芷江县森林火灾与气象条件的关系及其防护对策

在系统分析林火与气象条件关系的基础上，给出不同高度的预测通式，进一步完善了林火“综合指标”预报法。并从实际应用出发，总结归纳可燃物特征与含水率的关系。     

铁峰山林区林火阻隔网建设探讨

林火阻隔网,就是人为地将集中连片的森林机械地切割成相对隔离的若干林块,使河流、防火林道、生物防火林带、防火线相互联接,形成网络,阻隔森林火灾蔓延。一旦有火,可起到隔火作用,最大限度地将林火控制在最小范围内,把火灾损失降到最低程度。铁峰山林区位于重庆市万州区、开县、云阳县三交界的铁峰山脉,属渝东北生态涵养发展区,是三峡库区重要的生态屏障。由此,对该区域林火阻隔网建设提出建议,旨在加强该区域森林资源保护。     

基于空间Logistic的黑龙江省林火风险模型与火险区划

林火风险分析和森林火险区划是林火管理的重要组成部分。该文利用黑龙江省2000-2010年MODIS火烧迹地遥感数据集MCD45A1,在RS和GIS技术支持下构建林火空间分布与林火影响因子间的空间Logistic林火风险模型,在较大时间尺度和省域空间尺度上进行了森林火险区划研究,结果表明:通过空间采样构建的Logistic林火风险模型拟合效果很好,在显著性水平为0.05的情况下,通过模型系数的混合检验和Wald检验;相对运行特征(relative operating characteristic,ROC)值为0.753;经图层运算得到森林火险概率分布图,并将黑龙江省分为无火险区、低火险区、中火险区、高火险区和极高火险区。大兴安岭山地集中了极高火险区和高火险区;小兴安岭基本上属于高火险区和中火险区;东部山地小部分地区属于中火险区;其它地区属于低火险区和无火险区。黑龙江省森林火险的定量定位评价可为林火的预防、扑救以及防火指挥员进行防火规划和部署扑火力量、指导森林防火工作提供科学依据。     

干旱河谷区草坡防火工程对坡面径流侵蚀的影响

为探究干旱河谷区草坡防火工程对坡面径流侵蚀的影响，以四川省凉山州的3个27.5°的草地坡面为研究对象，进行流量分别为6,9,12 L/min的模拟冲刷试验。3个坡面的处理为：(1)移除植被地上地下部分，平整坡面代表草坡防火通道；(2)移除植被地上部分代表草坡防火隔离带；(3)未进行处理作为对照。通过收集坡面出口的产流量和产沙量，研究不同的防火工程在不同的放水冲刷流量下分别对坡面径流侵蚀的影响。结果表明：(1)草坡由于修建防火通道导致坡面土质松散，水分入渗量增加，初始产流时间表现为草坡防火通道(20.33 min)>对照坡面(7.62 min)>草坡防火隔离带(5.22 min);(2)3个流量下的累计产流量和累计产沙量均表现为草坡防火通道>草坡防火隔离带>对照坡面，并且随着放水流量的增加3个坡面之间的差异显著增加，表明草坡防火工程的修建加剧陡坡水蚀；(3)对照坡面的产流量和产沙量之间呈线性关系，而草坡防火通道坡面的产流量与产沙量之间的关系呈指数、对数或线性关系，草坡防火隔离带坡面的产流量和产沙量之间呈对数或线性关系，表明草坡防火工程的修建改变水沙之间原有的线性关...     

森林火险气象等级信息发布系统的开发

建立森林火险气象等级发布系统管理平台,以连续天况和后续天气预报为基础,结合雨量数据分析空气湿度、土壤湿度和森林覆盖情况制订森林火险气象等级预报。以采集预报因子,数据库整合分发信息为核心。从PC终端延伸拓展至智能手机、PDA的新一代技术,是基于移动互联网,让管理者、护林防火员利用显示屏、手机随时随地开展各类信息和资料查询活动,从而大量节约森林防火的管理成本和运营成本,组织防火灭火的效能得以大幅度提高。     

晋南常见阔叶落叶灌木的定量生态研究

在晋南霍山地区常见野生阔叶灌木及部分乔木树种植物生态调查的基础上，应用定量生态学理论，分析了它们的生态位宽度，生态位重叠两指标，并进行了适应性评价，从而筛选出适宜于该地区水保造林的9种先锋灌木树种以及灌木－灌木混交林，乔木－灌木混交林的适宜混交灌木树种，为当地植被建设提供了重要的理论指导。     

