坡位在思茅松林计划烧除中对土壤有机碳储量的影响探析

比较思茅松常规林和计划烧除林上坡、中坡和下坡3个坡位腐殖质层厚度、载量和有机碳储量,以及0～60cm层次土壤有机碳含量和储量,分析坡位在思茅松林计划烧除中对土壤有机碳储量的影响。实验数据表明:思茅松林3个坡位计划烧除后腐殖质层厚度、载量、有机碳储量均增加显著(P<0.05),分别增加了0.55cm,2.298t/hm2,1.466t/hm2;0～60cm层次各个相同坡位土壤平均有机碳含量和储量增加均极显著(P<0.01),增幅均为下坡>中坡>上坡,增加值分别为0.581,0.505,0.482;44.218,41.696,32.492t/hm2。这些实验数据说明计划烧除可增加森林土壤有机碳储量,选择下坡和中坡进行计划烧除可获得更好的固碳效率。     

毛竹、杉木人工林生态系统碳平衡估算

采用CID-301PS光合测定仪,对湖南会同林区毛竹和杉木人工林土壤CO2排放动态进行观测,并结合现存生物量调查,对其生态系统碳平衡特征进行估算.结果表明:毛竹和杉木林生态系统碳贮量分别为144.3和152.52 t·hm-2,并且其碳贮量空间分布格局基本一致,土壤层是主要部分,其次为乔木层,凋落物层和林下植被层所占比例最小.毛竹林土壤层有机碳贮量占76.89%,乔木层占22.16%,凋落物和林下植被层分别占0.51%和0.41%;杉木林土壤层碳贮量占62.03%,乔木层占34.99%,凋落物和林下植被层分别占2.28%和0.70%.毛竹林和杉木林生态系统年固定CO2总量分别为38.87和26.95 t·hm-2a-1,但其每年以土壤异养呼吸和凋落物呼吸的形式排放CO2的量分别为24.35和15.75 t·hm-2a-1,毛竹林和杉木林生态系统年净固定CO2的量分别为14.52和11.21 t·hm-2a-1,折合成净碳量分别为3.96和3.07 t·hm-2a-1.     

间伐对杉木人工林生态系统碳贮量及其空间分配格局的影响

对间伐5年后的湖南会同杉木人工林生态系统碳贮量及其空间分配格局进行了研究。结果表明:(1)无论是间伐区还是对照区,单株杉木各器官的碳贮量以及乔木层各组分的碳贮量均与其生物量成正比,且均以树干的碳贮量最高,分别占单株杉木碳贮量和乔木层碳贮量的65.63%和64.99%以上,但间伐区单株杉木各器官碳贮量和乔木层各组分碳贮量的大小排序均与对照区有所不同。(2)间伐后,单株杉木的碳贮量增加了48.96 kg,增长了62.91%;但乔木层碳贮量下降了17.37%,减少了15.56 t.hm-2;林下植被碳贮量增加了1 399.42 kg.hm-2,增长了230.94%;杉木林生态系统的碳贮量减少了20.824 t.hm-2,下降了11.73%;其中植被层碳贮量减少了14.162t.hm-2,下降了15.70%,土壤层减少了8.61 t.hm-2,下降了10.09%,死地被物层增加了1.948 t.hm-2,增长了93.34%,且杉木林生态系统中碳贮量的空间分布格局发生了一定的变化。表明间伐可导致杉木人工林生态系统各组成部分的碳贮量及其空间分布格局发生不同的变化。     

便携式森林消防阻隔带在计划烧除中的应用

主要针对计划烧除中易引起失控跑火,造成森林资源破坏问题,在中条山国有林管理局范围内选取林缘、林农林牧接壤区、重点资源保护区,设置12块样地,进行了便携式森林消防阻隔带实用技术研究.研究通过标准地取样进行可燃物载量回归分析、人工和消防阻隔带开设隔离带对比、大气质量监测等,得出以下结论:(1)林缘地可燃物载量与灌木、草本相关性明显,活可燃物是影响林缘地可燃物载量的主要因素.利用回归模型可以科学确定森林消防阻隔带的可燃物载量使用上限.(2)采用森林消防阻隔带开设隔离带,比人工开设效率提高66.75%,且能够提高安全性.(3)森林消防带应用于计划烧除技术,对环境的负效应不显著,可以推广使用.     

