Fire-resistant tree species play a crucial role in forest fire prevention, utilizing several physiological and molecular mechanisms to respond to extreme heat stress. Many transcription factors (TFs) and genes are known to be involved in the regulatory network of heat stress response in plants. However, their roles in response to high temperatures induced by fire remain less understood. In this study, we investigated Schima superba, a fire-resistant tree, to elucidate these mechanisms. Leaves of S. superba seedlings were exposed to fire stimulation for 10 s, 30 s, and 1 min, followed by a 24-h recovery period. Fifteen transcriptomes were assembled to identify key molecular and biological pathways affected by high temperatures. Differentially expressed genes (DEGs) analysis revealed essential candidate genes and TFs involved in the heat stress response, including members of the ethylene-responsive factors, WRKY, MYB, bHLH, and Nin-like families. Genes related to heat shock proteins/factors, lipid metabolism, antioxidant enzymes, dehydration responses, and hormone signal transduction were differentially expressed after heat stress and recovery, underscoring their roles in cellular process and recovery after heat stress. This study advances our understanding of plant response and defense strategies against extreme abiotic stresses.

Heat stress due to external heat sources such as fire is an ecological problem for plants. When forest plants suffer from fire, high temperatures cause an array of morphological, physiological, and biochemical changes, which affect growth and development. Michelia macclurei Dandy is an evergreen broad-leaved tree species with the characteristics of fast growth, strong adaptability, and good fire-resistance. Some studies have improved the understanding of how fire behavior affects physiology, function and mortality, but the extreme heat response genes and mechanisms need improved understanding. In this study, we conducted a fire experiment (slight and severe) and RNA-Seq in M. macclure. The de novo assembly obtained 104,052 unigenes, and 48.46% were annotated in at least one public database. Specifically, 4458 and 4810 differentially expressed genes (DEGs) were identified in slight and severe fire treatment groups, respectively. In two treatment groups, 612 unigenes were differentially expressed, which were enriched in ‘oxidoreductase activity’ in the molecular function (MF) category of Gene Ontology (GO) enrichment analysis, suggesting the core role of oxidoreductase activity in response to extremely high temperatures in M. macclurei. In KEGG enrichment analysis of DEGs, the ‘plant hormone signal transduction’ is overrepresented, suggesting that this process plays an important role during heat response in M. macclurei. In the pathways of cytokinine and salicylic acid, some vital DEGs were enriched, which were related to cell division, shoot initiation, and disease resistance, and the potential interactions during heat stress were discussed. Moreover, the DEGs linked to heat stress response were identified, including heat shock factors, stress enhanced protein, signal transduction, photosystem, and major transcription factors. The qRT-PCR examination of various tissues, expression dynamics, and treatments revealed that the genes coding for the heat shock protein HSF30, stress enhanced protein, and photosystem I reaction center subunit II exhibited particularities in leaf tissue. Genes coding for heat shock proteins displayed a distinct expression pattern between fire treatment and conventional heat stress, which could signify the distinctive function of HSPs and the mechanism of heat responses. Altogether, these may interact to respond to fire stress through alterations in cellular processes, signaling transduction, and the synthesis and degradation of response proteins in M. macclurei. The results of this study provide a crucial transcriptional profile influenced by heat stress in M. macclurei, and could be of great use to explore the fire prevention mechanisms of fire-resistant tree species.

Michelia macclurei (Dandy, 1928) is an evergreen broad-leaved tree species native to South China. This species has great ecological and economic importance. However, the genomic study of M. macclurei has lagged far behind. Here, we reported the complete chloroplast genome sequence of M. macclurei. The chloroplast genome size of M. macclurei was 160,139 bp, consisting of a pair of inverted repeat (IR) regions (26,575 bp), which was separated by a large single copy (LSC) region (88,167 bp) and a small single copy (SSC) region (18,822 bp). A total of 113 unique genes were annotated, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. The overall GC content was 39.2%. Phylogenetic analysis based on 16 whole chloroplast genome sequences of Michelia species suggested that M. macclurei and M. maudiae are sister to each other, and jointly sister to M. chapensis.

