喀斯特地区不同植被恢复模式幼林生态系统碳储量及其空间分布

研究喀斯特地区4种植被恢复模式幼林生态系统碳含量、碳储量及其空间分布特征。结果表明:不同树种同一器官中的碳含量存在差异;同一树种不同器官中的碳含量也不同,除楸树外,3种树地上部分各器官的碳含量普遍高于地下部分(根);不同树种各器官碳含量的变异系数为0.88%～7.02%;林下灌木层、草本层、死地被物层的平均碳含量分别为309.70～461.02,335.44～569.61和307.01～400.88g·kg-1,植被恢复初期,柏木林地、楸树林地土壤有机碳含量分别比对照地提高了56.37%和33.49%,而花椒林地下降了2.09%;不同林地土壤有机碳含量均随土壤深度的增加而逐渐下降;4种林分乔木层的碳储量表现为楸树林>车桑子林>花椒林>柏木林;楸树、花椒和柏木林地0～20cm土层碳储量分别为113.061,82.424和126.841t·hm-2,与对照地相比,楸树和柏木林地土壤碳储量分别提高了31.14%和47.13%,而花椒林地却下降了4.39%,车桑子林地0～10cm土层碳储量为50.517t·hm-2;楸树林、花椒林、柏木林和车桑子林生态系统碳储量分别为117.207,84.117,127.919和53...     

四川主要针叶树种含碳率测定分析

应用湿烧法对四川13个主要针叶树种不同器官的有机含碳率进行了测定,同时利用生物量资料对林分平均含碳率进行了分析。实验结果表明:各树种林分平均含碳率分别为落叶松0.5259、火炬松0.5262、华山松0.5437、马尾松0.5144、湿地松0.5216,云南松0.5281、油松0.5314、柏木0.5211、杉木0.5365、柳杉0.5479、水杉0.5489、冷杉0.5050、云杉0.5160;种内各器官的含碳率变动系数在1.90%~5.96%之间;器官含碳率的种间变动系数在2.28%~5.37%。针叶树种器官碳的平均含碳率普遍高于阔叶树种0.18%~7.45%;相应的针叶林分的平均含碳率也高于阔叶林。     

广西主要乔木树种碳含量测定

在广西收集10个树种共62株，分别对叶、枝、皮、干采样，采用 K2 Cr2 O7-H2 SO4容量法测定碳含量。结果表明：树干碳含量约比其他器官高5％左右，树叶、树枝和树皮无显著差异，但不同树种的器官碳含量有一定差异；10个树种碳含量进行生物量加权平均计算，综合碳含量﹥470 g/ kg，针叶树高于阔叶树，慢生树种高于速生树种。     

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。     

广东毛竹碳含量测定分析

为了获得广东地区毛竹(Phyllostachys pubescens)的碳含量以及准确估算广东地区毛竹的碳储量和碳汇能力,采用湿烧法对广东省龙川县、南雄市5~6 a生毛竹不同器官、不同径阶、不同竹干高度的碳含量进行分析。结果表明:毛竹的平均碳含量为509.91 g/kg,毛竹不同器官碳含量大小关系为枝(524.51 g/kg)干(523.24 g/kg)根(504.04 g/kg)叶(487.85 g/kg);毛竹的竹秆和枝的碳含量差异均不显著,竹秆和枝与其它器官的碳含量差异均显著(P0.05);毛竹竹秆不同高度位置碳含量差异不显著。以上结果说明,毛竹不同器官之间碳含量存在差异性。为了提高对某一区域毛竹碳储量估算的准确度,需对该区域毛竹各器官碳含量进行精确的地面实测。     

广东8种主要乔木树种碳含量测定分析

应用湿烧法对广东地区8种主要乔木树种(马尾松、速生相思、杉木、桉树、湿地松、硬阔类、软阔类、黎蒴)的碳含量进行了测定,并对不同树种、不同器官、不同径阶、不同树干高度的碳含量进行分析。结果表明:1)不同树种碳含量高低依次为湿地松杉木马尾松速生相思硬阔类桉树软阔类黎蒴;针叶树的碳含量大于阔叶树;2)不同器官碳含量大小关系为树叶树枝树皮树干树根,器官碳含量遵循由上到下,呈现由外到里逐渐减少的趋势;3)不同树种不同树干高度位置碳含量十分接近,变异系数均在3.64%以内;4)研究区域树木碳含量受径阶影响很小,碳含量变化幅度小,同一树种不同径阶下不同器官的碳含量变化情况呈现多样性,同一树种内不同径阶和不同高度位置碳含量呈先上升后下降的趋势。径阶与树干高度位置碳含量没有相关性,但总体上相同高度位置下样品碳含量随着径阶的增加先上升后下降。以上结果说明,不同树种之间,相同树种内部不同器官之间,以及不同特性相同树种之间碳含量存在差异性。对各地区、各树种、各森林生态系统的碳含量进行全方位精确测定,可为提高估算其碳储量的准确度提供科学依据。     

