新技术文摘

２３个柳树品系比较试验分析甘肃省临夏州林科所对引种的２３个柳树品系,经过３年苗期、５年造林比较试验结果分析,以从江苏省林科所引种的Ｊ１７２柳品系表现最好,造林９年平均高１７９２ｍ,平均胸径２５４７ｃｍ,显著高于当地优良品种旱柳１４。其次是Ｊ１９４...     

23个柳树品系造林对比试验

对１９８６年春引进的２３个柳树品系，经３年苗期比对试验，选出了Ｊ１７２柳，Ｊ１９４，柳，意大利柳等２１个比较适宜木地区生长的品系，于１９８９年春进行造林对比试验，结果表明，Ｊ１７２柳表现最好，年平均树高生长量达２．６５ｍ，年平均胸长生长量达２．８８ｃｍ，其次是Ｊ１９４柳和Ｊ３６９柳，青刚柳和准噶尔柳，这５种柳树对褐斑病和腐烂病有较的抗性。     

短轮伐期杨,柳材的制浆性能研究

对３年生杨柳无性系木材的纤维素含量和纤维形态的测定分析表明，各无性系之间无显著差异，而同一无性系木材纤维长度则随密度提高而变长，其中Ｉ—７２杨的５个造林密度，Ｉ—６９杨的１ｍ×１．５ｍ、１ｍ×３ｍ、２ｍ×２ｍ，Ｊ—１７２柳和Ｊ—１９４柳的１ｍ×１．５ｍ、１ｍ×２ｍ、１ｍ×３ｍ以及Ｊ—３３３柳的１ｍ×１．５ｍ、１ｍ×２ｍ等１６个处理的木材均达到中级优质造纸纤维原料要求。     

黄河故道区编织柳新品种的管理技术

黄河故道区编织柳新品种的管理技术从江苏和山东引进的簸杞柳ＪＷ８－２６、杞簸柳ＪＷ９－６及博红柳、红皮柳、青皮柳、黄皮柳６个新品种，经过以簸箕柳为对照进行的品种对比试验，结果表明博红柳、簸杞柳ＪＷ８－２６、杞簸柳ＪＷ９－６的表现最好，并总结出了一套丰产...     

蓝桉、直干桉综合丰产技术试验示范

试验林采用正交设计，因素为树种、整地方式、密度、施肥，各因素取３个水平，３次重复。用生长量、生物量与投入产出进行评价。试验结果：３．５年生蓝桉、直干桉幼林最佳处理平均高９．５ｍ，平均胸径８．９ｃｍ，每ｈｍ２蓄积量７０．５１２６ｍ３，最佳处理比最差处理树高大２８．４％，胸径大３４．９％，蓄积量大１８３％。用已取得的技术成果营造的示范林，３．５年生平均高９．８ｍ，平均胸径６．５ｃｍ，累计产桉叶２．４３万ｋｇ／ｈｍ２，３年生左右，通过桉油及薪柴的收入可以回收全部造林及加工成本。     

杨树伐根嫁接毛白杨技术

选择抗虫的毛白杨树种利用杨树伐根嫁接更新，可解决杨树蛀干害虫为害区清除虫害木后的更新问题及伐根不易清除的难题，在白银灌区嫁接当年平均苗高４．６ｍ，平均地长４．２ｃｍ，平均成活率达到８５．５％。     

杉木蛀干害虫的发生和营林技术措施的防治效果

杉木蛀干害虫是人工杉木林的一类严重害虫。由于蛀干害虫的侵袭,引起杉木生长衰弱,乃至枯死。为了探讨营林技术措施对杉木蛀干害虫的预防作用,我们1966—1967年和1973年,在大安山林区对杉木蛀干害虫的发生情况,抚育间伐试验的预防效果进行了调查研究,并在总结群众经验的基础上,提出了两伐、三干净的营     

柏类引种试验研究

对柏类４个树种墨西哥柏、绿干柏、垂柏、巨柏共１２个种源的引种结果表明,不同树种和种源树高、胸径增长最大年份分别出现在造林后第４年和第５年;造林后１０ａ,各树种和不同种源树高、胸径生长差异显著,以墨西哥柏３、２、６、７号种源生长最快,树高、胸径平均值在１０．４ｍ和１５．２ｃｍ以上,其中３号种源树高最大,为１１．０９ｍ,６号种源胸径最大,为１６．９ｃｍ,分别比垂柏增加９．９％和２７．１％。各树种和种源都有倒伏现象,倒伏程度与造林树种、林龄、立地有关。     

湿地松×加勒比松杂交种引种试验研究

本试验表明引进的湿地松×加勒比松杂交种Ｆ１、Ｆ２不仅能适应当地的环境条件，且表现为明显的早期速生性，５年生平均树高、胸径分别大于湿地松（ｃｋ）７４．７％、５４．９％；早晚期相关紧密，抗逆性强，不发生冻害，是我国目前最北的种植点。     

2种蛀干类害虫引诱剂诱捕害虫效果研究

引诱剂Ⅰ和引诱剂Ⅱ是最常用的2种松墨天牛引诱剂。为了弄清蛀干类害虫引诱剂林间诱捕云南松蛀干害虫的效果,于2009～2012年每年的5～9月蛀干害虫活动期在玉溪市红塔山自然保护区2个林区设6块样地进行2种蛀干害虫引诱剂诱捕蛀干类害虫实验。结果表明,蛀干类害虫引诱剂可以诱捕到危害云南松枝梢和树干的8种害虫,1种待鉴定,1种天敌昆虫。松墨天牛、短角幽天牛、吉丁虫、木蠹象、松瘤象是云南松蛀干害虫的优势群体。连续使用害虫引诱剂能显著降低林间蛀干类害虫的虫口密度。     

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.