森林可燃物载量调查专业性强,工作量大.无人机多光谱遥感可获取较大范围森林影像,为计算森林地表可燃物载量提供新的思路.试验区建立在广东省佛山市高明区,测得试验区平均地表可燃物载量高达每公顷39.33 t,且湿地松林Pinus elliottii地表可燃物载量最高.研究发现NDVI及EVI两种植被指数与森林地表可燃物载量之间存在中等强度的相关性,并建立了NDVI(X)与森林地表可燃物载量(Y)的回归模型:Y=-5.9354X+8.4663,以及EVI(X)与森林地表可燃物载量(Y)的回归模型:Y=-5.8485X+6.7271.研究还发现NDVI与地表可燃物载量的线性关系更为显著.

伴随着全球气候变暖的加剧,森林火灾的严重程度也将大幅增加,尤其是伤亡人数的增加,引起政府及学者们的高度关注.为此,开展森林防灭火督导、强化责任落实,把森林防灭火工作落到实处具有重要意义.本文通过对河源市、梅州市开展森林防灭火督导工作,解析了森林防灭火工作的成效与亮点,指出了目前森林防灭火工作存在的一些问题,结合广东省森林防灭火特点,在森林火灾示范建设、火灾隐患排查、严格火源管控、营造防火氛围、完善应急分级响应机制、加强两支队伍建设等方面提出了做好森林防灭火工作的建议与对策.

桉树Eucalyptus spp.人工林蓄积调查是林业生产经营的重要工作,无人机机载激光雷达能够自动获取大面积桉树人工林的激光点云数据,为计算桉树蓄积量提供新的方法.研究通过试验样地实际数据,建立了桉树树高(X)与胸径(Y)的回归模型:Y=3.6116e0.0674X,并结合激光雷达软件获取的株数、树高估算样地总蓄积量.比较激光雷达测量与实地测量结果发现,激光雷达测量的株数比实测株数少27.09％,平均树高高8.67％,平均胸径大8.25％,总蓄积量小22.68％.因此,对于大尺度获取桉树成熟林的总蓄积量V,可以使用V=V0/(1-22.68％)对激光雷达测量的总蓄积量V0进行修正.

森林防灭火工作事关国家生态安全、人民生命财产安危和社会大局稳定.针对广东森林生态建设现状以及森林防灭火面临新形势,剖析了目前存在的森林大火风险、扑火安全风险、应急能力风险等.最后针对广东森林防灭火工作存在的实际问题,有的放矢提出了森林防灭火工作的对策.

针对四川凉山州“3·30”森林火灾及扑火人员伤亡事件从客观与主观两方面进行了原因剖析,提出了7个方面的森林防火工作建议与对策.

森林火灾作为森林非连续的干扰因子,是生物地球化学循环的驱动因子,显著改变生态系统的结构和功能及养分循环与能量传递,引起森林碳库与碳分配格局的变化,进而影响森林演替进程及固碳能力.该研究以广东省马尾松(Pinus massoniana)次生林为研究对象,采用相邻样地比较法和空间代替时间法,以野外调查采样与室内试验分析为主要手段,定量研究突发性森林火灾对土壤有机碳密度的影响,探讨森林火灾对土壤有机碳固持的影响机制.结果表明:与对照相比,森林火灾后的幼龄林、中龄林和成熟林的土壤有机碳密度分别为35.12、40.80和52.34 t·hm-2,依次降低了10.93％、8.52％和7.56％.相比对照,幼龄林、中龄林和成熟林土壤剖面(0-60cm)的土壤有机碳密度变化范围分别为5.04-7.76、5.26-10.27和6.33-13.58 t·hm-2,依次降低了2.51％-16.83％、1.31％-11.85％和1.09％-12.50％;森林火灾显著降低了幼龄林和中龄林0-30 cm的土壤有机碳密度,显著降低了成熟林0-20 cm的土壤有机碳密度.马尾松次生林土壤有机碳密度与土壤理化性质具有显著相关关系.通径分析表明,对照样地和过火样地中,土壤全氮含量均对土壤有机碳密度的直接作用最大,土壤细根生物量对土壤有机碳密度的直接作用较小,但其通过土壤全氮含量对土壤有机碳密度的影响均表现在间接作用上.嵌套方差分析表明,土壤深度解释了土壤有机碳密度变异的70.60％,林龄解释了其变异的25.35％,森林火灾解释了其变异的2.34％.研究发现:森林火灾减少了马尾松次生林各林龄的土壤有机碳密度.在水平方向上,随着林龄增长,土壤有机碳密度的减少幅度降低;在垂直方向上,土壤有机碳密度随着土壤土层深度加深而降低,且随林龄增长减少幅度下降.研究森林火灾对森林生态系统土壤有机碳的影响,有助于理解森林生态系统土壤碳固持和碳循环过程,对制定旨在减缓全球变化的科学合理的林火管理策略具有重要意义.