广东毛竹碳含量测定分析

为了获得广东地区毛竹(Phyllostachys pubescens)的碳含量以及准确估算广东地区毛竹的碳储量和碳汇能力,采用湿烧法对广东省龙川县、南雄市5~6 a生毛竹不同器官、不同径阶、不同竹干高度的碳含量进行分析.结果表明:毛竹的平均碳含量为509.91 g/kg,毛竹不同器官碳含量大小关系为枝(524.51 g/kg)>干(523.24 g/kg)>根(504.04 g/kg)>叶(487.85 g/kg);毛竹的竹秆和枝的碳含量差异均不显著,竹秆和枝与其它器官的碳含量差异均显著(P<0.05);毛竹竹秆不同高度位置碳含量差异不显著.以上结果说明,毛竹不同器官之间碳含量存在差异性.为了提高对某一区域毛竹碳储量估算的准确度,需对该区域毛竹各器官碳含量进行精确的地面实测.     

树木园不同树种人工林土壤养分变化特征

人工造林对土壤养分变化的影响一直是森林培育过程中受到关注的问题之一。采用典型样地取样和室内分析的方法,研究了树木园不同针阔叶树种林地土壤养分含量的变化。结果表明:相同立地条件下,人工造林后土壤养分的表聚性明显,且树种不同对土壤养分含量的影响不同;栽植针叶树种主要是改善浅层土壤全氮含量,并明显提高0～40 cm土层有机质、速效氮、速效磷含量,而对土壤全磷、全钾含量影响不明显,甚至降低了土壤全磷含量;而栽植阔叶树种后,不同土层深度土壤有机质、全氮、速效氮和速效磷含量均高于对照样地,且对改善土壤全氮、速效氮和速效磷含量的效果明显好于针叶树种。内蒙古林科院树木园不同树种林地土壤养分含量明显增加,尤其是增加表层0～5 cm有机质、全氮、速效氮和速效磷含量,而阔叶树种对增加全磷、速效磷含量好于针叶树种。     

几种固氮树种凋落物分析研究

对福建沿海山地人工混交林中的伴生树种台湾相思、杨梅等固氮树种的凋落物数量及氮含量进行了初步研究,并与主要造林树种的凋落物氮含量进行比较分析。结果表明:造林七年林分中台湾相思和杨梅年凋落物量分别为每公顷1177和1288公斤,其氮含量分别为2.32%和1.66%,显著高于非固氮阔叶树种组和针叶树种组凋落物氮含量的平均值。     

广西主要树种热值研究

探讨树种不同器官间的植物热值规律,可为这些树种的能量特征和生态效率研究提供基础资料和科学依据。通过对广西12个主要树种不同器官的热值测定,结果表明：各主要树种的加权平均干重热值和去灰分热值分别在18.56～20.41 kJ/g和19.11～20.57 kJ/g;树种各器官热值表现为叶片含量最高,各器官热值含量顺序一般为叶〉枝〉皮〉干,或叶〉皮〉枝〉干;树种各器官的灰分含量在0.18%～14.48%,树种各器官灰分含量一般表现为叶〉皮〉枝〉干。     

福建省10种乡土野生绿化树种驯化及应用推广

通过对福建省乡土野生绿化树种调查,筛选出园林观赏价值高、经济效益好的福建山樱花、香港四照花等10种乡土野生绿化树种进行驯化栽培试验,总结出栽培配套技术和3年生各树种生长情况,投入产出比达1∶3~1∶13,获得显著社会、生态和经济效益,为园林规划和林业生产提供科学依据。     

鄂尔多斯主要绿化树种引种研究

通过对鄂尔多斯7种不同种源主要绿化树种胸径(地茎)、树高、冠幅、新生枝长的观测,以及多指标综合分析,以确定每一树种的最佳种源地。研究结果表明,乡土树种和在本地引种驯化多年的树种均表现为本地种源适应性最强,生长表现最好;外来引进树种表现为由自然条件较差地区向自然条件较好地区引进适应性较强,生长表现较好。建议鄂尔多斯市在以后的绿化过程中,要注重推广应用乡土树种和引种驯化多年的树种;而在引进外来树种时,要坚持从相应的种子区(亚区)或相邻的种子区(亚区),以及从自然条件低于鄂尔多斯市的地区选购。     

