吊丝单竹、云南甜竹、大头典竹出笋规律调查与分析

通过对吊丝单竹、云南甜竹、大头典竹在相同抚育措施下出笋规律调查,结果表明:吊丝单竹出笋早,出笋量大,平均达37.05支/丛,但出笋总重量低,平均仅25.25kg/丛,云南甜竹、大头典竹出笋迟,但云南甜竹的笋总产量最高,达42.2kg/丛,大头典竹出笋产量仅次,达40.1kg/丛。从方差分析上看,吊丝单竹与云南甜竹、大头典竹间存在1%极显著水平。从出笋的月规律变化上看,7月下旬和8月中旬均是3种竹子出笋高峰期,而7月中旬和8月上旬均出现出笋低谷期,8月中旬过后均出现出笋逐渐减少趋势,吊丝单竹、大头典竹9月下旬产笋仅零星出现,云南甜竹出笋则在9月下旬仍达到一个小高潮,而后出笋逐渐停止。     

吊丝单竹、云南甜竹、大头典竹出笋规律研究

对吊丝单竹、云南甜竹、大头典竹在相同抚育措施下出笋规律进行调查，结果表明：吊丝单竹出笋早、数量多，平均达37．05支／丛，但出笋总重量低，平均仅25．25／丛，云南甜竹、大头典竹出笋迟，但云南甜竹的笋总产量最高，达42．2／丛，大头典竹出笋产量次之，达40．1／丛。方差分析表明，吊丝单竹与云南甜竹、大头典竹间存在1％极显著水平。从出笋的月规律变化上看，7月下旬和8月中旬均是3种竹子出笋高峰期，而7月中旬和8月上旬均出现出笋低谷期，8月中旬过后均出现出笋逐渐减少趋势，吊丝单竹、大头典竹9月下旬产笋仅零星出现，云南甜竹出笋则在9月下旬仍达到一个小高潮，而后出笋逐渐停止。     

云南甜竹材性分析及开发利用价值初步评价

对云南甜竹化学成分、纤维形态、物理力学性质进行了测定,并在此基础上初步讨论了云南甜竹的开发利用价值。研究结果表明:云南甜竹化学组成、纤维形态、物理力学性质3个方面的性能指标满足制浆造纸、建筑材料、人造板材等工业对原料的要求,属较好的植物纤维原料,是一种具有较高开发利用价值的大型丛生竹种。     

云南甜竹在山区的引种试验

云南甜竹在山区的引种试验云南甜竹（ＰｅｎｄｒｏｃａｌａｍｕｓＹｕｎｎａｎｅｎｓｉｓｓｐ．ｎｏｒ．）是禾本科竹属，原产于云南西双版纳，早在１９６２年由华南植物园首先从云南省引种。广宁县林科所于１９８５年春从华南植物园引种云南甜竹苗１０株，经过１０多年...     

云南珍稀濒危竹类植物资源现状及保护对策

云南是中国竹类植物分布最丰富的地区,原始属种高度集中,生态类型齐全,全省分布广泛,属种种类丰富,其中53种为珍稀濒危竹种。文章介绍了云南珍稀濒危竹类植物的资源状况和保护现状,提出了保护云南珍稀濒危竹类植物的建议。文章认为应将云南分布面积在2 000 hm²以下的竹种纳入极小种群植物保护之列,并构建极小种群野生植物的种群生态学和保护生物学理论体系;同时保存和扩繁云南竹类极小天然种群,缓解濒危态势。     

云南4种典型热带丛生竹的种源分化

以典型的自然或栽培种群为研究对象,全面调查和分析了云南4种典型热带丛生竹——巨龙竹、龙竹、云南甜龙竹和黄竹种质资源及其遗传分化背景,并结合种群平均秆径和平均秆质量,初步评价了以种群为代表的各个竹种的种源分化状况。结果显示:4个竹种种群间的平均秆径和平均秆质量等主要营林指标差异显著;巨龙竹、龙竹、云南甜龙竹种群间存在着较高水平的遗传分化,其遗传分化系数(Gst)均大于0.83;而黄竹种群间也存在一定水平的遗传分化(Gst=0.252 4)。研究结果为筛选巨龙竹等4个竹种的优良种源提供了理论依据。     

云南甜竹包枝育苗技术与应用

甜竹原产于云南西双版纳,是当今发展“三高”林业的笋材两用新品种。该竹生长快、产量高,每公顷产竹材４５～７５万ｋｇ,是一较好的造纸原料;笋肉纤维细嫩,甘甜爽脆,是优南的保健食品,每公顷产鲜笋一般３０万ｋｇ,最高达４５万ｋｇ。云南甜竹种苗有较强的...     

黄甜竹引种研究通过了技术鉴定

由浙江省林科所进行的黄甜竹引种研究,于1990年5月18日由省林业厅主持通过了技术鉴定。到会专家、学者认为,黄甜竹原系福建野生竹,经浙江省林科所引种驯化,已成为我省可推广的笋材用竹种。黄甜竹具     

优良丛生笋用竹及杂种竹竹笋品质评价的研究

该文报道对同一栽培条件下的10种优良丛生笋用竹及4种杂种竹竹笋品质评价的研究结果.通过对各种竹笋的鲜食品质、加工性能及营养成份含量的综合评价,评选出三类优良竹种:第一类为优良鲜食型笋用竹种,包括版纳甜竹、云南甜竹、麻版1号竹,其鲜笋鲜食品质最好,营养成分含量较高,笋期长,产量高,但加工成干笋色泽欠佳;第二类为优良加工型笋用竹种,包括麻竹、毛麻1号竹、毛笋竹,其竹笋加工成干笋色泽最佳,笋体大,易加工,产量高,但鲜食品质较差,营养成分含量一般或较差;第三类为鲜食和加工兼用的优良竹种,包括撑篙竹、大头典竹、绿竹、吊丝竹、吊麻5号竹、撑麻7号竹,其竹笋鲜食品质及加工性状均较好,营养成分含量一般或较好,这些竹种的竹材材质较好,生长适应性较强、较抗寒,作为笋材两用竹在粤北以北的地区推广种植潜力大.     

云南优良甜龙竹种质资源及其保护策略

甜龙竹是大型优良笋材两用丛生竹种,鲜笋品质优良,是云南省重点发展的笋用竹种。甜龙竹天然种群因缺乏科学经营管护,种群退化较为严重,亟需对其种质资源和天然种群进行研究与保护。本文从种质资源现状、生物学特性、竹笋营养成分、培育技术以及种质资源保护策略等方面进行了综合分析。     

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.