甘肃省杨树速生丰产用材林栽培区和栽培类型划分的研究

杨树Populus是我国主要速生用材树种之一,尤其是北方农区栽培极为广泛。杨树速生丰产用材林栽培区以栽培类型的划分,对发展我省杨树生产具有重要指导意义。本项工作,在调查研究的基础上进行了定量分析(气象要素)区划,全省分4个栽培区5个亚区11个栽培类型。本文就划分的依据、方法、分区特征(含发展杨树丰产用材林的重点地区、适用品种、宜林土壤)、立地因素、类型及其技术措施做了论述。     

速生杨树良种在辽宁省的区域栽培

对当前辽宁省栽培推广的主要速生杨树品种，按着影响其生长的气温、降水、土壤等主导因子，根据不同品种的生物生态特性，进行了大体的自然栽培区划。在栽培区划中将我省区分为西部丘陵干旱区、西北部沙旱瘠薄区、辽北低丘平原半湿润区、辽河平原半岛半湿润区及东南部湿润区、东部山地低温区、辽河下游低地盐土区等6个不同栽培生态区。把当前生产中主要栽培的杨树品种，划分为喜温型、较喜温型、中温型、较抗寒型、耐碱型等类型。并在上述各生态区内进行了布局，为以后栽培推广提供了适地适树、适地适品种的依据。     

速生杨丰产栽培技术要点

<正>近年来,杨树木材价格持续上涨,人们栽植速生杨树的积极性很高,每年新造杨树速生丰产林的面积很大,对增加农民收入,促进林业发展起到了一定作用。但也存在造林地、品种选择不当,杨树生长状况不良,易发生病虫害的情况,尤其是栽植过密的现象普遍而严重,影响其生长,难以培育大径材,不能充分发挥速生杨树的经济效益。现将速生杨树栽培要点和主要病虫害防治方法介绍如下,供参考。     

杨树速生丰产林水分生理指标的研究

为了探讨杨树速生丰产用材林在我省黄土高原栽培区域和栽培类型条件下的水分代谢特点,比较不同杨树品种(系)之间和不同栽植密度条件下林木生理指标的变化,了解水分代谢与林木生长规律的关系,选择速生丰产的杨树优良品系,确定最佳栽培措施提供依据,我们对庆阳试验区栽培的速生丰产样板林,进行了部分生理指标的测试分析。测定结果证实:树种应选择北京杨0567号;初植密度:8年为一轮伐期的应选择4×4m,10年为一轮伐期的应选择5×5m,而7×7m栽植密度的杨树人工林,在第10年蒸腾耗水量增大,水势继续上升,正值速生高峰,应延长轮伐期。     

关于我省杨树害虫的综合防治意见

<正> 杨树具有生长快、适应性强、易于繁殖和有一定经济价值的特点,深受群众欢迎,是目前广泛栽植的速生树种之一。当前,各省(区)已经把栽植杨树人工林作为解决平原、湖区、丘陵和岗地木材的重要途径。近年来,我省杨树造林也有了迅速的发展,引种、栽培了欧美杨Ⅰ-69/55、Ⅰ-72/58、Ⅰ-214及沙兰杨等几个无性系品种,仅据1983年春止,全省共栽植了杨树3,552万株,其中片林498,600亩,意杨速生丰产林占25万多亩,林网面积达79万亩。随着杨树造林的迅速发展,要想使杨树达到速生、优质,丰产,除了实行集约经营,采用良种壮苗和科学栽培管护外,还必须重视和做好病虫害防治工作,否则,就可能降低造林效果甚至导致失败。为此,就杨树害虫的综合防治谈一些粗浅认识。     

玛引14号杨、玛引3号杨材积 增长量达到我区杨树速生丰产先进水平

杨树是我区的重要速生用材树种,为了选出适合新疆北疆地区速生丰产的杨树品种,我场和新疆八一农学院合作,于1975年4月,营造了50亩杨树品种汇集圃。共栽植有玛引14号杨、玛引3号杨、合作杨、健杨、北京杨、莫斯科杨等161个品种(品系)。经过10年试验取得了显著效果,玛引14号杨、玛引3号杨生长最快,材积增长量达到北疆地区     

杨树品种对比试验初步研究

近几年在江淮丘陵地区的林业生态建设中，杨树以其生长迅速、用途广泛，材质优良且能短期内快速绿化而被广泛作为营造速生丰产用材林的主要树种。但是目前栽植的杨树品种多、乱、杂，各品种的生长量和适应性差别很大。为了适应林业生产的需要，推进杨树产业的发展，选择出适宜在江淮丘陵区进行推广栽培的优良品种，我们于2005年在来安县施官村贾龙村项目实施地进行了5个杨树品种的对比试验。     

杨树人工林冻害综合防治技术的研究(I) 杨树人工林冻害及冻裂的周年发生规律

1 杨树人工林冻害的危害性杨树是我国北方主要栽植的速生树种之一。据1983年统计,全国有20个省、市、自治区发展杨树造林,保存面积约1亿亩。目前,各地区还在不断扩大栽培面积。黑龙江省不仅在西部地区栽植了大面积杨树人工林,在东部山区,为缓解森林资源的危机也营造了     

晋南地区杨树品种生长适应性研究

为了筛选适宜晋南地区栽培的杨树品种,选择21个杨树优良品种,按照完全随机区组设计进行栽植,调查其年生长量、生长势以及病虫害等情况,通过对测定指标进行打分来评价杨树的生长适应性.结果表明,树高和胸径年均生长量最高的是鲁林1号、北抗1号、鲁林2号、鲁林3号.生长适应性分析表明,21个杨树品种均适宜在晋南地区栽培,其中,美洲...     

通道绿化杨树速生丰产林主要指标研究

笔者研究确定了山西省通道绿化主要杨树品种或树种组速生丰产用材林的计算标准年龄,各栽培区、各树种组在参考栽培密度下计算标准年龄时的速生丰产用材林生长指标的底限,各树种组不同林龄速生丰产用材林生长量指标以及各栽培区、各树种(组)速生丰产用材林的轮伐期,并提出了通道绿化速生丰产用材林的建设规模、造林成活率和保存率的要求。     

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.