东莞大岭山村边自然次生林群落物种组成特征及其对区域物种库的贡献

对东莞大岭山村边自然次生林（俗称“风水林”）调查表明,群落组成种类复杂并富于热带性,1hm^2样地内共有维管束植物111种,隶属56科89属,其中以木本植物占绝对优势,有67种,占60．36％;群落中种子植物属为热带分布的共有74属,占总属数的92．5％。群落乔木可分三层,以越南山龙眼为主,其在各层的重要值分别为117．12％,129．44％和57．41％;灌木层以罗伞树和九节等为主;草本层植物以乔灌木小苗为主,草本植物仅沿阶草、海芋和半边旗等少数种类。群落木本植物的科、属、种对区域物种库的贡献率较大,分别为37．7％,25．6％和22．5％,以藤本植物的贡献率最高,接近50％,乔灌植物的贡献率也在20％左右．与鼎湖山季风常绿阔叶林比较．两者物种组成结构相似．但组成种娄仍有一定差距．     

Species Interactions in the Dynamics of Even- and Uneven-Aged Boreal Forests

Many boreal tree stands are neither clearly even-aged nor clearly uneven-aged. The stands may undergo a series of stages, during which an even-aged stand is transformed into two-storied mixed stand, and finally to multistoried or uneven-aged stand structure. The species composition often changes during the succession of stand stages. This study developed models for stand dynamics that can be used in different stand structures and species compositions. The model set consists of species-specific individual-tree diameter increment and survival models, and models for ingrowth. Separate models were developed for Scots pine, Norway spruce, and hardwood species. The models were used in a growth simulator, to give illustrative examples on species influences and stand dynamics. Methods to simulate residual variation around diameter increment and ingrowth models are also presented. The results suggest that mixed stands are more productive than one-species stands. Spruce in particular benefits from an admixture of other species. Mixed species improve diameter increment, decrease mortality, and increase ingrowth. Pine is a more beneficial admixture than birch. Simulations showed that uneven-aged management of spruce forests is sustainable and productive, and even-aged conifer stands growing on medium sites can be converted into uneven-aged mixed stands by a series of strong high thinnings.     

沙地人工模拟飞播对植物多样性的影响——以正蓝旗科技支撑项目区为例

从植物多样性恢复利用的角度来探讨治理流动沙地的有效途径和方法,对正蓝旗科技支撑示范区的人工模拟飞播植物群落进行了调查和分析,结果表明:项目实施区中的扁蓿豆、冷蒿、冰草等10种植物的重要值均大于对照区;二裂委陵菜、苔草、虫实等10种植物重要值均小于对照区;物种丰富度指数大于对照样地,Alatalo均匀度指数小于对照样地,而多样性指数明显大于对照样地;1年生草本植物种的重要值低于对照区,而多年生草本植物明显高于对照区。     

植物引种与外来物种入侵的探讨

生物入侵正在成为影响我国生态系统的重要因素之一。外来生物入侵的问题 ,越来越受到全社会的关注。本文主要分析了我国外来入侵植物的现状 ,如外来入侵植物的主要种类、对我国生态环境的危害、主要传入途径以及监控措施。     

Socio-economic determinants of smallholder plantation sizes in Ghana and options to encourage reforestation

Reforestation, particularly in the tropics, is of crucial importance for the environment as well as society. However, small planting areas and low participation of smallholder farmers in tree planting programmes often obstruct realisation of set planting area targets. In this regard, we interviewed smallholder farmers undertaking indigenous species reforestation in Oda Kotoamso community within the Wassa Amenfi West District in Western Region of Ghana with a pre-tested questionnaire to identify (1) key socio-economic factors that predict the size of plantations they establish, (2) options that could encourage tree planting among smallholder farmers, and (3) tree species planted by the smallholder farmers and their conservation status according to the IUCN Red List of Threatened Species. Key socio-economic factors were predicted with multiple regression models and ANOVA. Options were ranked on a five-point Likert scale and their differences were tested with the Mann–Whitney U test. Age and income of smallholders are the significant predictors of plantation sizes but farmers’ household size and gender were not significant. Age and income accounted for 77.1% and 22.9%, respectively, of the total variation described by our model (R?² = 38.4%). In order of importance, incentives (mean = 4.35, SD = 0.48), public nurseries (mean = 4.2, SD = 0.82) and agroforestry (mean = 4.06, SD = 0.56) were the options that could encourage reforestation, though incentives and public nurseries were not significantly different (p > 0.05). Almost half (9 of 19) of the tree species planted are categorised as Vulnerable species, which highlights the contribution of smallholder farmers to recovery of threatened tree species. Our findings suggest that sustainable provision of planting materials in incentivised and youth-based tree planting programmes could increase planting hectarage and conserve threatened tree species.     

