种灌木的燃烧性研究

为比较黑龙江省小兴安岭12种典型灌木树种燃烧性差异,对生物防火树种筛选和配置提供参考,以黑龙江省小兴安岭地区12种灌木植物为主要研究对象,分别测定其干、枝、叶燃烧性指标,采用层次分析法(AHP)构建灌木植物燃烧性层次结构模型,确定燃烧性各指标权重,计算灌木不同器官燃烧性数值,结合专家打分法确定灌木各器官权重占比,得出12种灌木燃烧性排序。研究结果表明,整株的燃烧性最强的为刺玫果,最弱的为忍冬;干最易引燃的为接骨木,最难引燃的为忍冬;枝最易引燃的为接骨木,最难引燃的为忍冬;叶最易引燃的为刺五加,最难引燃的为红柳。研究结果可为小兴安岭地区灌木树种燃烧性研究提供理论依据,为林火预测预报、林火行为预报、可燃物管理等研究和应用提供有效的支持。

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.

Wildland fires and moist deciduous forests of Chhattisgarh, India: divergent component assessment

We studied moist deciduous forests of Chhattisgarh, India （1） to assess the effect of four levels of historic wildland fire frequency （high, medium, low, and no-fire） on regeneration of seedlings in fire affected areas during pre and post-fire seasons, （2） to evaluate vegetation struc- ture and diversity by layer in the four fire frequency zones, （3） to evalu- ate the impact of fire frequency on the structure of economically impor- tant tree species of the region, and （4） to quantify fuel loads by fire fre- quency level. We classified fire-affected areas into high, medium, low, and no-fire frequency classes based on government records. Tree species were unevenly distributed across fire frequency categories. Shrub density was maximum in zones of high fire frequency and minimum in low- frequency and no-fire zones. Lower tree density after fires indicated that regeneration of seedlings was reduced by fire. The population structure in the high-frequency zone was comprised of seedlings of size class （A） and saplings of size class （B）, represented by Diospyros melanoxylon, Dalbergia sissoo, Shorea robusta and Tectona grandis. Younger and older trees were more abundant for Tectona grandis and Dalbargia sis- soo after fire, whereas intermediate-aged trees were more abundant pre- fire, indicating that the latter age-class was thinned by the catastrophic effect of fire. The major contributing components of fuel load included duff litter and small woody branches and twigs on the forest floor. Total fuel load on the forest floor ranged from 2.2 to 3.38 Mg/ha. The netchange in fuel load was positive in high- and medium-frequency fire zones and negative under low- and no-fire zones. Repeated fires, how- ever, slowly reduced stand stability. An ecological approach is needed for fire management to restore the no-fire spatial and temporal structure of moist deciduous forests, their species composition and fuel loads. The management approach should incorporate participatory forest manage- ment. Use of controlled fire, fire lines and mapping of fire prone areas are fundamental principles of fire hazard reduction in these areas.

Forest utilization patterns and socio-economic status of the Van Gujjar tribe in sub-Himalayan tracts of Uttarakhand,India

The present study was conducted on the Van Gujjar tribe inhabiting a sub-Himalayan tract in the North Western Himalayas of Uttarakhand State, India. The Van Gujjars have been practicing transmigration over hundreds of years. They migrate each year with their households and livestock between summer and winter pastures. A few years ago with the announcement of the establish- ment of the Rajaji National Park, the tribe has been forced out of the forest area and rehabilitated outside the park, which has affected their lifestyle. The newly established rehabilitation colony in the Gandikhata area of Haridwar District of Uttarakhand State was taken as a case study. The aims of the present study were to understand and evaluate the socio-economic status of the Van Gujjars in their newly established rehabilitation colony, the utilization pattern of forest resources by the tribe and their relative preference for selec- tive trees for various uses. A total of 176 households were interviewed （giving equal weight to all economic classes and family every size） by using pre-structured questionnaires. The education level was very low （12.9%） and the average income per household was recorded as Rs. 36000 （approximately $ 803） per year. The major source of income was dairy production （80.6%） followed by labor employment （13.9%）, NTFPs （4.2%） and agricultural production （1.4%）. More than 90% of fuel wood and fodder is extracted from the forest. The average fuel wood and fodder consumptions per household per day were recorded as 25.86 and 21.58 kg, respectively. A total of 35 species of cultivated plants and 89 species of wild plants were found to be utilized as food sources. Selectively 25 wild tree species are well known as being used by the Van Gujjars as fodder, fuel wood, agricultural implements, household articles, dye, medicine, fiber and other products. According to their utility value, the most preferred and useful tree species is Ougeinia oojeinensis, followed by Terminalia alata, Bombax ceiba, Shorea robusta and Dalbergia sissoo,

