广西珍贵树种人工林发展前景探讨

简述广西珍贵树种发展现状,分析广西珍贵树种发展潜力,并提出该地区发展珍贵树种中应注意的问题,旨在为珍贵树种在广西大力推广提供理论参考。     

融水县珍贵树种发展现状与培育途径

融水县为广西林业大县,山地面积大,森林资源丰富,不乏珍贵物种,发展珍贵树种自然条件优越。文章分析了融水县珍贵树种人工培育利用现状和存在的问题,并提出人工培育发展的途径。     

论我国珍贵用材树种资源的培育(续)

珍贵用材树种资源是我国重要的战略资源。文章探讨了珍贵用材树种的定义,及开展珍贵用材树种资源培育工作的意义和面临的问题,并提出了相应的政策措施和技术路线。加快珍贵树种的培育,除采取集约经营、定向改培、适当加大初植密度、加强抚育管理等技术措施外,要考虑与现有的林业重点工程相结合,与林下种养殖业相结合,与城市绿化相结合。     

论我国珍贵用材树种资源的培育

珍贵用材树种资源是我国重要的战略资源。文章探讨了珍贵用材树种的定义,及开展珍贵用材树种资源培育工作的意义和面临的问题,并提出了相应的政策措施和技术路线。加快珍贵树种的培育除采取集约经营、定向改培、适当加大初植密度、加强抚育管理等技术措施外,要考虑与现有的林业重点工程相结合,与林下种养殖业相结合,城市绿化相结合。     

桢楠容器育苗

桢楠（Phoebe zhennan）为樟科楠木属植物，属亚热带常绿阔叶高大乔木，是我国二级保护树种和著名的珍贵用材树种，是优良的绿化观赏树种。为了保护和发展桢楠这一珍贵树种，2008年4月至2009年3月我们进行了桢楠容器育苗试验。     

桢楠容器育苗

桢楠（Phoebe zhennan）为樟科楠木属植物，属亚热带常绿阔叶高大乔木，是我国二级保护树种和著名的珍贵用材树种，是优良的绿化观赏树种。为了保护和发展桢楠这一珍贵树种，2008年4月至2009年3月我们进行了桢楠容器育苗试验。     

发展优良珍贵树种 开创可持续高效益林业发展新局面

2006年11月21日至22日，自治区林业局在凭祥市召开全区优良珍贵树种造林暨今冬明春造林备耕动员会。会议的主要内容是：总结交流我区各地发展优良珍贵树种的基本情况、做法和经验，动员和部署各地加快优良珍贵树种的造林步伐，努力提高全区速生丰产用材林质量，确保2007年植树造林任务圆满完成。     

顶果木嫁接育苗技术

介绍了广西珍贵乡土树种顶果木优良苗木嫁接繁育的过程。包括嫁接前的砧木苗培育,接穗的选择,嫁接方法,以及嫁接后的嫁接苗管理等工作。     

蓄宝于山 藏富于民——浙江省扎实推进珍贵树种资源培育工作

浙江省“七山一水两分田”，具有发展珍贵树种的良好条件，是全国珍贵树种种源丰富、分布较集中的省份之。近年来，全省围绕“蓄宝于山，藏富于民”总体目标，坚持规模发展与分散培育相结合、人工造林与改造培育相结合，扎实推进珍贵树种资源培育工作。     

广西乡土阔叶树种遗传改良策略的探讨

广西乡土阔叶树资源十分丰富，其中不乏材性优良且速生丰产的树种，但由于对乡土阔叶树遗传改良重要性的认识不足，致使乡土阔叶树遗传改良步伐滞后。乡土阔叶树遗传改良以保护现有珍贵优良树种种质资源为基础，根据不同树种遗传改良的基础，循序渐进：先建立母树林满足当前生产需要；然后选择表型优良的种源、家系、单株，通过无性繁殖方式，边测定边利用，逐渐建立不同世代的种子园，最终实现乡土闻叶树种良种在生产中普遍应用。     

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。     

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。     

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。     

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。     

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.