侧柏毒蛾防治研究中的若干问题

侧柏毒蛾(Parocneria furva Leech)是侧柏林的重要食叶害虫.徐州地区侧柏林面积30余万亩,自1963年侧柏毒蛾出现大发生以来,为防治此虫投入了大量的费用.笔者在70年代初曾开展了侧柏毒蛾防治研究工作;从1978～1981年曾与江苏省林科所汪永俊等有关同志合作,对侧柏毒蛾的生物学特性、发生规律和防治技术进行了较为系统的研究;近几年来江苏省林技站、徐州市森防站、铜山县赵疃林场等单位对侧柏毒蛾的地面超低量喷雾和防治指标作了研究.本文着重论述侧柏毒峨防治研究工作中的一些重要问题,并对今后工作提出一些意见,以供参考.1 生物学特性1.1 越冬虫态杨有干在1956年对北京地区侧柏毒峨进行研究时认为此虫以幼虫越冬,实际上他当时仅仅是根据室内饲养作出的推断,而忽略     

侧柏毒蛾生物学特性研究

侧柏毒蛾Parocneria furva (Leech)是侧柏的主要食叶害虫之一。在山东普遍发生,近年来有发展趋势,据在长清县大峰山林场对25～32年生侧柏林调查,有虫株率高达100％,每株有虫多达476头,林木受害后,逐渐变黄枯萎,甚至枯死。笔者于1990年开始对侧柏毒蛾生物学特性进行了研究,现报道如下。     

侧柏毒蛾研究综述

侧柏毒蛾是侧柏的最主要害虫。该文对各地有关侧柏毒蛾发生与危害特点、生活史、生长发育与环境的关系以及测报与防治方面的研究进展情况进行了总结。     

侧柏毒蛾及其天敌

侧柏毒蛾及其天敌刘玉德，翁殿伊（遵化市国营东陵林场０６４２００）（河北省林业科学研究所）关键词侧柏毒蛾，形态特征，生活习性，除治方法，天敌侧柏毒蛾是华北北部山地主要适林树秤侧柏的主要食叶害虫，幼虫取食叶片尖端，嫩叶幼芽为害更重，受害叶片仅留基部，随后...     

侧柏主要害虫及其防治要点

侧柏是我国应用最广泛的园林绿化树种之一。为了更加卓有成效地培育、开发和利用侧柏，该文就以侧柏为寄主的侧柏毒蛾、侧柏松毛虫、柏大蚜、双条杉天牛和柏小爪螨的地理分布、生物学特性和防治方法等做出全面系统总结，借以为生产实践提供服务。     

侧柏毒蛾在桧柏上的发生规律与防治

对侧柏毒蛾在桧柏上的为害特点进行了调查,并观察记载了其生活习性,提出了一些有效的防治方法。     

侧柏种子银蛾生态学特性研究

侧柏种子银蛾是取食危害侧柏种子的主要害虫,该虫以幼虫在侧柏球果内蛀食种子。作者通过4a来在涉县定点、定株、定时对侧柏种子银蛾生物学特性观察,基本掌握了该虫在涉县的生物学特性。该虫在涉县危害侧柏种子,1a发生1代,以蛹在树干翘皮缝中越冬。     

利用气象因子预报侧柏毒蛾的方法研究

利用现有试验结果和统计、调查资料 ,分析了江苏省徐州市侧柏毒蛾与气象因子的关系 ,建立了气象因子与侧柏毒蛾发生关系的预报方程 ,为开展防治工作提供依据。     

柏肤小蠹的生物学特性的观察

柏肤小蠹是侧柏的主要蛀干害虫，在徐州地区每年发生２～３代，以幼虫及成虫越冬，本文论述了柏肤小蠹在徐州地区的年生活史和各虫期的主要生物学特性，初步掌握柏肤小蠹发生与环境间的关系。     

侧柏毒蛾活雌虫性诱雄虫试验

在林地利用未交尾的侧柏毒蛾活雌虫诱杀雄虫,每天以6～9时最佳,诱虫有效期可达6～7天;平均每头雌虫每天诱杀雄虫149.45～415.40头;水盆式诱捕器优于纸板粘胶式诱捕器。试验区虫口密度下降率为98.7％,对抑制侧柏毒蛾的发生有明显作用。     

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.