Analysis of Forest Waste Management and Recycling Potential in Nigeria

Forest wastes are renewable resources that can serve as sources of energy for heat and electricity generation. How these materials are managed in order to reduce their contribution to the release of greenhouse gases, reduce subsequent climate change challenges and their potential use in bio-energy production has remained a myth in Nigeria. In this paper, extensive review of the literature was carried out to arrive at the findings. More than 93% of all wood processing industries in Nigeria are sawmills. In addition to sawmills there are the plywood mills, furniture processing industries, and particleboard mills. Sawdust is the major waste generated from wood processing in the various processing units. Currently, the most popular waste management practice in Nigeria is burning. Dumping in open spaces, riverbanks, and water bodies is also obtainable. There is no record of wood waste recycling for bio-fuel production at the moment. Wood wastes are reused for agricultural production (mulching, manure) and as firewood. These actions contribute to the release of greenhouse gases and subsequently contribute to global warming. There are policies and agencies put in place to address this menace but implementation is a problem. An increase in proper waste management education and awareness, and aid from developed countries in terms of providing the technology needed for recycling and incineration, will go a long way in ensuring the safety (from climate change and consequences) of the local people, the environment, and the world at large.

Estimation of gases emitted by forest fires based on remote sensing data

Forest fire, an important agent for change in many forest ecosystems, plays an important role in atmo- spheric chemical cycles and the carbon cycle. The primary emissions from forest fire, CO2, CO, CH4, long-chained hydrocarbons and volatile organic oxides, however, have not been well quantified. Quantifying the carbonaceous gas emissions of forest fires is a critical part to better under- stand the significance of forest fire in calculating carbon balance and forecasting climate change. This study uses images from Enhanced Thematic Mapper Plus （ETM＋） on the Earth-observing satellite LANDSAT-7 for the year 2005 to estimate the total gases emitted by the 2006 Kanduhe forest fire in the Daxing＇an Mountains. Our results suggest that the fire emitted approximately 149,187.66 t CO2, 21,187.70 t CO, 1925.41 t CxHy, 470.76 t NO and 658.77 t SO2. In addition, the gases emitted from larch forests were significantly higher than from both broadleaf-needle leaf mixed forests and broadleaf mixed forests.

Rapid Increase in Log Populations in Drought-Stressed Mixed-Conifer and Ponderosa Pine Forests in Northern Arizona

Down logs provide important ecosystem services in forests and affect surface fuel loads and fire behavior. Amounts and kinds of logs are influenced by factors such as forest type, disturbance regime, forest management, and climate. To quantify potential short-term changes in log populations during a recent global- climate-change type drought, we sampled logs in mixed-conifer and ponderosa pine (Pinus ponderosa) forests in northern Arizona in 2004 and 2009 (n = 53 and 60 1-ha plots in mixed-conifer and ponderosa pine forests, respectively). Over this short time interval, density of logs, log volume, area covered by logs, and total length of logs increased significantly in both forest types. Increases in all log parameters were greater in mixed-conifer than in ponderosa pine forest, and spatial variability was pronounced in both forest types. These results document rapid increases in log populations in mixed-conifer forest, with smaller changes observed in ponderosa pine forest. These increases were driven by climate-mediated tree mortality which created a pulse in log input, rather than by active forest management. The observed increases will affect wildlife habitat, surface fuel loads, and other ecosystem processes. These changes are likely to continue if climate change results in increased warmth and aridity as predicted, and may require shifts in management emphasis.

