太白山针叶林群落研究

本文对太白山针叶林植被进行了多元分析,结果表明,太白山针叶林可分为６个类型Ⅰ、巴山冷杉－秦岭小蘖群落;Ⅱ、巴山冷杉－四川忍冬群落;Ⅲ、巴山冷杉－糖茶蔗子－太白花楸群落;Ⅳ、巴山冷杉－太白杜鹃群落;     

陕西牛背梁国家自然保护区巴山冷杉群落结构特征研究

釆用样地法研究了牛背梁国家自然保护区巴山冷杉林群落结构特征,结果显示该保护区巴山冷杉林植物种类丰富,林中巴山冷杉在数量上占绝对优势,且分布均匀,而其他树种较少;巴山冷杉群落内灌木种类较少,分布极不均匀,多以团状或块状形式分布;巴山冷杉群落内草本植物稀少而苔藓发育较好,分布均匀。     

神农架顶峰的森林群落

<正> 在海拔二千四百--三千一百○五米之间的神农架顶峰地段,为巴山冷杉的自然分布区。巴山冷杉林,目前已达到稳定的顶极群落阶段,在它的形成过程中,基本上没有受到经济条件的影响,主要是在自然条件下完成的,故人称它为原生森林群落。依其生境和林木生长发育状况等因子的不同,可划分三个林型。即杜鹃--巴山冷杉林;箭竹--巴山冷杉林;黄杨木--巴山冷杉林。在巴山冷杉林分布的范围内,间有大片的箭竹丛     

色季拉山长鞭红景天种群生境特征

采用野外样地调查与监测法对西藏色季拉山长鞭红景天种群的生境进行研究分析发现,长鞭红景天种群生境主要为4个类型:急尖长苞冷杉林、方枝柏林、硬叶柳灌丛和鳞腺杜鹃灌丛。4个生境中,硬叶柳灌丛内有41种植物,急尖长苞冷杉林内有33种植物,方枝柏林内有29种植物,鳞腺杜鹃灌丛内仅有17种植物。不同生境群落中长鞭红景天种群数量特征各异,重要值排序为鳞腺杜鹃灌丛方枝柏林急尖长苞冷杉林硬叶柳灌丛。4个生境群落中月平均气温排序为急尖长苞冷杉林硬叶柳灌丛方枝柏林鳞腺杜鹃灌丛,平均湿度排序为鳞腺杜鹃灌丛方枝柏林硬叶柳灌丛急尖长苞冷杉林,光照强度排序是急尖长苞冷杉林硬叶柳灌丛鳞腺杜鹃灌丛方枝柏林。不同生境土壤温度排序为硬叶柳灌丛方枝柏林急尖长苞冷杉林鳞腺杜鹃灌丛,而土壤湿度排序为硬叶柳灌丛方枝柏林鳞腺杜鹃灌丛急尖长苞冷杉林。不同生境群落中空气温度、湿度、光照强度,土壤温度、湿度等存在较大差异,对长鞭红景天种群也有相应的影响,结合数据特征来看,鳞腺杜鹃灌丛是其最适生境。     

卧龙大熊猫栖息地植物群落多样性研究I．植物群落的基本特征

本文应用植物群落学理论分析了卧龙自然保护区野生大熊猫主要栖息地的植物种类组成、区系地理成分、优势树种以及生活型谱等特征。结果表明：卧龙大熊猫主要栖息于以铁杉、岷江冷杉、麦吊云杉、四川红杉、西南樱桃、华西枫杨、连香树、疏花械、川滇长尾械、水青树、领春木、红桦、糙皮桦等树种组成的落叶阔叶林、针阔混交林和亚高山暗针叶林内。栖息地群落中分布的常见种子植物有72科182属413种，其中裸子植物12种，双子叶植物362种，单子叶植物51种；且以松科、桦木科、械树科、杜鹃花科、忍冬科、蔷薇科、杨柳科、五加科、竹亚科、虎耳草科、菊科、毛莨科、荨麻科、禾本科等科植物构成优势组合，占组成植物总数的56％以上。从植物地理成分分析来看，无论是科分布型，还是属分布型，大熊猫栖息地植物都以温带分布类型为主，分别占47．2％和48．9％。植物群落生活型谱中以高位芽植物占优势，达54．96％，反映出大熊猫栖息地的植物群落具有温带落叶阔叶林和寒温带针叶林的特点。     

