湖北京山对节白蜡自然保护区种子植物区系研究

通过对京山对节白蜡自然保护区进行野外调查及文献检索,分析其植物物种组成和区系地理成分.结果显示：保护区共有种子植物133科496属939种.区系组成中,在科的层次上,Compositae为保护区内含植物种类数最多的科;在属的层次上,Polygonum为含植物种数最多的属,种的层次上,Fraxinus hupehensis为保护区内绝对优势植物,分布范围极其广泛,从保护区的最低海拔到最高海拔均有分布,并多区域形成群落.初步探讨了该地区植物区系的性质：区系成分具有复杂性和多样性,拥有中国种子植物分布区类型科级水平的12个类型,属级水平的15个类型,各类热带成分共164属,占总属数的37.44％;各类温带分布类型（不包括中国特有分布）共264属,占总属数的60.27％,植物区系偏重于温带性质,具有亚热带向温带过渡的特点.保护区内特有性较突出,有中国特有分布有10属,特别是大洪山南麓区域特有种—Fraxinus hupehensis分布范围极其狭窄,仅分布于京山县和钟祥市接壤的大洪山余脉伸入部分形成的低山高丘类型地区.     

海南岛吊罗山地区珍稀濒危植物区系研究

吊罗山地区有"红皮书"保护植物34种,"国家重点"保护植物33种,隶属8个属分布区类型、4个种分布区类型。以热带成分的属占优势,热带亚洲分布类型所占的比例最大;特有成分较突出,特有种隶属于3个分布类型,以华南分布为中心。吊罗山与五指山、尖峰岭的种、属相似程度高,其中与五指山的相似度最大。吊罗山珍稀濒危植物可用作园林、药用、木材、农业资源植物,多分布在低、中海拔的湿润密林或沟谷林中,对森林依赖性很强,要采取相关措施对这些物种及其生境进行保护。     

藏东南兰科植物多样性及其沿海拔梯度的分布格局

藏东南是喜马拉雅地区生物多样性热点地区的重要组成单元,拥有丰富的野生动植物资源。兰科植物是被子植物的第二大科,但对该科植物在藏东南地区的物种数量及分布规律仍然缺乏系统的研究。本研究通过野外调查并结合文献资料,确定了藏东南地区的兰科植物种类及其生活型;并将研究区域按500 m划分为9个海拔梯度,结合系统发育分析了兰科植物垂直分布格局。结果共发现野生兰科植物89属336种(变种),其中地生兰187种、附生兰136种、菌类寄生兰13种。整体来看,兰科植物主要集中分布在1 500～3 500 m海拔段,尤其在海拔2 000～2 500 m分布最多。研究结果表明,藏东南兰科植物呈"中间高度膨胀型"海拔分布趋势,其生活型也有同样的趋势。相邻海拔梯度的兰科植物相似性系数较高,随着海拔差距增大,相似性系数也随之降低。兰科植物区系成分中热带亚洲成分最高(32.8%),其次为中国-喜马拉雅成分(26.2%)和中国特有成分(15.3%)占绝对优势,3者之和占总种数的74.3%。     

卧龙国家级自然保护区马先蒿属植物多样性及保护研究

通过野外调查、标本整理以及查阅文献等方法,对四川卧龙国家级自然保护区马先蒿属植物种类、分布、现状及保护利用进行了研究.结果表明:辖区共有42种马先蒿属植物(含变种及亚种),分属10群27系,其中30种为中国特有,特有性高达71.43％;马先蒿属植物在辖区主要分布在海拔2500?m以上区域(39种、92.86％),其中海...     

岷江上游杓兰属植物资源及其海拔分布格局研究

以岷江上游杓兰属植物为研究对象,通过实测法、样线结合样方法,调查研究杓兰属植物的种类及其海拔分布格局,结果表明:(1)岷江上游分布有17种杓兰属植物,分别占全国和全省杓兰属植物资源的47.22％、73.91％.该区的杓兰属植物资源特有性较高,紫点杓兰、对叶杓兰、离萼杓兰、山西杓兰和西藏杓兰为世界广布种,其他12种杓兰均...     