森林火灾是森林生态系统中的重要干扰之一,深刻影响着土壤生物和非生物特性动态变化,进而影响生态系统养分循环和平衡.选择森林火灾典型分布区域,选取相似立地条件的具有南方代表性的不同发育阶段(不同林龄:幼龄林、中龄林和成熟林)的马尾松(Pinus massoniana)次生林,在火烧迹地(过火样地)及相邻未烧林分(对照样地)进行野外调查和采样,定量研究森林火灾对土壤理化性质的影响.森林火灾增加了马尾松次生林不同林龄的土壤容重、土壤pH值和土壤全磷,降低了不同林龄的土壤含水率、土壤全氮和土壤有机碳含量;提高了土壤C/N比,减少了C/P比和N/P比,且土壤含水率、土壤全氮、土壤全磷和土壤有机碳含量均随着林龄增长而增加,土壤容重和土壤pH值随林龄增长而减少.相关分析表明,土壤细根生物量与过火样地的土壤容重和土壤pH值呈负相关,而与土壤全氮、土壤全磷和土壤含水率呈极显著正相关(P<0.01).不同林龄土壤有机碳含量与土壤全氮耦合性较高.嵌套方差分析表明,引起马尾松次生林土壤理化性质变异的原因是不同林龄、不同土壤深度和森林火灾,林龄和土壤深度解释了土壤理化性质的10.80％—69.80％,森林火灾解释了土壤理化性质变异的2.50％—11.20％.森林火灾对不同林龄马尾松次生林的土壤理化性质均产生影响.马尾松次生林土壤含水率、土壤全氮、土壤全磷和土壤有机碳含量均呈现为随土壤土层深度加深而减少的趋势,而土壤容重和土壤pH值则表现为随土壤土层深度加深而增加的趋势.研究结果进一步量化了森林火灾对土壤理化性质的影响,可为火烧迹地恢复、森林碳汇管理、林业可持续发展提供科学支撑.

随着气候变暖加剧,全球森林火灾灾害发生的频率与强度亦随之增加,世界各地森林火灾潜在的危险将长期存在,严重程度也将大幅增加.森林火灾对森林生态资源和全球气候产生了重大影响,由于其突发性强、破坏性大、处置救助极为困难,是当今世界最为严重的生态灾害和突发性公共事件之一.森林火灾发生发展规律是森林火灾预防与扑救的重要依据,加强其规律研究有利于有的放矢地开展森林防灭火工作.针对气候变化现状及发展态势,结合气候变化背景下国内外森林火灾现状,系统论述了气候变化对我国森林火灾发生发展规律的影响,主要阐述了气象条件影响森林火灾的发生,气候影响森林可燃物,气候影响森林火源,气象影响森林火行为,气候决定森林火灾周期以及气候变化对森林火灾时空分布规律的影响.在全球气候变暖的背景下,从解析我国森林火灾发生规律入手,通过气候变化背景下我国森林火灾发生规律的研究,客观认识我国和各地区森林火灾发生发展规律,从而为国家和地方各级政府有效开展森林火灾灾害防治和应急管理工作、切实保障社会经济可持续发展提供科学决策依据.

