高山竹子新分类群

本文介绍了竹亚科高山竹子马箭竹、木里箭竹、雷波玉山竹三个新种 ,大姚箭竹新分布和西藏箭竹新异名     

王朗自然保护区引种竹笋：幼竹期异速生长规律的研究

本文以王朗1985年大熊猫主食竹类引种试验以来,筛选出的四个适应性最强的种:石棉玉山竹(Yushania lineolata)、青川箭竹(Fargesia rufa)、糙花箭竹(Fargesia scabrida)和冷箭竹(Bashania fangiana)及本地缺苞剪竹(Fargesia denudata)作材料,研究了各竹种当年生笋、一年生幼竹和二年生成竹的秆、枝、叶、箨和单株间以及与竹笋——幼竹期高径(D~2H)生长间的异速生长常数K的变化规律,建立了数学模型,并对竹笋到一年生幼竹的各器官(组分)的K值进行相关性研究,探讨在竹笋——幼竹期K值的变化规律。另外还根据笋秆K_s值与缺苞箭竹比较,确定各竹种竹笋——幼竹期的长短及进入稳定加固期的时间,评价各竹种的适应性能力。结果表明:笋期秆异速生长最显著的是糙花箭竹,顺次为石棉玉山竹、青川箭竹和冷箭竹。一年生幼竹器官异迷生长缺苞箭竹向多枝性发展,青川箭竹枝与秆之间生长近似于线性关系,秆、枝、叶和单株间成均衡性生长,而石棉玉山竹、糙花箭竹和冷箭竹则向少枝大秆型发展。单株生物量累积速度的主要因子是叶的生长,其次是秆、枝。二年生成竹的K值出现明显的变化,各竹种经竹笋——幼竹期进入稳定加固期的时间是不同的,石棉玉山竹和青川箭竹一般为1—2年,糙花箭竹和冷箭竹约为2—3年。竹笋——幼竹期K值因种和不同生长年龄而发生变化。笋期(秆、单株)生长速度与其笋成竹的秆、枝、叶和单株K值成负相关,但是笋期异速生长越快,则竹笋——幼竹期越长,进入稳定加固期较晚。对于可塑性强, 较为敏感的竹笋——幼竹来说,时间经历越长,对环境的生态适应能力将会变大。生产实践中,可用笋期秆异速生长常数K_s的大小来确定各竹种其笋进入幼竹和成年稳定后的适应能力及适应程度。表中的数字模型可用来预测生物量。     

王朗引种区大熊猫主食竹生长发育规律的研究

本文对平武王朗自然保护区引种大熊猫主食竹生育规律进行了研究。选用引种3年后生长表现较好的糙花箭竹(Fargesia scabrida)、石棉玉山竹(Yushania lineolata)、冷箭竹(Bashania fangina)、青川箭竹(F.rufa)4个竹种生长量与本地缺苞箭竹(F.denudata)作对比。通过生长过程的数学模拟和多元变量分析,探明5个竹种竹笋—幼竹期生长节律,日生长率及其生长与气象因子的关系。结果表明:引种的4个竹种都能适应本区条件,但在生长量上存在着种间差异。发笋多、生长快、长势好的竹种是糙花箭竹、冷箭竹和石棉玉山竹。影响竹种高生长的主要因素是热量因子。     

