草河口地区班克松引种试验效果分析

班克松引种到辽宁省本溪县草河口地区造林已达12a，通过对其生物量和生长量的调查结果表明，树高、胸径生长与当地乡土速生树种红松相差无几，且根系发达、生长稳定、无病虫害。说明班克松这一优良树种在草河口地区可以达到预期引种效果。     

低丘红壤湿地松适生优良家系的筛选

历时9a，引种全国116个湿地松家系，经造林对比试验，以生长量为主要指标，以造林成活率(保存率)及对病虫害的抗性为辅助指标，筛选出了在低丘红壤地区适生的湿地松优质家系4-6、4-31、4-26、p19、p5．其9a生时平均单株材积超过优良种源54．8％，超过普种140％，是低丘红壤地区湿地松造林的首选家系。     

桐棉松引种栽培技术研究

经过５年时间对桐棉松引种育苗和造林技术研究表明；育苗地宜选海拔６００～７００ｍ向阳砂壤土旱地；最佳播种时间为清明前，不宜下基肥和施追肥；造林宜用粗壮小苗、挖大穴，最佳造林时间为大寒后立春前；桐棉松成活率、生长量与海拔高呈负相关，与温度呈正相关，生长比马尾松速生，抗逆性与马尾松相似；桐棉松在闽东海拔９００ｍ以下地区可推广栽培     

红桤木引种栽培试验

2005-2007年,从美国引进红桤木在江苏六合和安徽南陵进行引种造林试验,结果表明红桤木具有较好的生长适应性,是一个优良的速生树种。造林3 a时,平均树高生长量分别达到3.98 m和5.01 m,地径生长量达到5.9cm和7.14 cm。实生红桤木个体间早期生长差异较大,地径与苗高生长显著相关。引种红桤木4年生时已大量开花结实,进入性成熟期。     

桐棉松引种栽培技术研究

经过５年时间对桐棉松引种育苗和造林技术研究表明：育苗地宜选海拔６００￣７００ｍ向阳砂壤土旱地；最佳播种时间为清明前，不宜下基肥和施追肥；造林宜用粗壮小苗，挖大穴，最佳造林时间粝寒后立春前；桐棉松成活率、生长量与海拔同呈负相关，与温度呈相关，生长比马尾松速生，抗逆性与马尾松相似；桐棉松在闽东海拔９００ｍ以下地区可推广栽培。     

云杉引种及种源试验研究

经长达１４～１５ａ的云杉引种和红皮云杉种源试验研究表明：青海云杉从西北引入齐齐哈尔北部克拜地区造林是成功的，生长良好，树高、胸径、材积分别比对照大４．１％、１５．０％和１９．８％；红皮云杉美溪种源在该地区生长量高，生长稳定，为最佳种源，树高、胸径、材积分别比对照大５．０％、１１．９％和２７．１％；云杉早期选择是可行的，５～６ａ可作为早期选择的初选年龄。     

鄂西北秃杉引种栽培试验研究

秃杉引种栽培试验表明,秃杉在鄂西北地区具有生长快、适应性强、病虫害少等特点, 在同一立地条件下秃杉平均高生长量比杉木高36．2％,平均胸径比杉木高71．0％,为优良珍贵的速生用材树种和园林观赏树种。秃杉种源试验结果表明:种内存在遗传变异,生长量与经度、纬度呈负相关,低纬度的云南林科院种源,材积生长高于种源平均材积生长量32．1％。     

银荆引种及造林技术研究

古田县于１９８８年引种银荆获得成功。阶段性试验结果表明，银荆生长速度快，生长量高，能适应古田地区的气候条件，并介绍了银荆的生长特性以及解决造林成活率不高的关键技术措施。     

两种美国南方松在鄂南适生性的调查分析

<正> 我区自1969年引种以湿地松、火炬松为主的美国南方松以来,造林面积已达25000余亩。引种时间不长,而造林面积增加很快。目前生长较好的,11年生湿地松每亩蓄积可达8.3立方米,平均每亩材积生长量0.75立方米;而生长最差的10年生单株材积仅0.019立方米,每亩蓄积0.85立方米,平均材积年生长量仅0.85立方米。好坏之差有天壤之别。产生这     

藏柏引种造林研究

藏柏原产西藏东南墨脱、林芝及鳊北部等地，是珍贵的速生用材树种和庭园观赏树种。仁寿县引种藏柏人１９８７年开始，历经１０４上，经观测在我县引种造林生长良好，抗生强、树高、胸径和材积生长量，均优于乡土树种四川垂柏，可在我县海拔３５０ｍ～９８８ｍ之间的紫色土壤和微酸性黄壤上发展。牧季用营养袋苗造林，成活率可达９５％，该树种已在我县工程造林中作为优化树种推广，截至１９９６年底全县引种造林３４７８公顷。     

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.