彰武松嫁接技术

通过对樟子松实生苗及其与彰武松的嫁接苗生长对照,研究了樟子松嫁接彰武松的可行性,表明樟子松嫁接彰武松成活率平均为77．3％,嫁接苗在嫁接后1a、2a高度生长分别高于樟子松实生苗36．0％和44．0％,在嫁接后9a,高度和地径生长分别高于樟子松82．0％和47．0％,以樟子松为砧木嫁接彰武松可以在北方推广。     

彰武松的特性及嫁接繁育技术——以大同九梁洼林场为例

彰武松是山西省杨树丰产林实验局于2005年从辽宁省引进的针叶树种。笔者从彰武松的起源、形态特征、生物学特性3个方面介绍了彰武松的特性,并在山西省大同市九梁洼林场以樟子松为砧木、彰武松为接穗进行了嫁接试验,总结了彰武松嫁接繁育的关键技术,为山西省北部地区丘陵风沙区、龙岗火山厚土区彰武松的繁育提供技术指导。     

彰武松嫁接繁育技术

彰武松是辽宁省固沙所1990年在彰武县章古台地区发现培育的造林树种,其特点是生长旺盛、嫁接愈合能力强、抗旱能力突出,生长快等,通过嫁接繁育彰武松表现了优良的生态、生物特性,是具有发展前途的优良树种。文章从接穗管理、嫁接地选择以及嫁接技术等方面介绍了彰武松嫁接苗木繁育技术。     

彰武松无性系早期生长的初步研究

为研究彰武松早期生长特性,对彰武松优树和优良型樟子松进行嫁接对比试验。研究表明,彰武松树高生长量显著地高于优良类型樟子松,１９９５～１９９７年３年彰武松的平均树高生长量是优良类型樟子松的１５６６％;在不同立地条件、不同年份,彰武松的树高生长量也有显著差异;通过对早期生长的彰武松生理指标进行测定,反映出彰武松比樟子松更抗旱。     

彰武松嫁接繁殖技术

彰武松是赤松的天然杂交新变种，表现出优良的速生性、抗旱性和抗病性等，现已成为“三北”地区推广应用的优良树种。笔者从接穗的准备、砧木的选择、嫁接时间、嫁接方法，及嫁接后的管理几个方面对彰武松的嫁接繁殖技术进行了初步研究，以期为彰武松的大面积繁育和推广提供参考。     

不同干旱环境对赤松、樟子松、彰武松生理的影响

选择赤松、樟子松、彰武松3年生苗木为试验材料,研究植物体在极端干旱环境内生理生化的变化。结果表明:(1)正常状态下叶比导率(LSC)表现为彰武松赤松樟子松;木质部导水率损失百分数(PLC)为赤松彰武松樟子松;边材导水率为赤松樟子松彰武松,叶片水势日间平均樟子松最高,赤松清晨水势最低,丙二醛含量彰武松最高,3树种性状各有高低。(2)随着干旱胁迫强度的增加,3树种叶片水势和枝条导水性均呈下降趋势;木材栓塞程度和丙二醛含量呈增加趋势,3树种的PLC均值在轻度胁迫时达到20%,中度胁迫时达到32%!40%,重度胁迫时达到52%!65%,重度干旱胁迫已经对枝条的脆弱性产生了影响,但仍然较自然干旱下的重度胁迫所造成的导水率损失(80%)要小,PLC增加顺序为樟子松彰武松赤松;丙二醛含量在轻度干旱中变化并不明显,但中度和重度时有明显增加,增至20~25 mmol·g-1,增幅顺序为彰武松赤松樟子松。     

彰武松嫁接繁育技术要点

彰武松是赤松的天然杂交新变种。通过彰武松的引种和嫁接繁育、观察其苗期的生长及成活情况,表现出速生、抗旱和适应能力强等特性。     

彰武松的现状及发展前景

彰武松是赤松的天然杂交新变种。表现出速生特性,具有明显的抗旱性和抗病性。是三北地区推广应用的优良树种。但彰武松良种及苗木的供应量明显不足,主要原因是彰武松纯种少;另一原因无性繁殖的嫁接苗木有限,不适于扩大推广繁殖。采取先进的扦插繁殖技术,形成一套成熟的彰武松的无性繁殖技术,以利于良种的开发和推广。     

山西北部彰武松引种试验初报

文章以山西北部风沙区为彰武松引种试验区,以辽宁北部的彰武县为种源地,进行引种试验,根据嫁接成活率和生长量表现,山西北部风沙区适宜彰武松生长,生长量超过油松和樟子松,抗逆性表现优良。     

彰武松在北京地区的嫁接繁育效果分析

以樟子松(Pinus sylvestris var.mongolica)为砧木,从嫁接时间、接穗的切面长度及来源等方面对彰武松(Pinus densiflora var.zhangwuensis)嫁接技术进行一系列试验。结果表明:在嫁接时间方面, 4月下旬到5月上旬嫁接可以保证较高的成活率;在接穗切面长度(L)方面, 6.0≤L<8.0 cm可以保证较高的成活率;在接穗来源方面,外地接穗和本地接穗的嫁接成活率差异不显著,但考虑到运营成本的问题,选择本地接穗更为合适。研究结果可为彰武松在北京地区的繁育推广提供一定的参考依据和技术支撑。     

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.