华西箭竹对卧龙亚高山森林不同演替阶段物种多样性与乔木更新的影响

比较阔叶林、针阔混交林与针叶林有竹与无竹环境下的物种多样性与更新状况.结果表明:华西箭竹的存在未改变森林演替过程中多样性的变化趋势,但降低了各阶段物种多样性,尤其对灌木层多样性的影响最为显著,对阔叶林物种的影响大于针叶林;与无竹环境相比,华西箭竹环境下林分各层物种丰富度都有所降低,灌木层的均匀度和多样性明显下降,但对草本层影响较小;阔叶林、针阔混交林与针叶林无竹环境乔木幼苗数量大于华西箭竹环境,箭竹环境光资源较差且枯落物较厚,不利于幼苗萌发与生长;糙皮桦幼苗及各径级树木在阔叶林无竹环境数量最多,而岷江冷杉在针叶林无竹环境最多,但在箭竹环境也有一定数量;华西箭竹的存在阻碍了糙皮桦的高生长,但对冷杉的影响较小,因此,华西箭竹的存在加速了糙皮桦的更新失败,同时也阻碍了冷杉的更新进程.总之,亚高山森林内华西箭竹的存在,降低了森林循环演替各阶段的物种丰富度与多样性,同时也不利于森林演替过程中乔木的更新.     

更新复壮技术对冷箭竹种群密度影响的初步研究

更新复壮技术对冷箭竹种群密度影响的初步研究周世强（中国保护大熊猫研究中心）大熊猫主要取食冷箭竹（Ｂａｓｈａｎｉａｆａｎｇｉａｎａ）的竹笋、竹茎、竹叶和少量竹枝［１］，因为笔者认为，评价老林复壮技术对冷箭竹繁殖生长的影响效果，应该采用试验区内冷箭竹的发...     

川滇竹类新植物

本文报道了产于四川、云南的竹类二新种及一新组合。新种是屏山方竹和翼箨箭竹;新组合是落叶箭竹。     

卧龙自然保护区竹类微量元素研究

用原子吸收分光光度法测定了四川卧龙自然保护区大熊猫主食竹种——冷箭竹(Bashania fangiana)、拐棍竹(Fargesia robusta)、华西箭竹(Fargesia nitide)、峨眉玉山竹(Yushania chungii)的叶、笋—幼竹、一年秆、二年秆、根、鞭共256例中的铜、锌、锰、铁、钙、镁、钾等七种元素含量。找到了微量元素含量与竹类、竹龄、竹株部位、竹的生长环境(海拔高度、季节)等的关系。     

中国植物志竹亚科新分类群

本文系《中国植物志》第九卷1分册(禾本科、竹亚科)中有关的新分类大群的预先报道。连同原型在内计包括2超族及5亚族,它们是(竹剌)竹超族、北美箭竹超族;又倭竹族(隶属于前一起族)下的刚竹亚族和倭竹亚族,北美箭竹族(隶属于后一超族)下的筱竹亚族、北美箭竹亚族和赤竹亚族。为了正式发表,使之能够在命名上成立,在本文中除中文叙述外,尚均给有拉丁文的形态描述。     

大熊猫除了竹子还吃什么？

<正>大熊猫每天进食大量竹子。冷箭竹、缺苞箭竹、青川箭竹、巴山木竹、峨热竹等是它们喜欢采食的竹种。但和其他采食竹子的动物不同,它们几乎只吃竹子,食谱的99%都是竹子。那么,它们食谱中其余的1%是什么？     

引种大熊猫主食竹种早期生物量的测定

本文对平武王朗自然保护区引种表现较好的4种大熊猫主食竹种冷箭竹(Bashaiafangiana)、糙花箭竹(Fargesia Scabrida)、青川箭竹(F·rufa)、石棉玉山竹(Yusania Iineolata)和本地缺苞箭竹(F.denudata)早期生物量及叶面积指标进行了测定.结果表明,在3种不同森林类型里的5个竹种中,平均单株生物量最高是冷箭竹为15.94g;平均亩产量最高是缺苞箭竹为7.27kg;不同年龄结构生物量为2年生高于1年生;各器官生物量分配比例:1年生杆大于2年生,2年生枝叶高于1年生.叶面积较大是糙花箭竹为52.28m~2/亩;叶面积指数1.8—5.4,处于中下水平.说明,引种竹生物产量低,而本地种产量高.立竹度小和发笋成竹力弱是影响早期生物产量不高的重要原因.在不同生态条件下,竹种的生物量及生物生产力既有类型、年龄与种间差异,又有不同程度的适应能力.     

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.