薄壳山核桃研究概况

通过对薄壳山核桃的经济性状、原产地及其分布、引种栽培、生物学特性、生态要求、品种类型、繁育研究等研究现状进行剖析,提出薄壳山核桃的发展趋势,以期能为我国林农在选择发展薄壳山核桃时提供一些参考。     

我国薄壳山核桃生产现状与产业化发展策略

在对薄壳山核桃在美国的栽培现状及我国引种栽培历史进行全面分析的基础上,针对目前薄壳山核桃产业发展过程中存在的主要问题,从充分利用现有种质资源,加快新品种培育进程;加强科学研究,提升薄壳山核桃产业发展的科技含量;实行定向培育,完善配套栽培技术体系等方面提出了我国薄壳山核桃产业发展的策略与建议,旨在为薄壳山核桃引种和开发利用提供理论依据。     

薄壳山核桃栽培技术要点探析

指出了随着我国国民生产总值的提高以及科学技术的进步,人民群众的生活水平不断提高,在饮食方面的追求也逐渐增高,人们越来越关注各类坚果的质量,对于坚果的需求量也越来越多,薄壳山核桃作为坚果中的一种,有非常高的营养价值,深受人民群众的喜爱。为了不断提高薄壳山核桃的产量,分析了薄壳山核桃的形态特征和生长习性,研究探讨了薄壳山核桃的栽培技术,以期提供参考。     

薄壳山核桃育种研究进展

总结了国内外薄壳山核桃的种质资源、育种目标、育种方法以及良种繁育等方面的研究情况,并针对薄壳山核桃在我国的育种研究现状提出建议。概述了薄壳山核桃的起源与分布、品种类型以及我国的发展状况;论述了果实品质优良、丰产稳产、花期相遇、挂果早、早熟性和抗病性六个方面的育种目标;分析了引种、选择育种、杂交育种和生物技术育种等育种方法;介绍了扦插繁殖、嫁接繁殖和组织培养等良种繁育技术。     

云南省薄壳山核桃种植现状及发展策略

在总结云南省薄壳山核桃种植历史的基础上,分析了薄壳山核桃发展的制约因素,并结合近年研究结果,提出了云南省薄壳山核桃发展的策略。     

薄壳山核桃造林地膜覆盖技术探讨

指出了薄壳山核桃属为胡桃科山核桃属落叶乔木,其坚果不饱和脂肪酸含量达60%左右,具有抗衰老、健肠胃等功用。同时薄壳山核桃的树干端直、根系发达,可用作庭荫树或者行道树,兼具绿化与果材双重作用。基于此,以薄壳山核桃造林中的地膜覆盖技术作为研究对象,以安徽望江县为造林地,进行了该地区薄壳山核桃造林中应用的地膜覆盖技术试验,提出了薄壳山核桃造林的经验及技术要点以供参考。     

薄壳山核桃实生苗侧根发生的育苗技术

薄壳山核桃具有深根性,不易发侧根的特点。为了促进侧根的发生,本文作者通过长期的生产实践,研究了一种促使薄壳山核桃实生苗侧根发生的方法。本文系统总结了促进薄壳山核桃实生苗侧根发生的技术流程,相关原理以及优点。为从事薄壳山核桃育苗栽培的果农提供技术支持。     

如何栽培美国薄壳山核桃

薄壳山核桃，又称美国薄壳山核桃、长山核桃，是国外引进的果材兼用的优良树种、坚果壳薄易剥，核仁肥厚，富含脂肪，味香甜，为干果食用及榨油的原料之一。薄壳山核桃原产美国，于1900年引入我国，目前引种范围较广，近年来引种地区逐渐增多。2011年，江苏省东海县石湖林场栽植了50亩薄壳山核桃，生长良好。     

薄壳山核桃研究概况及发展趋势

介绍薄壳山核桃优良的经济性状、在原产地美国的栽培情况以及在我国的引种栽培等情况,阐述其生物学特性、生态要求、品种类型及有性繁殖、无性繁殖、杂交育种等方面研究概况,指出薄壳山核桃的栽培与种植发展趋势．     

万亩薄壳山核桃在丽江落地生根

"随着今年12000亩薄壳山核桃在丽江成功落地生根,我们对10年内完成50万亩基地建设更加信心十足了。"丽江市市林业局种苗站站长李宏,说起薄壳山核桃这项新兴的特色生态产业的发展时如数家珍,激情昂扬。薄壳山核桃原称美国山核桃,为胡桃科、山核桃属落叶乔木。薄壳山核桃原产美国和墨西哥,是世界上重要的干果之一。薄壳山核桃为阳性树     

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.