“互联网+林业”的应用与展望

"互联网+林业"是"互联网+"的一个重要分支。通过分析我国"互联网+林业"的新形势,明确提出"互联网+林业"是现代信息化林业发展的新方向。阐述了"互联网+"下林业应用的新模式,同时对其面临的机遇和研究重点进行了初步探索。     

福建柏圃地育苗技术

福建柏是我国南方特产的优良装饰用材树种,适应性强,生长快,根系有多种菌根菌,能培肥改良土壤,可多代连栽.其树形优美,枯枝落叶少,可用于园林绿化.由于野生资源少,被列为国家二级重点保护植物,是国家"九五"、"十五"科技攻关重点研究与推广造林的珍贵乡土树种.我们对福建柏育苗进行了研究,现将其技术总结如下.     

我国麻疯树地理种源及分布区考证

经过详细地调查研究证明,我国滇、川、黔三省的热带和亚热带干热河谷区存在大量麻疯树天然群落和野生种群,并对其进行了植物形态学、生长生物学、群落生态学、种群生态学和分布区学的全面研究和再认识,提供了丰富和确切的观察结果。在上述研究基础上,进一步提出了"雨林型"麻疯树地理种源和"萨王纳型"麻疯树地理种源的新概念,为我国麻疯树产业化种植及分区规划提供了依据。金沙江干热河谷"萨王纳型"麻疯树地理种源的存在和出现展示着该物种在纬度极限和海拔极限条件下的生存能力,充分证明其泛热带分布和广泛分布于热带亚洲、热带非洲和热带大洋洲的事实,为麻疯树植物区系地理学研究提供了佐证。     

不同构树品种药用化学成分含量比较和综合评价

为了研究比较不同构树品种Broussonetia papyrifera中化学成分含量的变化,研究以1 a生的"白皮"构树、"红皮"构树、"杂交"构树和对照构树为试验材料,分别提取并测定了其叶片、茎、根中牡荆素、异牡荆苷、大波斯菊苷、木犀草苷、木犀草素、芹菜素、总多糖、总多酚、总黄酮的含量,并对其进行比较分析和综合评价。结果表明,构树叶的药用价值大于根部和茎部,四个构树品种中"红皮"构树的药用价值较高。     

浅论中州盆景艺术的发展与美学内涵

本文阐述了中州盆景悠久的历史。在其制作空前繁荣、队伍日益扩大、研究水平不断提高的现状基础上,进一步论述了中州盆景艺术的美学内涵应突出表现在追求"源于自然"、突出"主次分明"、形态"疏密相间"以增强作品的表现力。     

“金叶沙地柏”培育技术

"金叶沙地柏"由沙地柏的芽变侧枝发育而来,其枝条斜生,树冠外层叶色金黄,树体外观呈金黄色,具有较高的观赏价值。经11年的繁育与研究,发现其性状稳定。文章详述了其特性,并从扦插、苗期管理等方面介绍了其繁育技术。     

矾根"草莓漩涡"对高温胁迫的生长及生理响应

以矾根"草莓漩涡"为试验材料,研究了其对高温环境条件的耐受能力。研究结果显示,高温胁迫限制了矾根"草莓漩涡"株高、冠幅的增长和生物量的积累效率。高温环境条件下,草莓漩涡可溶性糖含量、可溶性蛋白含量呈现出先增高后降低现象,O■、H_2O_2和MDA含量持续增高,SOD、CAT和POD活性快速增高后缓慢降低。结论:一定时间和温度范围的高温胁迫会导致矾根"草莓漩涡"生长受限,但不会造成其死亡。矾根"草莓漩涡"对重庆夏季高温具有一定的耐受性,能够通过自身生长、生理调节来应对高温环境。     

风景园林视野下库哈斯的城市公共空间设计思想解读

面对当代城市的不确定性、流动性和高密度性,库哈斯提出了一种适应现代大都市特征的理论——"拥塞的文化"。通过研究都市的大众文化需求,他将建筑与城市设计理论衍生至城市公共空间,从而达到将城市公共空间转化为"社会凝聚器"的战略目的,其设计思想在大都会建筑事务所(OMA)城市公共空间项目中不断发展,并对景观都市主义产生了重要影响。国内外现有关于库哈斯理论的研究主要集中在建筑领域,在其城市公共空间思想的研究上近乎空缺。从风景园林视野研究库哈斯的城市公共空间思想,通过梳理其生平经历、理论著作、实践作品,深入解读库哈斯的城市公共空间设计思想、策略及表征,为国内高密度城市风景园林建设提供一定跨界理论参考。     

我国珊瑚礁生态系统研究现状及发展趋势

指出了珊瑚礁生态系统是以珊瑚礁生物为中心和生活在珊瑚礁环境里无数生物构成的一个有机整体,也被称为"海洋之肺"和"热带海洋中的绿洲"。它是生物多样性最丰富的海洋生态系统,在海洋中扮演着重要角色,但同时也是脆弱的,一旦遭到破坏在短时间内将很难恢复。综述了珊瑚礁生态系统在生态环境、修复研究和保护方面的研究现状,并结合实际问题展望了其发展趋势。     

国内旅游危机事件研究述评

通过对中国知网"旅游危机"相关的中文文献进行检索统计,发现知网关于国内此类研究的收录源于2003年,并对其每年的文献数目、研究机构、作者、关键词进行统计分析,发现国内关于"旅游危机"的研究分为三个阶段,分别为:2003～2007年、2008～2011年、2012～2019年。对这三个阶段论文的特点及内容进行了深入的探讨,总结了出未来相关研究的发展趋势。     

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.