北京地区主要树种理化性质研究及易燃性初步分析

森林燃烧所释放的热量、火种类、火行为等各种林火属性与树种易燃性密切相关,而树种的理化性质在一定程度上制约着易燃性,因此对树种理化性质和易燃性的研究是必要的。基于20种树种的实验分析,确定了可燃物热值、抽提物含量、灰分含量、含水量、密度的相关性,并建立相应的回归模型;基于树种理化性质的分析,比较了20种树种的易燃性,进行排序并划分等级。     

Edge effects on soil seed banks and understory vegetation in subtropical and tropical forests in Yunnan,SW China

Human-induced forest edges are common in many forest landscapes throughout the world. Forest management requires an understanding of their ecological consequences. This study addressed the responses of three ecological groups (non-forest species, secondary forest species and primary forest species) in edge soil seed banks and edge understory vegetation, and explored the relationship between the invasion of non-forest species in edge understory vegetation and the accumulation of their seeds in edge soil seed banks. The soil seed banks and understory vegetation were sampled along transects established at the edges of a continuous subtropical evergreen broad-leaved forest tract (Lithocarpus xylocarpus forest) bordering anthropogenic grasslands and three tropical seasonal rain forest fragments (Shorea wantianshuea forest) bordering fallows. Species composition in both soil seed banks and understory vegetation showed great difference among edge sites. In soil seed banks, the dominance (relative abundance and relative richness) of each ecological group did not change significantly along the edge to interior gradient. In understory vegetation, the invasion of non-forest species concentrated on the first several meters along the edge to interior gradient. The dominance of secondary forest species decreased with distance from the edge, while the dominance of primary forest species increased with distance from the edge. In forest edge zones, the invasion of a majority of non-forest species in understory vegetation lags behind the accumulation of their seeds in soil seed banks. Forest edges do not act as a good barrier for the penetration of non-forest species seeds. The lack of non-forest species in understory vegetation must then be due to conditions that are not appropriate for their establishment. Therefore, to prevent germination and survival of non-forest species further into the forest, management should focus on maintaining interior forest conditions.     

重庆市优良乡土树种综合评价与选择研究

在对重庆市的自然条件及社会经济状况分析的基础上,对实地调查和通过资料查阅确定的60种重庆市优良乡土树种进行了综合评价及选择。分别依据不同用途的树种制定不同的选择标准,确定出若干评价指标：对用材树种选定了速生性、丰产性、耐瘠性、抗寒性、抗旱性、抗病虫害能力、干材形质、材用价值等8个指标;对生物质能源树种选定了速生性、丰产性、耐瘠性、抗寒性、抗旱性、抗病虫害能力、多用途性、工业价值等8个指标;对景观树种选定了观叶、观花、观果、观树形、抗寒性、抗旱性、抗病虫害能力、抗污染性、吸硫能力、滞尘能力、降低噪音能力等11个指标。采用3分制并提出了每个指标的分级标准,运用层次分析法来确定各个指标的权重,根据各指标的分值和权重对60个目标树种进行了综合评价。主要结果与结论如下：（1）对20种用材树种进行综合评价的结果表明：鹅掌楸、香椿、桤木、檫木、毛桂、香樟为综合效益较高的用材树种,苦楝、川楝、厚朴、山杜英等树种次之。（2）按照20种生物质能源树种的综合评价值大小,建议选择杜仲、桤木、苦楝、刺槐、光皮树、山桐子等树种作为生物质能源林建设的主要树种。此外,灯台树、山苍子、文冠果、麻栎、栓皮栎等可以作为备选树种。（3）通过对20种景观树种的综合评价分析得出,深山含笑、四照花、珙桐、栾树、枫香、厚朴等是非常优异的观赏树种,可作为绿化骨干树种,枫杨、山桐子、红豆树、伯乐树等可作为绿化基调树种。