基于可燃物特征的塞罕坝林场人工林小班森林火险区划

【目的】以塞罕坝机械林场为例,建立一种基于可燃物特征的森林火险区划方法,为林场尺度火险区划提供借鉴。【方法】选取15个火险影响因子,运用层次分析法(AHP)、专家打分法和判断矩阵法获得小班尺度引燃危险、火强度危险和综合火险的因子权重,以小班调查数据和可燃物理化性质测定数据为基础,计算每个小班的引燃危险指数、火强度危险指数和综合火险指数;采用聚类分析法和ArcGIS技术,得到林场内引燃危险、火强度危险和综合火险的等级区划图,分析林场区域的火灾发生危险性。【结果】1)在塞罕坝机械林场,引燃危险等级极高(Ⅴ_(Y))区域面积占林场总面积的9.21%,主要零散分布于林场西部、南部和中部;高(Ⅳ_(Y))和较高等级(Ⅲ_(Y))分布区域较广,全区均有分布,较高以上等级(Ⅲ_(Y)、Ⅳ_(Y)、Ⅴ_(Y))面积占比67.95%。2)火强度危险极高等级(Ⅴ_(Q))面积最大,占林场总面积的46.42%,其次是高等级(Ⅳ_(Q)),面积占比26.38%,二者面积之和占比72.8%,集中在林场南部和西部;较高等级(Ⅲ_(Q))面积占比7.95%,主要分布在东部。3)综合火险等级高(Ⅳ_(Z))和较高(Ⅲ_(Z))面积占比大,分别为29.07%和28.12%;极高等级(Ⅴ_(Z))面积占比也达19.13%;较高以上等级(Ⅲ_(Z)、Ⅳ_(Z)、Ⅴ_(Z))区域面积总占比为76.32%,主要分布于林场西部、南部和中部。【结论】基于层次分析法、聚类分析法和ArcGIS技术的火险区划方法,能在小班尺度很好地进行森林火险分类,得到引燃危险、火强度危险和综合火险区划,对林场等级的可燃物管理有参考价值。塞罕坝机械林场综合火险等级很高,特别是西部、南部和中部;林场火强度危险等级极高(Ⅴ_(Q))和高(Ⅳ_(Q))的区域面积很大,一旦着火极易引发高强度森林火灾。引燃危险等级高和火强度危险等级高的区域并不完全重合,需在引燃危险等级高的区域内加强火源管理和易燃可燃物管理,降低火发生概率,建议在火强度危险等级高的区域和引燃危险等级高的区域之间规划隔离带,以有效阻滞可能发生的林火向火强度危险等级高的区域快速蔓延,防控大火巨灾发生。

云南省果林修剪枝条资源评估及生物质能潜力分析

以2010—2020年果林修剪枝条及45个水果种植(柑橘、石榴、苹果、梨和葡萄)主要优势县(市、区)为研究对象,利用果林修剪系数及折标煤系数,测算云南省果林修剪资源量,估算生物质燃料潜力,解析其时空分布特征。结果表明:2010—2020年云南省果林修剪枝条资源总量呈上升趋势,枝条年均修剪用量为152.27万t,不同区域之间果林修剪枝条资源量差异明显;2020年云南省果林修剪枝条资源量为261.75万t,其中超10万t的县(市、区)6个,5万~10万t的县(市、区)份有8个,低于5万t的有31个;将枝条制成颗粒燃料折算成标准煤,年均量为91.80万t,标准煤折算成天然气和发电量,年均量分别为69.03亿m^(3)和74.72亿kW·h,其产生的年均潜在价值为41.84亿元。云南省果林修剪枝条能源化潜力巨大,发展生物质燃料的资源禀赋条件优异,具备产业化发展生物质颗粒燃料的资源基础。