以韶关市为例,系统介绍森林防火工作的亮点和成效.韶关市清明节期间以森林防火督导工作为先导,森林防火工作早部署早安排,狠抓森林防火责任和具体工作落实,压实基层森林防火责任,有序开展清明节期间的森林防火工作.最后探索性地提出了适合当地实际,在森林火灾预防、队伍装备建设、制度建设、法律责任追究方面建立健全森林防火长效机制,完善标本兼治的森林防火措施,切实把防火的重点转移到"预防为主"的轨道上来.

森林火烧迹地面积的传统调查方法存在劳动强度大、效率低、数据可靠性不高等问题.为解决上述问题,研究设计了无人机荷载多光谱传感器对森林火烧迹地面积进行调查的方法,并利用野外实验对该方法进行了初步验证.结果表明该调查技术可快速准确获取较大范围的森林火灾火烧迹地面积,精度可达94.44％,提高了火烧迹地调查的效率.

2019年春季以来,我国山西、四川、内蒙古、河北多地频发森林火灾,山西、四川、陕西、云南、辽宁等地先后发生重大森林火灾,导致了森林资源及生态环境的严重损失,造成严重人员伤亡.面对当前我国森林火灾频发和严重危害,为应对当前森林火灾的多发态势,有必要探讨森林防灭火对策.通过解析当前森林火灾多发原因,分析当前存在的主要薄弱环节和问题,从而对我国森林防灭火工作提出了应对措施.最后,对我国森林防灭火工作提出建议.

红外热成像仪在森林火灾远程视频监测中应用广泛,但每种红外热成像仪性能各异,需要对其林火识别性能进行测评,以便为红外热成像仪的选型提供依据.文章提出了一种基于红外裸数据的红外热成像仪测评方法.该方法从火点的辨识度和理论可识别距离两方面对不同的红外热成像仪进行性能测评和实验测试,可客观地评价红外热成像仪对林火的识别能力.

以2017年8月23日珠海市遭受强台风"天鸽"的正面袭击后凤凰山森林可燃物调查和2017年12月20日发生在凤凰山森林火灾火行为变化为基础,根据台风灾害前后森林可燃物载量的变化状况,分析了的台风灾害后林火特点,比较了不同灭火方法对灭火效果的差异.结果表明,随着台风灾害后林火燃烧环境的改变,导致灭火的难度增加,采取以水灭火和直升机吊桶洒水灭火,能有效扑灭可燃物大幅度增加后的森林火灾,灭火效果较好.研究发现,台风灾害后导致的森林可燃物大量增加,影响林火燃烧环境和林火行为,对于此类的森林火灾,应根据林火环境特征采取针对性灭火措施,从而提高灭火效果,有效保护森林资源.

This paper uses SWOT analysis to analyze strengths, weaknesses, opportunities and threats of forest aviation fire protection development in Guangdong. Its strengths are: governments at all levels attach im-portance to aviation forest fire protection, establish working mechanisms of aviation forest fire protection with helicopters and aviation forest fire protecting bases which have the ability of mobile refueling and forest fire air defense. Weaknesses are: the construction process of aviation forest fire protecting bases and landing points are slow, techniques of aviation forest fire protecting team are weak, lack of fuel supply and air round workers do not have special service grants. Opportunities are: ecological civilization construction provides new opportunities, rich water supply offers convenience for nearby water gathering, and the People's Government of Guangdong province has formulated measures for the examination of the responsibility system for forest resources, and strengthened its accountability. Threats are: the helicopter has few sources which cannot meet the needs of aviation forest fire protection, and the air space management is complicated which limits the flexibility of helicopter. On the basis, the paper puts forward some countermeasures for the development of Guangdong forest aviation fire protection:strengthen the base construction, improve the range of aviation forest fire protection; increase the number of heli-copters, improve the prevention and control force of aviation fire protection region; strengthen the construction of talent team, constantly improve protection work level; strengthen communications to improve emergency rescue capabilities; strengthen information technology construction, and constantly improve the technology level of avia-tion fire protection.