沙松扦插繁殖技术研究

以沙松硬枝和嫩枝插穗为材料进行正交扦插试验,研究穗条母株年龄大小、药品种类、质量浓度、处理时间以及基质不同种类、穗条不同类型与不同着生部位对生根的影响,结果表明:影响硬枝和嫩枝扦插生根的主要因素均为穗条母树年龄大小,年龄越小,生根率越高,最优处理组合均为4~10 a母树穗条,用200 mg·L-1ABT1号生根粉浸泡12 h,生根率分别为21.4%、63.9%;嫩枝扦插生根率高于硬枝扦插,差异达到极显著水平。采用1/2珍珠岩+1/2河沙混合基质生根效果最好。穗条不同类型扦插生根存在差异,一级侧枝截制的穗条生根性状优于二级侧枝穗条和顶芽穗条,下部枝条截制的插穗生根率和根系效果均高于上部枝条。     

沙地柏硬枝扦插繁育试验研究

本试验设置生长调节剂、扦插基质、枝条不同部位穗条3个处理因子,通过统计不同处理插穗的生根率、平均生根数和平均根长,研究各处理对沙地柏硬枝扦插繁育生根的影响。试验结果表明:不同生长调节剂、不同基质、不同部位穗条对插穗生根影响达显著水平,用0.6%GBT处理穗条生根率最高;以河沙为基质,插穗生根效果最好;枝条中部穗条扦插生根效果最佳。沙地柏扦插最佳的处理组合是枝条中部穗条用0.6%GBT处理,在河沙基质中进行扦插。     

栽培基质和母树年龄对沙棘硬枝扦插生根的影响

通过开展不同扦插基质和不同采枝母树年龄对沙棘硬枝扦插生根影响试验研究,结果表明:(1)不同基质扦插硬枝的生根率、根长和根数差异显著,以细河沙与腐殖土3∶1的混合基质扦插,生根率最高(91%),根系较发达,根系较长(4.32 cm)、根数多(6.4条),硬枝扦插较为适宜的基质。(2)取枝母树年龄越小,插穗生根效果越好,硬枝扦插母树以5～8 a为宜。     

加拿大铁杉扦插育苗技术

以加拿大铁杉的嫩枝、硬枝为繁殖材料,对扦插的基质、处理模式和环境控制进行筛选研究,确定出适宜加拿大铁杉嫩、硬枝扦插的条件。硬枝扦插分前期温室人工和后期全光自动喷雾两个阶段,嫩枝扦插分前期全光自动喷雾和后期温室越冬两阶段。适宜加拿大铁杉嫩枝扦插因素配比为:中上部穗条+珍珠岩+300mg/L1号ABT生根粉溶液,当年生根率达28.5%,竖年春生根率可达69.2%。适宜硬枝扦插因素配比为:中部穗条+沙∶珍为1∶2的基质+500mg/L1号ABT生根粉溶液,当年生根率达47.6%。     

大叶冬青引种扦插试验及驯化技术

选取野生大叶冬青(Ilex latifolia)当年生半木质化枝条为母穗,进行不同基质、不同扦插季节和不同生根激素对其扦插生根的影响试验,结果表明,基质对插穗生根的影响较大,采用蛭石粉+河沙+火烧土,插穗生根率高、根系长、侧根多;不同生根激素对插穗生根影响较大,其中以ABT1生根率最高,达81％,比CPD生根粉高30％,其次是NAA生根粉,达60％,方差分析显示各处理间生根率差异显著;扦插时间以夏季扦插穗条生根率最高,其次为春季,秋、冬二季扦插成活率低,半木质化穗条生根率最高,其次为顶芽,最后为硬枝;选取半木质化的穗条,并用ABT1生根粉进行处理,采用蛭石粉+河沙+火烧土基质,在夏季进行扦插,取得成功.     

亚美马褂木扦插繁殖技术研究

以亚美马褂木优良品种为对象,采穗圃当年生穗条作插穗,研究了扦插季节、基质、植物生长调节剂等对生根的影响.研究结果表明:(1)不同季节扦插生根率显著不同,夏季扦插生根率最高为57.3％,其次是秋季扦插(40.3％),生根率最低是春季扦插(24.7％).(2)不同扦插基质生根率差异极显著,珍珠岩+蛭石+河沙(1:1:1)为...     

园林树种金蒲桃扦插繁育技术研究

以园林树种金蒲桃树枝条为材料,利用扦插繁育技术,研究不同插穗类型、不同基质、不同季节、不同生根剂和浓度对生根的影响。结果表明,选择金蒲桃嫩梢和半木质化穗条作为插穗的生根率、平均根数和平均根长没有差异,但都显著高于硬枝。金蒲桃插穗在黄心土与沙壤土混合(质量比=1∶1)基质中生根率最高(84.67%),平均根数最多(6.80条),平均根长最长(7.06 cm),是金蒲桃扦插最佳基质。插穗在春季或秋季扦插时根生长情况优于夏季,春季或秋季较适宜金蒲桃穗条扦插。插穗在ABT浓度为300 mg/L或NAA浓度为300 mg/L时生根情况较好。     

构树无性系嫩枝扦插育苗试验

研究表明,构树无性系间其穗条扦插生根率有显著差异,参试无性系穗条扦插生根率变幅为91.8%~43.8%。本试验筛选出了扦插生根率高的5个无性系即湘构P 02、湘构P 04、湘构P 05、湘构P 09、湘构P 12;穗条带1~2片叶可显著提高穗条的生根率;多菌灵不同浓度、GGR生根剂不同浓度处理对穗条生根率没有显著影响;不同基质对穗条扦插生根率有显著影响,以纯黄心土作为扦插基质效果最佳。     

花梨萌芽条扦插育苗技术研究

通过对花梨穗条采用不同扦插基质、不同激素多种浓度处理、不同枝龄的穗条扦插、穗条不同部位的扦插、不同季节扦插几个方面的对比试验,结果表明:用红壤土、河沙和椰糠(6∶3:1)扦插基质,IBA在150~250ppm浓度范围、下部穗条,一年生穗条、冬春季扦插能有效提高花梨扦插育苗的生根率和成活率。     

红锥采穗圃营建及其穗条的扦插育苗试验

红锥是我国极具推广和开发价值的南亚热带优良速生珍贵用材树种。为了获取红锥大量扦插繁殖用的穗条,营建其采穗圃,经大量的试验研究,探索到了较为完备的红锥采穗圃营建技术。通过对所采穗条开展的扦插育苗试验,探明了不同的穗条处理方式、不同扦插季节、不同扦插基质、不同生根药物和采穗母株对其穗条扦插生根的难易。致使红锥穗条的扦插生根率最高可达90%以上。     

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.