基于Sentinel数据的沅陵县针叶林可燃物载量估测研究

森林可燃物是引发森林火灾的重要因素之一,准确估测森林可燃物载量对于制定火灾防控策略、提高火灾预警能力以及保护生态环境具有重要意义。以湖南省沅陵县Senitnel-1A和Sentinel-2A影像为数据源,通过提取多源数据的不同类型遥感因子,结合地面调查获取的样地可燃物载量信息,采用前向特征筛选法和4种机器学习模型[多元线性回归(multiple linear regression,MLR)、k最近邻(k-nearest neighbor,kNN)、支持向量机回归(support vector regression,SVR)、随机森林(random forest,RF)]构建了针叶林可燃物载量反演模型,并对研究区内针叶林可燃物载量进行反演。结果表明:①基于Sentinel-1A数据提取的VH极化后向散射系数与针叶林可燃物载量有较高的相关性;②相比于单一数据源,联合Sentinel-1A和Sentinel-2A数据可显著提高针叶林可燃物载量估测精度,最优模型R^(2)分别提高了0.19、0.29,rRMSE分别降低4.66、6.94个百分点,RMSE分别降低了6.13、9.13 t/hm^(2),平均rRMSE分别降低了5.17、5.75个百分点,最优模型为SVR模型,其R^(2)=0.5,rRMSE=27.71,RMSE=36.47 t/hm^(2)。Sentinel-1A数据的加入有利于针叶林可燃物载量估测精度的提升。

若尔盖县主要林分可燃物载量特征及林火防控分析

按照《全国森林和草原火灾风险普查四川省试点调查技术指南》,分气候区、森林起源、龄组、郁闭度、优势树种对森林可燃物调查类型进行调查,分析确定火灾风险。根据林分型分层结果、面积比例和标准地数量要求,确定各类型布设调查标准地数量,再把各类型标准地分别布设在森林植被分布图上。按标准设置正方形标准地,开展乔木、灌木、草本、枯落物、腐殖质等可燃物载量调查。结果表明:各层次可燃物载量如下,乔木层153.04~302.28 t/hm^(2);灌木层8.30~19.03 t/hm^(2);草本层0.69~2.32 t/hm^(2);枯落物层3.33~4.74 t/hm^(2);腐殖层2.47~4.72 t/hm^(2);根据总可燃物载量比较,相同林分型中,随着林龄的增加,可燃物载量整体呈现上升趋势。云杉、桦木的成过熟林总可燃物载量比近熟林有所下降,这可能与当地人为砍伐等破坏有关;林分中最易引起火灾的可燃物为地表可燃物和草本植物。4种林分型下,平均死可燃物载量为5.66~9.18 t/hm^(2),发生较大火灾的可能性较小。但近熟林和成过熟林中的死可燃物载量较大,应重点关注。森林火灾引发的影响因子较多,应根据林分可燃物特征、立地条件、人文情况等实际情况,提出符合防火实情的防火区划和防火减灾策略。

川西南地区云南松飞播林火灾研究

云南松是我国重要的造林绿化树种,也是西南地区飞播造林的主要树种之一,为国土绿化、森林覆盖率提高等发挥了重要作用。通过文献综述,分析云南松飞播林火灾危险性及特征,火灾形成条件和影响等。结果表明:现有云南松飞播林大部分是近熟林和成熟林,管护较好,林下可燃物载量大、连续性好,火源较多,火灾形成机制很复杂,火灾危险性高。要系统谋划飞播林的林下经济发展,生态优先,因地制宜,充分利用好林地资源,拓展林间、林下发展空间,将生态效益转化为经济效益。研究结果能更好总结现行云南松飞播林火管理政策和方法,提出与时俱进的飞播林火灾防控措施,为积极预防和安全扑救提供理论参考。