高频微波速杀松材线虫试验

总结了高频微波处理松材线虫病疫木的试验经验,以疫木中的松褐天牛和松材线虫死亡率达到100%且不损害疫木材质为目标,探索了工业上常用规格松木包装的最少处理时间和最适宜的微波发射量,为工业生产上的设备研制开发,积累相关实验参数.     

利用松褐天牛早期监测松材线虫病技术研究

在室内对因松材线虫病死亡马尾松树干羽化出的松褐天牛测定结果表明，８６％的天牛携带松材线虫，平均１头天牛携带３５９０条。林间引诱松褐天牛，在没有松材线虫病的健康林地，分离不到松材线虫，而松材线虫病发生区引诱到的天牛６５％携带松材线虫，携带量在１０１～５０００条之间。在５月下旬～６月中旬，应用黑光灯，新鲜马尾松木段，引诱松褐天牛１０头能上，采用松材线虫常规分离方法，可以早期监测松材线虫病的发生情况。     

喷蒸法在松材线虫病疫木处理中的应用试验

松材线虫病主要通过携带病原线虫的松木及其制品人为运输进行传播。对疫木进行快速、彻底的除害是控制疫情蔓延的重要途径之一。为了探索经济、高效、安全的疫木处理方法，2004年3月以来，我们尝试采用喷蒸法处理疫木，取得了良好的效果。喷蒸法即是在在使用喷蒸的条件下快速提高烘房内温度，杀灭疫木中的天牛和松材线虫。试验表明：6个小时烘房内温度即能达60℃以上，9个小时松褐天牛和松材线虫死亡率都达100％。较传统方法，节约除害时间6小时，提高工效近2倍。综述如下：     

放养管氏肿腿蜂防治松褐天牛试验成效分析

松材线虫病的传播,主要是以媒介昆虫松褐天牛携带松材线虫感染健康松木致病.根据有关研究数据证明,松褐天牛携带线虫率达62.5%,携带线虫量为4601～12737条/头,最高达到71740条/头.因此,松材线虫病的除治,其根本要素是对松褐天牛的积极除治,防治松褐天牛即直接影响着松材线虫病的防治效果.     

薄膜覆盖熏蒸法在死松树除害中的应用效果初步调查

为探明山区使用覆盖熏蒸法在死松树除害中的实际效果及可行性,进行了试验。经调查,薄膜覆盖药物熏蒸除害超过60d以后,松材中仍发现松材线虫病传播媒介昆虫--松褐天牛幼虫成虫活体。故试验结果表明,在山区进行松材线虫病死亡松木除害处理时,用薄膜覆盖熏蒸法除害处理法缺乏可行性。     

松材线虫病的诊断方法探讨

控制松材线虫病的关键是及时诊断疑似疫木、疫点,既能采用有效、简单、易行的方法进行诊断,且能有的放矢地进行诊断。文章根据广东省松材线虫病疫区的特点,对林间枯死松树外观症状诊断法、林间枯死松树体内线虫的分离鉴定法和松褐天牛引诱剂辅助诊断法等3种松材线虫病的诊断方法及其适应范固进行探讨。     

松材线虫病疫木剥皮处理对松墨天牛侵入的影响

松材线虫病疫木的无害化处理是松材线虫病防治工作的核心措施。为探寻高效、环保的林间疫木就地无害化处理技术,采用未被松墨天牛侵入的枯死松树(疫木)树干及伐桩,经剥皮处理后开展天牛及松瘤象等其他蛀干害虫侵入情况试验。结果表明:林间未被松墨天牛蛀入的疫木木段和伐桩,经剥皮处理后均未发现松墨天牛侵入的情况,但仍可受到小蠧等害虫的入侵。未剥皮的树干木段,松墨天牛幼虫仍可以蛀入;未剥皮的伐桩60%有松墨天牛蛀入孔和羽化孔。剥皮处理树干和伐桩可以阻止松墨天牛侵入,防止松材线虫病传播扩散,是林间疫木就地无害化处理的有效措施之一。     

松材线虫病被害木伐桩灭虫试验研究

通过林间调查、根桩解剖、线虫分离等试验,结果表明,在伐桩、木质部内存在数量较少的松褐天牛越冬幼虫;该幼虫次年羽化成成虫,具有传播松材线虫病能力。通过对不同高度伐桩中天牛活体数量调查和农药处理伐桩试验,认为在伐桩高度低于５ｃｍ时,用２０％倍硫磷油剂＋０号柴油２０倍稀释液浇淋伐桩,具有既简单又彻底的杀灭伐桩内天牛和控制松材线虫病的良好效果。     

松材线虫病疫木安全利用新途径

该文在实地调查的基础上研究了利用松材线虫病疫木种植茯芩并杀死其中的松材线虫、松褐天牛达到安全利用的方法。研究表明:疫木种植茯苓第63天,样木中的松材线虫可全部死亡;第77天松褐天牛可全部死亡,种植240 d后,茯苓可采收,每立方米疫木可收益约1 100元。对利用疫木种植茯苓在种植技术、时间及安全性方面进行了可行性分析,并对经济效益和对生态环境的影响进行了评估。     

老疫区松材线虫病持续控制技术研究

2005～2009年在广州市松材线虫病老疫区系统开展了疑似病死松树的早期诊断、应用引诱剂和林间释放花绒寄甲控制松褐天牛、清理病死木套袋熏蒸和疫区松林植物群落结构改造等持续控制技术研究.结果表明:疫区内松树枯死木松材线虫的检出率为22.1%～55.4%.诱到松褐天牛成虫19 853头,每个诱捕器的诱虫量为14.06～24...     

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.