基于GIS的土壤管理信息系统的设计与实现——以贵州省为例

本文介绍了以贵州省为例的土壤管理信息系统的开发、建立和应用。系统利用Visual Basic6．0及Map Objects2．2为开发软件;以1999年贵州省1：25万行政区划图为系统底图,建立空间数据库;以1820组农业土壤样品、近1万多个重金属环境检测数据,建立属性数据库;按照国家土壤环境质量评价标准建立分析评价模型,获得贵州省农业土壤环境质量数据库。此外,文章还详细介绍了该系统的主要功能和应用。系统的开发应用,为进一步加强贵州省农业土壤的管理和环境质量研究,提供了基础平台和数据支持。     

林火管理与地信技术结合的具体实践

地理信息系统(Geographic Information System,简称为GIS)的基础通常为地理空间数据,是一种在计算机软件的保障下,对空间有关数据信息进行显示、分析、模拟、操作、管理与收集,同时向使用者提供精确的动态地理信息与空间地理信息的系统,其在林火管理中具有非常重要的作用,可有效提高林火管理效率,进而降低林火发生概率。基于此,主要对GIS在林火管理各方面的应用进行了探讨,在分析GIS相关内容的基础上,对应用GIS进行森林火险区划、林火预测预报和林火设施的布局进行了分析研究。     

松嫩平原水土保持价值的量化研究

近几十年来，松嫩平原的生态环境严重恶化，荒漠化迅速发展，这与区域水土保持功能持续下降有关。本文应用生态学、经济学和生态环境科学等学科的有关理论，以TM／MODIS／DEM数据为基础，应用3S技术建立了松嫩平原水土保持价值的复合计算模型。计算表明，全区2001年水土保持总价值为662．63亿元，就单位面积的水土保持价值而言．林地最高，为173．59万元／km^2，草地次之，为70．42万元／km^2，耕地很低，为24．53万元／km^2，难利用地仅为2．89万元／km^2。水土保持价值分布的总趋势从东北向西南递减，从193．86万元／km^2降至18．87万元／km^2。研究指出，进行林地、草地建设是提高区域水土保持功能的关键，中、西部尤应加强水土保持工作。本文不仅解决了水土保持价值的量化问题，而且为绿色GDP的核算提供了基础数据。     

朝阳市4种乡土树种叶面积回归方程的研究

以朝阳市4种常用的乡土绿化树种为调查研究对象,在朝阳市人民公园、凌河公园、凤凰山、北票、孙家湾等地针对每种树的不同规格进行实地测量,每个树种测量了25株树的胸径或冠幅、树高、叶片质量。利用Excel软件对每个树种的叶面积与胸径或冠幅、树高之间的相关关系进行回归拟合,建立一元、二元回归方程,得到了叶面积回归模型。根据绿地或一个地区园林植物的规格大小,应用回归方程便可很快计算出这一绿地或地区绿量的总和,从而使方程应用具有较强的可操作性,为园林绿化生态效益的定量研究提供了合理的基础手段。     

北京西山地区林火对土壤性质的影响

 为进行火烧迹地的管理,采用调查取样和室内分析方法,对北京西山地区不同林火强度下油松林土壤物理和化学性质的变化进行了研究。结果表明:与未火烧相比,中度火烧会显著提高土壤密度,显著降低土壤总孔隙度、土壤黏粒含量和田间持水量,而毛管孔隙和非毛管孔隙的变化却不明显;轻度火烧对土壤物理性质的影响不显著。轻度火烧会显著地提高0～5cm范围的土壤有机质含量,而中度火烧会显著降低土壤有机质和全氮含量。轻度火烧使土壤pH值增加,其中0～2cm的差异达到显著水平;另外,0～5 cm土层Ca²⁺和Mg²⁺的含量比中度火烧和未火烧土壤有明显的提高。因此,轻度火烧有利于改善土壤的性质。     

Throughfall,runoff and soil erosion after prescribed burning in gorse shrubland in Galicia (NW Spain)