海南岛尾细桉人工林碳贮量及其分布

基于海南西部沿海台地区、北部平原区、东部沿海台地区和中部山地区共18个调查点54个尾细桉人工林样地调查数据,分析海南尾细桉人工林的生物量、碳贮量、固碳能力及其区域空间分布特征。结果表明:海南尾细桉人工林生物量平均为49.72t·hm-2,乔木层(85.10%)>凋落物层(8.08%)>林下植被层(6.82%);尾细桉人工林生态系统碳贮量平均为88.84t·hm-2,乔木层为20.55t·hm-2(23.13%),林下植被层为1.55t·hm-2(1.74%),凋落物层为1.93t·hm-2(2.17%),土壤层(0～100cm)为64.81t·hm-2(72.96%);尾细桉各器官碳贮量以树干最大,占乔木层碳贮量的52.81%;海南尾细桉人工林生态系统年净生产力平均为17.56t·hm-2a-1,年净碳固定量平均为8.43t·hm-2,折算成CO2量为30.91t·hm-2a-1;整个海南尾细桉人工林生态系统碳贮量为2958.37万t,年净碳固定量为280.97万t·a-1;从不同区域来看,中部山地区尾细桉人工林固碳能力达11.89t·hm-2a-1,远高于北部平原区(8.97t·hm-2a-1)、西部沿海台...     

森林植被碳贮量估算及分析

文章基于岳阳市2009年森林资源统计数据,对全市森林植被类型的生物量、碳贮量和碳密度进行初步估算。结果表明:岳阳市森林植被碳贮量为9.238Tg,其中,平江县的森林植被C贮量最大,为3.606Tg,占总C贮量的39.03%。各森林类型的C贮量来看,松木林的C贮量最大,为2.754Tg,占总C贮量的29.81%。岳阳市森林植被平均C密度为16.02t.hm-2,各县市区森林植被的C密度为13.39~27.10t.hm-2,森林植被平均C密度最大是云溪区,为29.02t.hm-2,各森林类型中阔叶树的C密度最大,为27.24t.hm-2,是全市森林植被平均C密度的近2倍。       

湖南省森林植被的碳贮量及其地理分布规律

基于湖南省第4次(1990～1995年)森林资源调查资料,结合生物量测定数据,估算了湖南省森林植被的碳贮量和碳密度,分析了它们的地理分布规律和植被类型特性.结果表明:湖南省森林植被碳贮量为173.974 Tg,在14个地州市中,怀化市的森林植被碳贮量最大,为31.047 Tg,其它依次是永州市、郴州市和邵阳市,它们的森林植被碳贮量分别为21.527、19.306和19.239 Tg,各森林类型中,杉木林的碳贮量最大,为51.588 Tg,占湖南省碳贮量的29.65%;湖南省森林植被的平均碳密度为15.88 t·hm-2,各地州市森林植被的平均碳密度变化为12.01～17.95 t·hm-2,各森林类型中阔叶林的碳密度最大,为32.45 t·hm-2,是湖南省森林植被平均碳密度的2倍多.     

米槠天然林与人促更新林乔木碳贮量及分布特征

以米槠天然林和人促更新林为研究对象,研究米槠天然林与米槠人促更新林2个林分的乔木碳贮量及其不同径级、高度的分配特征。结果表明:米槠天然林碳贮量为193.66 t·hm-2,人促更新林碳贮量为141.34 t·hm-2。天然林径级呈波浪型分布,各径级(5~10 cm、10~15 cm、15~20 cm、20~25 cm、≥25 cm)碳贮量占总碳贮量比值分别为:2.85%、3.46%、6.55%、2.90%、84.24%;而人促更新林径级呈递增变化,各径级碳贮量分配没有天然林集中,各径级碳贮量占总碳贮量比值分别为:3.19%、4.98%、15.52%、36.85%、39.45%。在垂直方向上,2个林分碳贮量均随着高度级的增加而增加,且2个林分碳贮量最大值均出现在≥20 m高度级,碳贮量米槠天然林为117.54 t·hm-2、人促更新林为85.67 t·hm-2。     

豫南35年生马尾松林生态系统碳库特征及其分配

对豫南35年生马尾松林生态系统的生物量、碳贮量及其空间分布特征进行研究。采用分层切割法和相对生长方程计算乔木层生物量和林下植被生物量,C、N元素分析仪测定碳含量。研究结果表明:35年生马尾松林生态系统的总生物量平均为228.6 t.hm-2,其中乔木层生物量占88.9%,灌木层占7.7%,草本层占0.1%,凋落物层占2.7%;马尾松林生态系统总碳库为218.11 t.hm-2,其中植被总碳贮量为127.69 t.hm-2,土壤有机碳库为90.42 t.hm-2;乔木层碳库(115.52 t.hm-2)占生态系统碳库的52.96%,灌木层占3.80%,草本层占0.28%,现存凋落物层占1.50%,矿质土壤层碳库占生态系统碳库的41.46%。     

