苏州市穹窿山芭蓬自然保护区植物资源的研究

苏州市究窿山柔蓬自然保护区有一维管植物２１６种（含变种），具有中国种子植物属的地理分布类型全部１５种中的１３种，缺少地中海、亚至中亚分布和中亚分布类型。本区共有药用植物药１５１种，观花植物７１种，以白、红或紫色为主，观果植物约３ 上，以红色为主，观叶植物有２０种，藤蔓类植物１４种，行道树和庭园树种有１６种。建议本区发展生态旅游以及合理开发利用观赏植物资源。     

石羊河下游干旱荒漠区盐爪爪群落植物分布区类型

通过对石羊河下游干旱荒漠区盐爪爪群落调查,结果表明:本区域盐爪爪属植物种类有盐爪爪、细枝盐爪爪、圆叶盐爪爪、黄毛头;其群落伴生种有11科19属28种植物,主要由多年生盐生草本和盐生灌木组成;群落植物科的分布区类型以世界分布区类型为主,属的分布区类型以地中海区、西亚至中亚分布及其变型和世界分布成分为主。     

河南嵩顶国家森林公园植物多样性调查研究

河南嵩顶国家森林公园位于河南省嵩山北麓,调查发现本区维管植物共计155科、656属、1601种。根据地理分布格局,分为15个类型,其中热带分布类型占25.00%,温带分布类型占48.02%。本区植物具有以温带性质为主兼有热带成分的南北过渡性特征,植物类群之间亲缘关系复杂多样,植物区系地理成分多样。本区的自然地理环境对植被的分布与繁殖具有重要作用,本区植物种类丰富且具有较高的代表性和多样性,在河南植物分布中占据重要地位,具有较高的学术、科研意义和保护价值。     

克拉玛依农业综合开发区外围荒漠种子植物区系研究

调查研究表明:克拉玛依农业综合开发区外围荒漠有种子植物27科90属119种。对该区种子植物区系进行了统计分析,结果表明:①科属构成简单,单种科、少种科和单种属、寡种属占比例大;②科属的地理成分中,温带成分占优势;③属的区系成分有7个分布型和6个变型,其中地中海、西亚至中亚分布型占优势,包含属数占本区系总属数的35.56%,占新疆同分布型种子植物总属数的22.54%。表明本区属于中亚荒漠。     

河西走廊沙漠人工林群落结构特征

在实地踏查的基础上,设置典型调查样地,调查分析了河西走廊沙漠人工林植物的物种组成和群落类型,描述了物种的地理成分、区系特征和生活型谱。结果表明:1)河西走廊沙漠人工林共有种子植物48种,分属14科41属,物种组成以藜科、禾本科和菊科等植物为主。2)群落植物的科、属、种区系成分类型多样,温带成分占优势,其次为地中海区-西亚-中亚分布成分,具有温带荒漠性和古老性;科的分布型有3个分布型2个亚型,属和种的地理成分可归入8个分布型4个亚型;生活型谱以1年生植物(37.5%)为主,地下芽植物(27.1%)次之。3)研究区植被可划分为3个典型群落:梭梭群落、胡杨群落和红柳群落。梭梭群落是主要建群种,分布面积广、物种数较多,优势种梭梭的重要值在0.34~0.73。胡杨群落和红柳群落分布面积少,群落盖度较低,植被稀疏。     

民勤荒漠植被特征及其适应特征初步研究

民勤荒漠区植物种类稀少,自然植被以沙旱生灌木、半灌木和草本为主,属于典型的荒漠植被类型;从植物区系分布看,以地中海-中亚分布成分为主,北温带分布成分、亚洲温带分布成分、中亚成分及旧大陆温带分布成分种类稀少;优势种、建群种单一;植被不稳定,植被盖度受当年降水情况影响较大;即使在降水条件好的年份,在人为活动影响少的地段的植被盖度最大只有45%;植物萌动,展叶开始时间较迟;植物的物候期受当年降水量和降水季节影响不大;多数植物靠种子繁殖,自然繁殖受当年降水量、降水季节和土壤条件影响大;种子自然繁殖一般出现在低缓的流动、半固定沙丘和平沙地上;流动和半固定沙丘(沙地)植被受年度降水量大小的波动性大。     

景宁望东垟、大仰湖保护区湿地植物调查及分析

对望东垟高山湿地自然保护区、大仰湖湿地群自然保护区的湿地植物资源进行调查,共发现湿地维管植物330种,隶属于82科200属,其中蕨类植物11科16属18种,种子植物71科184属312种。本区溪源湿地植物属的地理成分主要为北温带分布、泛热带分布、东亚分布和世界分布,这4种类型占了总属数的75.9%。热带性质属(类型2—7)的有58个,占36.9%(不含世界分布属),温带性质(类型8—15)的有99属,占63.1%。     

浙南的细柄蕈树林

本文讨论的细柄蕈树(Altingia gracilipes)林,分布于浙江南部地区,位于我国中亚热带东部,是该森林类型分布区的北缘。 据调查8个样地共5600m~2群落种类组成的统计,共含维管束植物52科,94届,145种,其中单型属占74.5％、比例很高;森林植物区系以热带分布的成分为主,占木本植物属的66.7％。表明该群落是属于中亚热带南部亚地带一个典型的常绿阔叶林类型。     

湖南高望界自然保护区维管束植物区系研究

高望界自然保护区地处武陵山脉南坡中段,隶属华中植物区。该地区物种丰富,已查清维管束植物204科846属1 883种,其中蕨类植物37科83属201种,裸子植物7科12属16种,被子植物160科751属1 666种;区系成分复杂,种子植物科级分布型可划分为10个分布型11个亚型,属级可划分为15个分布型20个亚型;特有成分多样,共有2个中国特有科25个中国特有属,众多中国特有种;区系起源古老,成分以中亚热带为主,过渡性特征显著;珍稀植物富集,有国家级重点保护野生植物74种(包括36种兰科植物)和湖南省地方重点保护野生植物25种。     

滇东北珙桐群落结构特征研究

在对滇东北9个样地总面积4500m^2珙桐群落进行野外调查的基础上,重点分析该地区珙桐群落的物种构成、区系成分、结构特征、群落相似性及珙桐更新状况．结果表明：①该地区珙桐群落植物种类十分丰富,共有蕨类植物7科10属16种,被子植物63科110属171种,且古老性、特有性强;②群落被子植物的区系构成中以温带分布型属为主,约占57．27％,缺乏温带亚洲分布,中亚分布和地中海区、西亚至中亚分布3种类型;③与四川省都江堰、卧龙和甘肃省文县等地珙桐群落植物区系构成基本相似,但温带成分略为减少,热带成分相对较多;④群落垂直结构明显,珙桐与各散生竹类构成独特的乔、竹、草结构,依群落中灌木层优势竹种不同而划分为3个群丛;⑤珙桐径级分布呈现出稳定增长的金字塔型,表明该地区珙桐种群能保持较长时期稳定,但珙桐更新种群以萌枝为主,极少见实生苗,表现出种群衰退迹象,而且群落更新层中有大量其他树种幼苗,若珙桐遭到破坏,它们将有可能取代珙桐的优势地位．     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.