The first‐year effect of two different prescribed burning treatments on throughfall, runoff and soil erosion was evaluated in gorse shrubland (Ulex europaeus L.) in Galicia (NW Spain). The treatments compared were: intense burn, light burn and control (no burn). Accumulated annual throughfall represented between the 81 and 87 per cent of total rainfall in intensely burned and lightly burned areas, respectively, whereas in the unburnt areas it was 60 per cent. No significant differences between burning treatments were found for the annual throughfall. However, runoff was significantly greater in intensely burned plots (1·5‐times) than in lightly burned plots. Burning also resulted in a significant increase in runoff (between 2·5 and 1·7‐times, respectively) compared with controls. Total soil losses were small in all treatments, but the intense burn caused significantly greater soil erosion (5·8‐times) compared with the unburned areas. Soil losses after the light burn did not significantly differ from the control although they were higher (2·3‐times). The relationships obtained between erosion and several rainfall parameters were significantly different in burned areas compared to the control. The same response was observed for runoff. Annual erosion losses showed a strong dependence on percentage of bare soil even for small values of this variable. Litter thickness was also a very important variable influencing on erosion rates. This study indicated that by combining ignition techniques and high litter moisture content to maintain the percentage of bare soil below 85 per cent, soil erosion was low. Nevertheless, this result was constrained by the low rainfall that occurred during the study. Copyright © 2005 John Wiley & Sons, Ltd.     

火烧对不同林型下森林土壤水分物理性质的影响

通过对大兴安岭松岭林区白桦林、落叶松林以及白桦落叶松混交林的当年高强度火烧迹地与对照样地的土壤水分物理性质进行测定和比较研究。结果表明:在火烧迹地和对照样地无论是土壤容重、土壤孔隙度、土壤持水量还是贮水能力,0~10 cm土层土壤都较10~20 cm土层土壤优越,火烧没有改变随深度变化的趋势,但相差明显增高。3种林型相比,在对照样地,白桦林土壤通气性优于落叶松林,而在火烧迹地,落叶松林优于白桦林。无论是在对照样地还是火烧迹地,落叶松林土壤的持水量平均值均大于白桦林,而白桦林土壤的平均贮水能力优于落叶松林。总体上看,在研究地区无论是土壤通气性、土壤持水量还是贮水能力,白桦林和落叶松林都较白桦落叶松混交林优越。火烧迹地与对照样地相比,火烧对3种林型的影响趋势相同,即土壤容重增加,土壤平均孔隙度以及土壤持水量减小。     

利用遥感监测亚像元分解遗传算法估算森林火灾面积

牛顿迭代法是林火亚像元分解的常用算法,但其火区面积计算精度取决于背景温度的估算精度,遗传算法具有全局寻优能力,本文尝试以火区面积百分比Af、火区温度Tf、背景温度Tbg为优化变量,采用RAGA遗传算法对林火亚像元辐射率平衡方程全局寻优求解。结果表明：用RAGA遗传算法比牛顿迭代法计算的结果更符合实际,迭代误差低2个数量级,用此方法对2005年四川省木里县三处森林火灾某时刻燃烧区面积进行估算,其结果对火情通报和火灾扑救工作具有重要的参考价值。     

Effects of fire and torrential rainfall on erosion in a Mediterranean gorse community

Wildland fires and torrential rainfall are important factors affecting Mediterranean nature and human society. In this paper, we investigate their combined impact on a fire‐prone vegetation community at the east coast of Spain. Our results show that shrub cover provides an effective control of erosion even under simulated extreme rainfall events. After fire, soil erosion increased noticeably; however, the amount of sediment produced varied greatly, which can be explained by variations in fire severity. The quantity of litter debris after the fire plays a decisive role in controlling the erosion that follows. Copyright © 2003 John Wiley & Sons, Ltd.     

