油桐丰产栽培综合技术的研究

油桐是我国的特产。我省陕南山区有25个市、县种植油桐,栽培历史悠久,栽培面积较大,是全国主要产区之一,1988年栽培面积达9.6ha,年产桐油569万kg,油桐产区桐油收入约占林业总收入的20％,白河等主产县桐油年产值占林业总产值的50％以上,长期以来陕南山区的桐油还是沿用传统的生产方式,栽培品种混杂,良莠不齐,栽培技术落后,单位面积产量低,平均亩产桐油仅3.9kg,只是全国亩产桐油7kg的55％。为了改变陕南山区油桐低产的面貌,我们自1986年～1990年五年间研究出一套油桐丰产栽培综合技术,应用于生产,使产量有了大幅度提高。     

陕南山区油桐丰产栽培技术推广报告

陕南山区有25个市、县种植油桐,其栽培历史悠久,栽培面积较大,是全国主要产区之一。据统计,1988年栽培面积达150.24万亩,年产桐油568.96万kg。油桐产区县桐油收入占林业总收入的19.89％,白河等主产县桐油年产值占林业总产值的50％以上。长期以来陕南山区的油桐生产还是沿用传统的     

油桐林地不同土壤管理与生产性能

油桶产量的高低,不仅受本身遗传品质的控制,同时受生境条件的制约,而这种生境条件又受人为的生产活动所左右。土壤是油桐生长的基础,不同的土壤管理关系到油桐寿命长短,产量高低,因此,加强对桐林的土壤管理,是油桐生产中一项极其重要的技术措施。研究和了解不同土壤管理与油桐生长结实的关系,对制定桐林土壤管理技术措施,实现油桐高产稳     

中国油桐林地土壤类型的研究

土壤是油桐生长所需要的重要生态因素之一,加强油桐林地的土壤管理,提高土壤肥力,是油桐丰产栽培的重要技术措施。因此,必须加强对油桐林地土壤条件的研究,为科学地进行土壤管理提供理论依据。然而到目前为止,对油桐林地土壤研究的不多,从全国范围内研究油桐林地土壤类型的更是未见报道。为此本文着重对全国油桐林地的土壤类型进行研究。     

油桐北移

过去有人认为油桐在秦岭以北不能种植。解放后,党对经济林生产非常重视,油桐不仅在陕南得到迅速恢复和发展,而且在秦岭以北的关中地区也进行了引种。据我们1965年和1973年在周至等11个县(市)的调查,不少地方引种成功,现已开花结实,传种接代(见图)。当地群众在引种过程中,积累了宝贵的经验。一、关中地区的自然条件关中地处北纬34-     

陕西油桐资源及其发展途径

油桐(Aleurites fordii Hemsl.)原产我国。桐油是我国的传统出口物资,常年出口量约占世界总销售量的60%左右。目前在内需外销上,桐油都是国家的紧缺物资。我省油桐面积较大,也是全国重要产区之一。为了适应四化建设的新形势,加快我省油桐生产的步伐,笔者根据多年野外调查资料和有关文献记载,就我省油桐资源及其发展途径略陈己见,谨供参考。一、我省油桐生产现状1.历年生产情况:我省种植油桐有悠久的历史,解放前所产之桐油多经汉江、丹江水运武汉出售。据贾伟良先生的“中国桐油之研究”记载,1946年我省桐油产量为3.84万斤,产地有陕南24个县。解放后,由于党和政府重视桐油生产,产量显著提高,由1950年的675万斤,增长到1981年的1577万     

贵州省油桐良种化

我省是全国油桐的中心产区,各地均有栽培油桐的习惯,总面积为500万亩。其中75%栽培于田边地角或桐农混种,还有数目较多的零星栽植。我省常年产桐籽6,000万斤,而来自纯林经营的产量不足10%。油桐良种及丰产栽培管理技术是油桐丰产、稳产的两大措施,而桐农混种和零星栽培的     

四川省武隆县油桐资源综合考察报告

针对近几年来我国油桐资源急剧减少、油桐生产严重萎缩的现状,对位于我国油桐中心产区并具有一定代表性的四川省武隆县的油桐资源和生产状况进行了综合考察,查清了该县的油桐资源现状.找出了油桐资源减少、桐籽出油率降低的主要原因,提出了解决现存问题的途径和方法,为恢复和发展该县及我国的油桐生产提供了一定的决策和技术依据。     

万县市油桐良种繁育技术应用效益分析报告

万县市油桐良种繁育技术应用效益分析报告重庆万县市油桐科研协作组１９８７年由万县市林业局牵头，各区、县林业局协作，组建了万县市油桐科研协作组，开展了米桐优良家系配合力和种内朵交组合试验研究，在生产中除对决选出的优良单株和已建普通种子园加强管理外，又着手...     

油桐生物学研究进展

【目的】通过总结油桐生物学研究取得的进展,提出目前油桐相关基础研究中亟待解决的问题,并提供一定的研究思路,以推动油桐产业的进一步发展。【方法】收集近5年来油桐生物学方面的研究报道,结合油桐独特的生物学特性进行分析和总结。【结果】多方面的油桐生物学研究工作得以开展,涉及花性别分化、光合生理、逆境生理、基因组研究、分子标记、油脂合成机制和组织培养等。油桐基因组测序的完成有助于发掘一批新的参与油脂合成以及抗病相关的基因;同时,基于油桐全基因表达的e FP browser被建立起来,对于油桐基因功能的研究具有重要的推动作用。转录组和蛋白质组的分析表明雌花的发育受到茉莉酸、一些重要的转录因子以及与花分生组织活性相关基因的影响,并且雌花的最终形成与细胞程序化死亡相关基因有着紧密的联系。SSR、ISSR和SNP等类型分子标记的开发揭示了油桐的遗传多样性,为油桐的品种选育奠定了基础。【结论】组学研究有助于更深入揭示油桐油脂合成和花性别分化的机制。油桐的组织培养技术也已比较成熟,为油桐优质苗木生产提供了技术支撑。目前关于油桐光合生理和逆境生理的研究强调了矿质元素和环境因素对盆栽油桐幼苗生长的影响,但缺少...     

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.