黄淮海平原主要农林复合树种的含碳率研究

为了准确计量黄淮海平原地区农林复合系统的碳汇功能,指导固碳树种的选择,分析了黄淮海平原20种主要农林复合树种不同器官的含碳率和10种典型树种生物量,计算了平均含碳率和平均加权含碳率。结果表明,各树种器官含碳率在34.19%~49.19%之间,树干的平均含碳率为44.12%,树枝的平均含碳率为45.51%,叶的平均含碳率为45.07%,根系的平均含碳率为39.84%。各树种平均含碳率在40.03%~47.94%之间,枣树平均含碳率最高,为47.94%,柿树最低,为40.03%。全部20种主要农林复合树种的平均含碳率为43.57%,可以作为黄淮海平原地区森林平均含碳率。10种典型树种平均加权含碳率栾树最高,为47.32%,柿树最低,为38.82%,和平均含碳率差距在0.11%~1.73%之间。从树种含碳率来看,栾树、107杨、泡桐、国槐、苦楝、大叶女贞和枣树可作为黄淮海平原农林复合系统优先选择的固碳树种。     

新疆西伯利亚云杉含碳系数分析

以新疆西伯利亚云杉为对象,运用假设检验与回归分析,对其含碳系数进行逐步分析。结果表明:干材上部、根茎的含碳系数大于同一器官其他部位;地上部分平均含碳系数为0.456 5;全株不同器官平均含碳系数为0.461 9,大小顺序为干皮树叶树枝树根干材;云杉各器官及全株含碳系数相对稳定,不随胸径、树高、年龄等因素变动。建议根据不同树种采用相应实测含碳系数。     

科尔沁大青沟3种群落乔木层优势树种含碳率分布特征的研究

以科尔沁大青沟水曲柳、蒙古栎及大果榆群落乔木优势树种为研究对象,采用湿烧法实测优势树种各器官含碳率,研究了不同树种及同一树种不同器官含碳率的分布特征。结果表明:1)大果榆不同龄级枝条含碳率的变化幅度与蒙古栎的变化幅度差异最大(2.46%),3种树种各自不同龄级枝条含碳率存在显著差异;2)3种树种不同径级根系含碳率存在差异,其中蒙古栎根系的平均含碳率(50.60%)明显比大果榆(46.42%)、水曲柳(46.25%)的高;3)3种树种器官平均含碳率变化范围分别为48.17%⁵3.92%,45.58%53.92%,45.58%⁵1.44%,46.25%51.44%,46.25%⁵1.68%。由此可知,不同树种因受遗传因素影响,其含碳率存在差异,即使是同一树种含碳率受器官功能不同、主要组成成分及器官生长年限的影响,各器官含碳率也存在差异。     

毛竹等11种浙江省碳汇造林树种含碳率分析

采用重铬酸钾硫酸氧化加热法对毛竹等11种浙江省碳汇造林树种不同器官的含碳率进行了测定,并用聚类分析法分析,得到以下结论：浙江省主要树种含碳率可以分为四种类型：第一类是毛竹,根部含碳率高,叶部含碳率低;第二类为松类、檫木和杉木,含碳率高;第三类为硬阔中的木荷、青冈和软阔中的桤木．生长速度较快;第四类为软阔中的枫香和硬阔中的山杜英。各树种各部分含碳率均在45．21％～53．88％之间,毛竹、针叶树种各组分的含碳率总体上比阔叶树种高1％～3％,毛竹林、针叶林的含碳率远远高于阔叶林。各器官含碳率可以分为3类：其中干部归为一类,根部和枝归为一类,叶部独立为一类。     

黑龙江省典型森林类型主要树种及林地土壤含碳率测定研究

每种林分类型主要树种的含碳率是研究该林分类型碳汇量的关键因子。利用从黑龙江省6个地市不同林分类型采集到的18个树种各器官（干、枝、叶、根）以及各林分类型的林下植被、枯枝落叶及土壤各层的样品,采用重铬酸钾-硫酸氧化湿烧法进行含碳率测定分析,结果表明：18个树种不同器官含碳率的变化范围为40．52％～53．23％,平均含碳率为46．82％;各林分类型枯枝落叶含碳率较高,达到35．76％～52．57％,土壤A层含碳较低,B层较A层更低。     

大兴安岭1980-1999年乔木燃烧释放碳量研究

在黑龙江省大兴安岭森林火灾时空格局研究的基础上,通过野外调查采样和室内试验分析相结合的方法研究主要乔木树种1980-1999年间的碳释放量.结果表明:1)大兴安岭林区20 a间各林型过火面积分别为:兴安落叶松林437 947.34 hm2,樟子松林20 938.70 hm2,针阔混交林142 526.95 hm2,白桦林168 531.57 hm2,蒙古栎林1 374.97 hm2.2)通过MultiC/N3000测定得出各树种地上部分含碳率平均数值,兴安落叶松为42.34%,樟子松为41.20%,白桦为42.01%,山杨为39.21%,蒙古栎为39.79%,2种针叶树平均含碳率为41.77%,3种阔叶树种林分平均含碳率为40.30%.主要乔木树种地上部分平均含碳率值均小于目前国际通用的0.45. 3)大兴安岭林区20 a间各类型森林火灾乔木损失生物量为7.31×106～11.57×106 t.其中,落叶松林乔木损失量占总损失生物量的61.80%～62.38%;其次为白桦林,占总损失生物量的26.53%～26.81%.4)大兴安岭林区20 a森林火灾乔木释放碳量为3.04×106～4.78×106 t,平均每年释放碳量为1.52×106～2.39×106 t,占全国森林火灾释放碳量的7.51%～11.81%.各乔木树种中落叶松火灾释放碳的比例最高,约占总释放量的2/3左右;其次为白桦,占总释放量的1/4左右;其他树种释放较少,共占1/12左右.研究结果将为正确认识大兴安岭森林火灾碳平衡及评价森林火灾对全球生态环境影响提供科学依据.     