桤木人工林的碳密度、碳库及碳吸存特征

对不同年龄阶段桤木人工林生态系统碳密度、碳库和碳吸存的研究结果表明:桤木各器官的碳密度算术平均值随年龄的增长而增加,5,8和14年生的分别为478.8,485.7和495.8g·kg-1,变异系数在0.25%～9.58%之间,不同器官碳密度由高至低排序大致为:树干树枝树叶树根树皮,林下植被各组分和死地被物的碳密度随着林龄的变化规律不明显,土壤层(0～60cm)平均碳密度也随着林龄的增长逐渐增加,且在垂直分布上随着土层深度的增加而逐渐下降。不同器官的碳贮量与其生物量成正比例关系,随着林龄增长,乔木层碳贮量的优势逐渐增强,从5年生的25.88t·hm-2增加到14年生的49.63t·hm-2。桤木人工林生态系统的碳库主要由植被层、死地被物层和土壤层组成,按其碳库大小顺序排列为:土壤层植被层死地被物层,5,8和14年生桤木林生态系统中的碳库分别为95.89,122.12和130.75t·hm-2,土壤碳贮量占整个生态系统碳库的59.42%以上,且随着林龄增长,地上部分与地下部分碳贮量之比有逐渐下降的趋势,5,8和14年生桤木年净固定碳量分别6.51,6.26和7.82t·hm-2a-1。湖南省现有桤木林植被碳库为2.8034×106t,为其潜在碳库的47.51%。     

计划烧除的作用与应用研究综述

计划烧除是管理森林可燃物、预防森林火灾发生的有效方法,同时也是防治病虫害、促进山林复壮更新的重要措施。文章回顾了计划烧除在国内外的发展历史,阐述了计划烧除的应用及研究,总结出实施计划烧除的主要技术及操作程序,论述了国内目前计划烧除应用研究中存在的问题及发展前景。     

Potential CO2 emissions mitigation through forest prescribed burning: A case study in Patagonia, Argentina

Wildland fire is a natural force that has shaped most vegetation types of the world. However, its inappropriate management during the last century has led to more frequent and catastrophic fires. Wildland fires are also recognized as one of the sources of CO₂ and other greenhouse gases (GHG) that influence global climate change. As one of the techniques used to reduce the risk of destructive wildfires, prescribed burning has the potential of mitigating carbon emissions, and effectively contributes to the efforts proposed as part of the Clean Development Mechanism within the Kyoto protocol. In order to apply this concept to a real case, a simulation study was conducted in pine afforestation in the Andean region of Patagonia, Argentina, with the objective of evaluating the potential of prescribed burning for reducing GHG emissions. The scenario was established for a ten year period, in which simulated prescribed burning was compared to the traditional management scheme, which included the probability of annual average of wildfire occurrence based on available wildfire statistics. The two contrasting scenarios were: (1) managed afforestation, affected by the annual average rate of wildfires occurred in the same type of afforestation in the region, without prescribed burning, and (2) same as (1) but with the application of simulated prescribed burning. In order to estimate carbon stocks, and CO₂ removals and emissions, we followed the guidelines given for GHG inventories on the Agriculture, Forestry and Other Land Uses (AFOLU) sector of the International Panel on Climate Change (IPCC), while the terminology used was the established by IPCC (2003). Data of afforested area, thinnings, and biomass growth were taken from previous surveys in the study area. Downed dead wood and litter (forest fuel load, FFL) was estimated adjusting equations fitted to those fuels, based on field data. Results show that comparing the two scenarios, prescribed burning reduced CO₂ emissions by 44% compared to the situation without prescribed burning. The prescribed burning scenario represented about 12% of the total emissions (prescribed burning plus wildfires). Furthermore, avoided wildfires by simulated prescribed burning allowed an additional 78% GHG emissions mitigation due to extra biomass growth. Simulated prescribed burning in commercial afforestation of Patagonia appears to be an effective management practice not only to prevent wildfires, but also an efficient tool to mitigate GHG emissions. However, more studies in different scenarios would be needed to generalize these benefits to other ecosystems.     

北京西山林场火烧迹地植被更新及可燃物负荷量研究

在野外调查的基础上,对比研究了北京西山林场4种林分类型火烧迹地与对照林地上植被更新及可燃物负荷量的差异,对更新林分的潜在燃烧性进行了分析。所选择林分为侧柏林、油松林、刺槐林与白蜡林,其中侧柏林和油松林为2003年过火林分,刺槐林和白蜡林为2006年过火林分。火烧后,侧柏林采用人工更新,其它3种林分采用天然更新,研究结果表明:人工更新的火烧迹地上(侧柏林)植被多样性指数减少,总可燃物负荷量增加;而天然更新火烧迹地上(油松林、刺槐林及白蜡林)植被多样性指数增加,但总可燃物负荷量减少;火烧迹地可燃物负荷量的多少与更新时间成正比。总体而言,火烧更新使林地上易燃可燃物负荷量增加,难燃可燃物负荷量减少,从而使更新后林分的潜在燃烧性增加。     