诏安县乌山国家森林公园野生兰科植物多样性研究

对诏安县乌山国家森林公园内的野生兰科植物进行调查,共记录到32属51种。调查新发现属种有绒兰属白锦绒兰、钟兰属钟兰等。通过对不同海拔梯度兰科植物多样性分析表明,乌山山腰部400～800 m海拔较湿润的小气候环境是野生兰科植物分布丰富度较高的主要因素;乌山野生兰科植物热带成分的属占比最大,热带性质明显;与毗邻地区野生兰科植物分布对比,丰富度较高。     

佛坪自然保护区珍稀濒危保护植物及分布

佛坪自然保护区属陕西省珍稀濒危保护植物分布较集中的地区之一。根据多年来的调查,该区共有国家珍稀濒危保护植物23种,占陕西省珍稀濒危保护植物总数的53.49%。其中,二类保护植物10种,三类保护植物13种。除银杏为半野生外,其余均为野生种。佛坪自然保护区珍稀濒危保护植物分布情况见下表。从表可以看出,这些植物垂直分布在海拔2000m 以下的落叶阔叶和针阔叶混交林内的有19种,占保护区珍稀濒危保护植物总数的82.6%;太白红杉、独叶草,星叶草和桃儿七等4种分布于针叶林带。上述植物以     

湖南桂东三台山种子植物区系研究

采用线路调查、样地调查和查阅相关资料文献相结合的方法,对湖南省桂东县三台山种子植物区系进行研究。结果表明：三台山共有维管束植物183科、688属、1307种,其中种子植物162科、656属、1233种,占湖南全省种子植物种数的19.81％。除栽培或逸生植物外,该地共有野生种子植物149科585属1095种。野生种子植物中科有10个分布型,属有14个分布型,种有14个分布型,分布型组成较复杂;除世界广布型（1分布型）外,热带成分（2～7型）科、属、种占总科、属、种数的比例分别是44.96％、41.71％、23.38％;温带成分（8-14型）科、属、种的比例分别为25.50％、47.51％、39.90％;中国特有分布型（15分布型）大部分可归类为温带性质;种子植物区系中有10个中国特有属和373种中国特有种,这些属和种与华东、华中、华南等地区联系广泛;种子植物区系具有中亚热带向南亚热带过渡的特点,其中华南特有分布植物,尤其南岭山地特有分布的植物种类较多。     

中国西南地区濒危植物的区系地理研究

根据《中国植物红皮书》第一册，中国西南地区共有濒危植物(除去稀有和渐危植物)28科，41属，52种。文章对这些植物的生活型、分布区类型、地理分布和植物区系分区的特征进行了分析。主要结果表明，从属的分布来看，西南地区37属濒危种子植物中，热带分布型属有16属，占种子植物属的43．3％，温带分布型属有19属，占51．4％，中国特有分布型属只有2属，其中1属为西南地区有属，说明属的特有分布现象不明显；从西南地区52种濒危植物的水平分布来看，有33种为西南地区特有种，占63．5％，说明种的特有分布现象明显；西南地区跨越了我国仅有的两大植物区，5个地区，植物区系成分复杂。     

德宏州棕榈科植物资源及其分布特征研究

通过对德宏州棕榈科植物进行野外重点线路调查,统计其分布区类型,采用植物区系学的研究方法对其地理区系特征进行分析,结果表明,德宏州是云南及中国棕榈科植物资源最为丰富的地区之一。该区共有棕榈科植物10属36种及变种(不含栽培种),其中省藤属13种,蛇皮果属、刺葵属为单种属。棕榈科中中国特有分布8种,其中,云南特有分布5种。以盈江(中缅)边境地区海拔240～1 000 m为德宏棕榈的密集分布区,海拔2 000 m为分布上限。德宏棕榈植物的种类以热带亚洲分布类型为优势,具有明显的印度-马来成分特点,与缅甸(13种共有种)及滇南(西双版纳)热带有着非常密切的联系,同时该区具有明显的热带边缘分布特征。     

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

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.