银中杨栽培及经营管理技术研究

银中杨系人工杂交新品种，研究认为，营造银中杨应选择充分熟化的土地，采用全面整地方式；应用２ａ生根桩及二根一干、二根二干苗造林；造林密度根据材种不同可采用２ｍ×４ｍ、３ｍ×４ｍ及４ｍ×４ｍ株行距；银中杨与胡枝子、云杉混交具有促进生长作用；造林后要及时进行修枝和必要的施肥管理。     

日本落叶松种内杂交亲本配合力分析

对９年生日本落叶松半双列杂交后代生长性状的配合力分析结果表明：树高、胸径的一般配合力方差分别占总遗传方差的８３．６５％、５１．８７％，均占优势。说明日本落叶松的生长性状主要受基因的加性效应所控制。树高、胸径的狭义遗传力分别为０．６５、０．４３。根据一般配合力效应和特殊配合力效应，筛选出优良杂交亲本为：草－１３、草－８２；优良杂交组合为：草－１３×草－６；草－８２×５０３；草－８２×永－１１。     

银中杨栽培技术研究

银中杨系人工杂交新品种。应用数学方法进行分析、筛选，提出了造林的具体指标和措施。研究认为，应选择充分熟化的立地条件，采用全面整地方式，应用二年生根桩及二根一干、二根二干苗造林；造林密度根据材种不同可采用２ｍ×４ｍ、３ｍ×４ｍ及４ｍ×４ｍ；营养元素合理施肥的比例是：４Ｎ：１Ｐ：３Ｋ：４Ｃａ：１Ｍｇ；银中杨与胡枝子、云杉混交具有促进生长作用。     

蜡蚧轮枝菌防治湿地松粉蚧的研究

应用蜡蚧轮枝菌防治湿地松粉蚧的试验结果，用其２．５×１０７／ｍｌ和１．７×１０７／ｍｌ的孢子液室内防治湿地松粉蚧，校正死亡率分别为８６．７％和６５．９％；林地用其每公顷喷孢量为３３×１０１２和１６．５×１０１２个孢子防治湿地松粉蚧，校正死亡率分别为９２．７％和９９．５％。     

皖东石质丘陵造林试验研究初报

５年的试验研究结果表明，土壤厚度、整地穴规格、适栽树种、造林用苗、抚育方法等都对石质丘陵造林成活率和保存率产生影响。土层越厚幼林保存率越高；整地穴规８０×８０×７０ｃｍ的造林平均保存率９６％，比整地穴规４０×４０×３０ｃｍ的造林保存率高２０％，比铲草皮后边挖小明穴边造林保存率高３７％；栽植火炬松容器苗幼林保存率７６．２％，比栽植火炬松裸根苗保存率高１７．２％；全面松土除草或以耕代抚幼林平均保存率９３％，比株周圆块状、规格为１００×１００ｃｍ抚育保存率高７．４％     

17个杨树无性系造林比对比试验初报

１９９１年春由中国林科院引进２９个杨树新杂交Ｆ１无性系，经２年苗期对比试验，选出鲁克斯杨×－４，鲁克斯杨×－３等１５个比较适宜本地生长的无性系，又以锦县小钻杨和沙兰杨为对照，于１９９３年春进行造林对比试验。结果表明：鲁克期杨×－４是表现最好的无性系，平均高生长达３５１．７ｃｍ，平均胸径达２．３３ｃｍ，与对照呈极显差异。鲁克期杨×－３，鲁克斯杨×天然杂种是表现较好；鲁克斯杨×青杨１３、鲁克斯杨×青     

海滨重盐碱地白刺人工造林技术研究

１９９３～１９９７年在东营市河口区济南军区生产基地对海滨重盐碱地白刺人工造林技术进行了研究。结果表明，白刺是盐碱地绿化的好树种；白刺种子休眠期长，冬季沙藏可打破休眠提高发芽率；重碱地造林以容器苗为主，大田苗为辅；整地方法以“两年整地、两遍耕翻、两次耙地的整地方式最好。白刺造林适宜栽植密度２ｍ×３ｍ。     

毛乌素流动沙丘樟子松人工林不同初植密度对土壤性状的影响

通过对樟子松人工林不同初植密度对土壤性状影响的研究，结果表明：（１）樟子松固沙改土效果显著，有机质含量比无林地有较大提高；（２）在无降水条件下，林内土壤含水量有所下降；（３）不同密度樟子松改土效果不同，以２ｍ×２ｍ为最佳，２ｍ×４ｍ最差。     

河南省塑料袋容器育苗应用技术研究

通过试验研究，筛选出侧柏、油松、火炬松塑料袋容器育苗的容器规格分别为：３．８×１２ｃｍ或５．１×１２ｃｍ、６×１３ｃｍ、８×１２ｃｍ，营养土配方分别为：羊粪１０％＋上杂肥３０％＋黄心土５９．８％＋复合肥０．２％、黄心土３８％＋腐殖质土３０％＋土杂肥３０％＋复合肥２％、火烧土３０％＋黄心土５７％＋菌根土１０％＋过磷醚钙３％，容器苗栽植成活率高于裸根苗７～８２％。１９９１－１９９４年培育容器苗８．６亿株，栽植平均成活率达９５％，为加速我省荒山绿化发挥了重要作用。     

樟子松杂交亲本及杂交组合选择阶段研究

选择樟子松４个优树产地１６个优良无性系进行杂交，共获得３２个组合。１９９４年造林，１９９６年对试验地进行调查分析，结果树高生长量大于杂交混合种子生长量的有２３个组合，占７１．９％；地径有１６个，占５０．０％。树高、地径一般配合力效应值较大的亲本，与其它亲本杂交的生长量也较大。根据各组合生长量与一般配合力效应值大小选择出较好的杂交组合有Ｋ４４×ＴＫ１８、Ａ６６×７５０６、ＧＫ１８×ＧＫ１５、Ａ６６×Ａ５、ＧＫ１５×Ｋ４１和Ｋ４４×Ａ６２等。树高的一般配合力效应值以卡伦山产地的较大，地径则以罕达盖产地的较大     

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.