中华松梢蚧若虫期防治试验

通过用1.2%烟碱、苦参碱乳油、40%毒死蜱乳油、40%杀扑磷与柴油1:10对中华松梢蚧若虫进行喷烟,和用40%杀扑磷1 000倍液对中华松梢蚧若虫进行弥雾防治试验,结果显示40%杀扑磷喷雾防治效果最佳,防效达85%.     

四种杀虫剂对橡胶盔蚧的防效试验

2004年8月进行4种杀虫剂对橡胶盔蚧的防效试验,结果表明40%杀扑磷乳油800倍液、2.5%杀蚧乳油 800 倍液、2.5% 蛛八蚧乳油 800～1　000 倍液、40% 氧化乐果乳油 800 倍液对橡胶盔蚧 1、2 龄若虫效果显著,14d 的防效均在91.3%以上;4种药剂的 800倍液对3龄若虫、成虫的试验结果,40%杀扑磷施药后 14d 防效为 64.7%,对成虫无效;对橡胶树无药害。     

药剂防治松突圆蚧的试验初报

试验采用50%杀扑磷、25%喹硫磷药剂防治松突圆蚧，结果表明：两种药剂的500倍液，防治效果均达80%以上，对雌蚧虫的杀伤力也远优于他种农药。     

核桃桑白蚧药剂防治试验

利用40%速扑杀乳油、20%赛嗪杀扑磷乳油、5%高效氯氰菊酯白色乳剂、48%毒死蜱乳油和自制石硫合剂5种药剂在景东县文景镇者孟村核桃采穗园中进行核桃桑白蚧害虫药剂防治试验。结果表明,40%速扑杀乳油1 000倍液和20%赛嗪杀扑磷乳油1 000倍液的防治效果较为理想;5%高效氯氰菊酯白色乳剂2 000倍液和48%毒死蜱乳油2 000倍液的防治效果一般;自制石硫合剂防治效果较差。     

药剂防治中华松梢蚧若虫试验

采用不同药剂和用药方式对中华松梢蚧（Sonsaucoccus sinensis Chen）进行防治试验,施药15 d后比较虫口减退率。方差分析：不同防治地点对防治结果无明显差异,而各种药剂处理间差异显著,40%杀扑磷1 000、2 000、3 000倍液超低容量弥雾弥雾和氯胺磷30%乳油1倍液打孔注药虫口减退率在90%以上。因此采用40%杀扑磷超低容量弥雾是大面积防治中华松梢蚧经济有效的方法。     

8种化学药剂对桑白盾蚧的防治试验

用杀扑磷、毒死蜱等8种药剂对国槐桑白盾蚧Pseudaulacaspis pentagona进行林间药效试验,筛选出防治效果最好的药剂为40%扑杀磷乳油和1.8%阿维菌素乳油复配剂,防治效果达到94.65%,环保型药剂1.8%阿维菌素乳油和0.5%苦参碱水剂,防治效果分别是72.56%和71.19%,防治刺吸式口器害虫的新型农药22%氟啶虫胺腈悬浮液和22.4%螺虫乙酯悬浮液,防治效果为83.42%和84.03%。     

板栗栗绛蚧药剂防治试验

应用速扑杀、杀扑磷、快克和氧化乐果、杀灭菊酯防治板栗栗绛蚧若虫。试验结果表明速扑杀1000倍、杀扑磷1000倍、快克800倍喷雾防治15天后，栗绛蚧若虫虫口减退率为88．9％－89．99％，30天后若虫虫口减退率为93．85％－96．84％，防治效果好于氧化乐果、杀天菊酯，结合农药成本、防治效果，确定快克800倍，可作为喷雾防治栗绛蚧若虫道选农药之一。     

桑盾蚧的生物学特性观察与防治

经调查,桑盾蚧在洛南县1a发生两代,主要寄生于核桃幼树的主干、粗枝和2a生以上枝条,当年生枝、叶柄、叶片少有分布;40%杀扑磷乳油1 000倍液、1.8%阿维菌素2 000倍液、40%毒死蜱1 000倍液防治桑盾蚧效果较好,有效率都在80%以上,可在5月10-30日即一龄若虫盛期,每隔10d喷1次,轮换用药,共喷药3次。     

三种药剂林间防治麻疯树柄细蛾试验

麻疯树柄细蛾是攀西地区麻疯树主要害虫。试验利用2%阿维菌素乳油、25%三氟氯氰菊酯乳油和40%杀扑磷乳油进行了林间防治麻疯树柄细蛾试验。结果表明3种药剂中,2%阿维菌素乳油1 000倍液最为有效,防治效果为89%。40%杀扑磷乳油表现出较好的持效性。     

3种药剂防治白杨透翅蛾初孵幼虫试验

通过选用350g·L-1吡虫啉悬浮剂、30%甲维毒死蜱乳油和40%氧化乐果乳油3种药剂,每种药剂设2个浓度梯度,喷洒树干对白杨透翅蛾低龄幼虫开展防治试验。结果表明:施药后20d,6种处理无显著差异,防治效果均达到90%以上;3个药剂平均虫口减退率为97.29%。350g·L-1吡虫啉悬浮剂500倍液、30%甲维毒死蜱乳油800倍液和40%氧化乐果乳油1 000倍液可用于白杨透翅蛾低龄幼虫防治。     

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.