Population viability analysis and fire return intervals for an endemic Florida scrub mint

We use population viability analysis of an endangered Florida scrub mint, Dicerandra frutescens, to specify the optimal fire return intervals for its long-term persistence and for its specific habitat. We derived 83 population projection matrices from 13 years of demographic data from eight populations, 59 matrices from scrub populations and 24 from firelane or yard edges. Seed dormancy and germination transitions were inferred based on experimental data and verified by comparing modeled vs. observed population trajectories. Finite rates of increase in scrub sites were highest shortly after fire and declined steeply through 10 years postfire. The break-even value of λ = 1 was passed quickly, in about six years, suggesting that populations >6 years postfire were already facing decline. The decline is probably related to the rapid growth of competing shrubs in the habitat of D. frutescens. In long-unburned sites, finite rates of increase were nearly always <1 and declined the most in the long-unburned site with no foot trails or treefall gaps. Finite rates of increase in firelane populations also declined with years since fire or last disking. The yard edge population showed λ values both >1 and <1, with no temporal trend. Stochastic simulations in scrub sites suggested an optimal regular fire return interval of about 6-12 years. Regular fires at this interval were more favorable than stochastic fire regimes, but stochasticity reduced extinction percentages at longer fire return intervals. Stochastic fire return intervals implied a wider optimal fire return interval of 6-21 years. We suggest that prescribed fire in Florida scrub on yellow sand has occurred (and needs to occur) more frequently than previously recommended.     

林火前后坡面覆盖类型对产流产沙影响的模拟试验

通过室内模拟降雨试验,设置3种降雨强度(30,60,90 mm/h)和3种地表覆盖类型(裸土坡面、1 cm马尾松枯落物覆盖、1 cm马尾松灰烬覆盖),研究林火发生前后不同地表覆盖下的坡面产流产沙过程,明确枯落物和植物灰烬覆盖的减流减沙效益。结果表明:(1)相比裸坡,枯落物和灰烬覆盖下的坡面初始产流时间分别延长33%~80%和51%~200%,灰烬覆盖对延缓产流的效果更为明显;(2)相比裸坡,枯落物覆盖的减流效果稳定在12%~36%,而灰烬覆盖在中小雨强的减流效果高于70%,在90 mm/h雨强时减流效果降低至7%;(3)裸土坡面产流呈现先快速升高后稳定的趋势,而枯落物和灰烬覆盖坡面产流效果呈现"阶梯"形上升趋势;(4)枯落物覆盖能够减小径流携沙量和总产沙量,在3种雨强下减沙效益均高于85%,且高于同雨强下灰烬覆盖的减沙效益。枯落物覆盖的减流减沙效果在不同雨强下表现较为稳定,而灰烬覆盖的减流减沙效果受降雨强度的影响显著,且枯落物覆盖的减沙效益在3种雨强下均优于灰烬覆盖,说明在林火发生后地表覆盖改变是引起土壤侵蚀增加的重要因素之一。     

Immediate effects of wildfires on water repellency and aggregate stability in Mediterranean calcareous soils

Alkaline soils are considered much less prone to developing water repellency induced by fire than acidic soils. Here we report on the persistence of water repellency present in calcareous soils immediately after wildfires in 10 burned areas in SE Spain, its distribution in different aggregate size fractions (< 2, 2–1, 1–0.5, 0.5–0.25 and < 0.25 mm) and on results from aggregate stability tests. We also distinguished between soil samples taken beneath pine (Pinus halepensis) and beneath understory vegetation.     

Charcoal mineralisation potential of microbial inocula from burned and unburned forest soil with and without substrate addition

Effects of fire on the functioning of the soil microbial community are largely unknown. In this study, we addressed the charcoal mineralisation potential of microbial inocula extracted from burned and unburned soil. The mineralisation of charcoal was analysed during a 1 month incubation experiment under controlled conditions with and without substrate addition. The aim of the study was to elucidate (1) the indirect effect of fire on the functioning of the soil microbial community in terms of charcoal degradation and (2) the possibility to stimulate this degradation by addition of two substrates of increasing complexity. Our conceptual approach included the monitoring of CO₂ emission from microcosms containing laboratory-made charcoal and microbial inocula from burned and unburned soil with and without ¹³C labelled glucose and cellulose.Our results showed higher charcoal mineralisation without substrate addition in microcosms with the inocula from unburned soil compared to burned soil. Charcoal mineralisation was stimulated by the addition of glucose, whereas cellulose addition did not induce a priming effect. We observed a higher stimulation of charcoal mineralisation induced by glucose for the inoculum from burned soil compared to the inoculum from unburned soil. We concluded that fire did affect the functioning of the soil microbial community in terms of charcoal degradation and that the important priming effect induced by glucose may be explained by an increase of the overall microbial activity, rather than selective stimulation of charcoal degrading microbial communities.