Long-term impacts of prescribed burning on regional extent and incidence of wildfires—Evidence from 50 years of active fire management in SW Australian forests

Prescribed burning is advocated for the sustainable management of fire-prone ecosystems for its capacity to reduce fuel loads and mitigate large high-intensity wildfires. However, there is a lack of comprehensive field evidence on which to base predictions of the benefits of prescribed burning for meeting either wildfire hazard reduction or conservation goals. Australian eucalypt forests are among the very few forest types in the world where prescribed burning has been practised long enough and at a large enough spatial scale to quantify its effect on the incidence and extent of unplanned fires. Nevertheless even for Australian forests evidence of the effectiveness of prescribed burning remains fragmented and largely unpublished in the scientific literature.     

华山松人工林凋落物层细小可燃物含水率预测模型研究

在防火期2~5级火险天气条件下,在华山松人工林测定了153组林内气温(x1)、相对湿度(x2)、凋落物表面温度(x3)、腐殖质层表面温度(x4)、凋落物层厚度(x5)、可燃物含水率(y)数据,建立了华山松林细小可燃物含水率预测的多元线性回归模型。分析表明,影响华山松林凋落物上层易燃可燃物含水率的因子依次为:x3>x2>x4>x1。应用该模型,可以用易于获取的火环境和可燃物因子来预测可燃物的含水率,为合理开展林火预测预报、计划火烧、营林用火等提供依据。     

Climate and recent fire history affect fuel loads in Eucalyptus forests: Implications for fire management in a changing climate

Predicted changes to global climates are expected to affect natural fire regimes. Many studies suggest that the impact of these effects could be minimised by reducing fuel loads through prescribed burning. Fuel loads are dynamic and are affected by a range of factors including fire and climate. In this study, we use a 22-year dataset to examine the relative influence of climate and fire history on rates of litterfall and decomposition, and hence fuel loads, in a coastal Eucalypt forest in south-eastern Australia. Litterfall and decomposition were both affected by temperature, recent rainfall and fire history variables. Over the study period prescribed burning immediately reduced fuel loads, with fuel loads reaching pre-burn levels within 3 years of a fire. Modelling fuel loads under predicted climate change scenarios for 2070 suggests that while fuel loads are reduced, the levels are not significantly lower than those recorded in the study. Based on these predictions it is unlikely that the role or value of prescribed burning in these forests will change under the scenarios tested in this study.     

林火研究综述(Ⅰ)——研究热点与进展*

在危害森林的诸因子中火灾是一种最具破坏性的灾害。各林业先进国家都非常重视林火研究工作。森林防火是一门综合性的科学，其研究热点包括基础研究和应用研究。近些年林火研究涉及国家森林火险等级预报、林火控制技术、雷击火自动定位系统、遥测自动林火天气站网、火发生与火行为规律、计划烧除、火生态、可燃物燃烧过程、灭火喷洒技术、烟尘特征和扩散等。     

林火排放细颗粒污染物（PM2.5）研究进展

森林火灾是一种突发性强、随机性高、扑救极为困难的自然灾害，在森林燃烧过程中可释放出高浓度PM_2.5颗粒物。PM_2.5是除直接烧伤和窒息外，对森林火灾扑救人员生命安全造成巨大威胁的重要污染物之一，也会给林区居民身心健康带来严重危害。文中结合国内外以森林火灾、计划烧除、室内模拟燃烧等为实验手段的森林燃烧研究，总结森林燃烧释放PM_2.5的采样方法、成分分析、扩散研究、控制方法等研究进展，分析影响森林燃烧释放PM_2.5的气象因素、可燃物特征、林火行为等因素，以期为提高森林火灾扑救效率、降低火灾扑救过程中的伤亡事故以及后续相关研究提供参考。     

Forest management with wildfire risk,prescribed burning and diverse carbon policies

Forests absorb carbon dioxide through photosynthesis and also can release it back into the atmosphere through natural disturbances and management activities. In this study, the impact of different carbon policies on a landowner's management decisions is analyzed at the stand level. Wildfires as a random natural phenomenon and forestry prescribed burning as a fuel treatment tool are all considered within the framework of a generalized Faustmann model. The results reveal that harvesting rotations and land values can be affected by the level and pattern of wildfire risk, and additionally, the consideration of carbon in various policies. In response to different carbon policies, the optimal time of prescribed burning only varies slightly, but its intensity can experience much larger variations. If the landowner needs to pay for carbon emission from prescribed burning but not from a wildfire, the optimal strategy is to conduct the prescribed burning more lightly and later than in the base scenario. Overall, participation in a carbon program results in a higher land expectation value, which is beneficial to the landowner. These research findings are helpful for understanding the relation between carbon policies and the behavior of landowners, and furthermore, for improving carbon policy designs.