米仓山巴山水青冈群落结构特征及更新状况分析

巴山水青冈林在四川盆地北缘中山地带有保存比较完整的天然常绿、落叶阔叶混交林类型。以米仓山为重点,开展了对巴山水青冈群落结构特征及更新状况分析,结果表明:①巴山水青冈林林冠整齐,分层明显,有乔木层、灌木层、草本层和苔藓层;巴山水青冈为乔木主要优势树种。②在巴山水青冈天然林群落中,生长季节具有温热多湿的特征,群落高位芽植物分布最多,占了56.4%,其次为地面芽植物,占35.1%。③巴山水青冈林木胸径和年龄的分级均表现为中间高两头低的对称分布,林下巴山水青冈幼苗株数每hm2在2 800株以上,表现了群落结构稳定。     

大熊猫栖息地冷杉属植物群落与大熊猫分布的关系

冷杉属(Abies)物种组成的森林是我国特有的山地寒温性暗针叶林,在秦岭山系、岷山山系、邛崃山山系、大相岭山系、小相岭山系和凉山山系分布着以秦岭冷杉(Abies chensiensis)、巴山冷杉(A.f argesii)、岷江冷杉(A.faxoniana)、冷杉(A.fabri)、长苞冷杉(A.georgei)和川滇...     

白龙江沙滩林场高山林线主要森林群落结构与数量分布

高山林线是一种典型的生态交错带,是对气候反映最敏感的地区之一。通过对白龙江沙滩林场高山林线主要森林种群结构的研究,结果表明:(1)沙滩林场高山林线区域植被分布比较明显,随着海拔的升高,依次是乔木林、乔灌混交林、灌木林、高山草甸,最后是裸岩;群落垂直分层最上层以岷江冷杉为主,中层主要是杜鹃,下层以小灌木为主。(2)研究区主要以岷江冷杉和杜鹃为建群种,重要值分别是25.99%和27.73%,两者之和超过其他所有物种之和,相对优势度分别为39.39%和29.08%,两者之和占所有植物优势度的70%左右。(3)从群落的高度级分布的统计结果来看,高度级结构呈倒J型分布。高度级第Ⅰ级的植物株数最多,其中岷江冷杉幼苗占31.9%,杜鹃幼苗占28.6%。     

森林花草香型空气清新剂研制简报

天然冷杉精油具有杀菌消毒、驱杀害虫、香气馥郁等特性，据此，我们开发研制出了富含冷杉精油的森林花草香型空气清新剂，为开发冷杉精油在日化工业领域的应用提供了依据。１材料巴山冷杉精油；巴山冷杉水浸液（西北林学院巴山冷杉精油开发研究课题组提供）；杨梅油、薄荷...     

牛背梁自然保护区植物群落和针叶树小蠹虫群落物种多样性研究

对牛背梁自然保护区的山麓农田-侧柏群落(群落Ⅰ),油松-华山松-锐齿栎群落(群落Ⅱ),油松-华山松-栓皮栎群落(群落Ⅲ),油松-华山松-辽东栎群落(群落Ⅳ),巴山冷杉-落叶松群落(群落Ⅴ),红桦-牛皮桦-巴山冷杉群落(群落Ⅵ)6种类型群落的高等植物及其针叶树小蠹虫的多样性等进行研究.结果表明:在山麓灌丛群落至针阔混交林群落之间,物种多样性指数、群落均匀度指数和物种丰富度呈递增趋势;在中山针阔混交林群落与巴山冷杉和落叶松群落、红桦-牛皮桦-巴山冷杉群落之间,物种多样性指数、群落均匀度指数和物种丰富度呈下降趋势.从总体来看,森林植被的多样性程度高于灌丛和草甸,阔叶林则高于针叶林.群落优势度指数的变化规律则与之相反.不同森林群落类型中针叶树小蠹虫的多样性、均匀度和优势度研究结果表明:针叶树小蠹虫群落物种多样性指数和均匀度由高到低的排列顺序依次为:群落Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ、Ⅰ;针叶树小蠹虫群落优势度的变化趋势与之相反.不同类型的森林植物群落中,针叶树小蠹虫群落结构及多样性存在明显差异.生态环境复杂,植被丰富的中山针阔混交林群落中,针叶树小蠹虫多样性和均匀度指数均较大,但优势度指数低,小蠹虫大发生的几率较小.加强管理,促进森林生态系统的多样性和稳定性,对提高植物群落自身调控害虫种群数量具有重要意义.     

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.