河北太行山区典型水土保持林乔木层生物量及碳储量研究

以河北太行山区4种典型水土保持林为研究对象,对混交林(栓皮栎-侧柏)、油松林、栓皮栎林和刺槐林的乔木层各器官生物量、含碳率以及碳储量进行比较研究。结果表明:混交林、油松林、栓皮栎林和刺槐林生物量分别为51.94,86.40,90.19,18.08t/hm^2,栓皮栎林和油松林生物量高于4种水土保持林生物量的均值(61.65t/hm^2),而混交林和刺槐林生物量分别占生物量均值的84.25%,29.33%。不同林分各器官在乔木层生物量中分配顺序均表现为树干>树根>树枝>树叶。4种典型林分各器官含碳率分别为45.16%~58.93%,58.48%~64.61%,51.16%~58.37%,52.35%~62.30%。4种典型林分碳储量为10.10~53.85t/hm^2。不同林分类型各器官碳储量与生物量呈正比关系,与生物量趋势基本相同,碳储量大小表现为油松林>栓皮栎林>混交林>刺槐林。     

福建四种乔木树种燃烧释放污染物排放因子研究

福建位于我国亚热带地区,其林火发生频率高且强度低;导致大量污染物释放,对大气环境和森林生态系统产生不良影响。本研究通过自主设计的室内模拟实验,实测福建省杉木(Cunninghamia lanceolata)、马尾松(Pinus massoniana)、桉树(Eucalyptus robusta)和樟树(Cinnamomum camphora)四种主要乔木树种不同器官(叶和枝)燃烧时CO、CO_2、NO_x、C_xH_y和PM2.5等污染物的排放因子,并分析不同树种及不同器官之间污染物排放强度的差异性。结果表明,不同乔木树种的不同器官在燃烧时释放各污染物的平均排放因子范围分别为:CO为102.88~116.10 g/kg;CO_2为814.50~1 212.57 g/kg;NO_x为0.52~3.47 g/kg;C_xH_y为20.84~61.87 g/kg;PM2.5为5.34~14.61g/kg。此外,不同树种枝的排放因子之间也存在显著性差异。其中桉树枝燃烧释放的含碳气体排放因子显著高于其它树种,而马尾松枝燃烧时释放的氮氧化物和PM2.5排放因子最高。阔叶树的枝和叶燃烧时释放的CO显著高于针叶树,而PM2.5的排放则显著低于针叶树。研究揭示了福建主要乔木树种不同器官的燃烧释放污染物特性,为区域生态环境评价提供依据。     

植物有机碳测定研究进展

植物有机碳含量是研究森林碳储量的关键因素之一, 文中总结了近20年森林植被含碳率研究的状况、存在问题和发展趋势。指出中国植被含碳率的研究主要集中在华北、华东、西北和西南的部分地区。目前, 测定植物有机碳主要有湿烧法和干烧法, 另外也有少部分根据分子式或重量法计算植物有机碳含量。森林生态系统中不同树种、不同树种不同器官、相同树种不同器官的含碳率差异显著, 另外, 木质组成、器官的相对位置、干燥温度、地区差异、种源、气候、立地等因素对含碳率有一定影响。林下植被是森林碳储量研究的重要组成部分, 但现有研究很少涉及林下各层植被。指出未来的研究重点为:1)相同树种在不同区域的含碳率稳定性; 2)在提高碳储量估算精度的前提下精炼含碳率的影响因子; 3)补充时间序列上含碳率的差异性; 4)加强对林下植被含碳率的研究。     

基于国家森林资源清查数据的不同生物量和碳储量估计方法的对比分析

[目的]通过对不同生物量和碳储量的估计方法进行对比分析,为确定在国家森林资源清查中生物量和碳储量的具体估计方法提供依据。[方法]以广东省2012年森林资源清查的100个杉木林和80个马尾松林的实测样地资料为基础,利用近年来我国建立的主要树种立木生物量模型,对改进IPCC法、生物量模型法和转换因子连续函数法(即方精云法)3种方法按一元和二元模型共6种方案进行了对比;同时,基于改进IPCC法一元和二元模型的生物量估计值,用平均含碳系数法、组分含碳系数法和固定含碳系数(0.5或0.47)法分别对碳储量进行估计。[结果]用二元生物量模型法得到的杉木林和马尾松林样地的总生物量分别为320 Mg和331 Mg,一元生物量模型法的结果分别相差0.9%和6.2%;改进IPCC法的估计结果,采用二元和一元模型时杉木林分别相差-3.6%和-11.9%,马尾松林分别相差-8.5%和-19.6%;而方精云法的估计结果,采用二元和一元模型时杉木林分别相差6.65倍和6.60倍,马尾松林分别相差-14.3%和-18.0%。平均含碳系数法和组分含碳系数法的碳储量估计结果,杉木林仅相差0.2%,马尾松林相差约0.4%;固定含碳系数法的估计结果因树种而异,对杉木林要低估0.6%5.4%,对马尾松林要低估3.3%9.1%。[结论]对生物量的估计,采用生物量模型法准确性最高,而林木水平的生物量模型其预估精度要高于林分水平的模型;IPCC法是基于材积源的通用方法,将其中的缺省参数改进为可变参数模型,可大大提高方法的适应性;方精云法只是基于IPCC法所建立的林分水平模型在大尺度上的一种具体应用方法,其精度要低于林木水平的生物量模型法,不适于中小尺度应用。对碳储量的估计,采用平均含碳系数法与组分含碳系数法差异很小,但采用固定含碳系数法则误差较大。     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.