落叶松小爪螨生物学特性研究初报

落叶松小爪螨是小陇山林区新发现的一种害螨，仅寄生于落叶松。该螨以两性生殖为主，雌雄比为２７９∶１；在小陇山１年可完成４代，４月上旬开始卵孵化，９月上旬开始进入枝条皮缝中越冬。其个体发育与温度关系密切，活动与取食有明显的趋嫩性、喜光性，一天中以９∶００～１６∶００时活动频繁     

水杉小爪螨生物学特性及防治研究

水杉小爪螨是在陕西汉中发现的新种，为该区水杉的主要害螨。通过对２１４ｋｍ行道树随机抽样调查，水杉受害率１００％，危害程度平均２．８级。该螨一年发生１２代，以卵越冬，为害盛期６－８月，发育历期随环境温度增高而缩短。雄成螨具第二若螨期。在自然条件下，深点食螨瓢虫等天敌是其限制因素。三氯杀螨醇和螨死净混合使用防效最佳。     

栗新链蚧发生规律及其防治

栗新链蚧在江苏徐州１年发生２代。第１代卵４月下旬孵化，５月上中旬为孵化盛期，第２代７月中旬进入盛孵期。第１代孵化期长达４０余天，有较为明显的盛孵峰期，世代重叠现象突出。第１代孵化盛期用４０％氧化乐果乳油１５００倍和２．５％敌杀死乳油５０００倍的混剂喷洒一次，虫口减退率达９８％以上。越冬成虫恢复取食后用久效磷水剂１次注射，可取得９０％以上的防效。     

水杉小爪螨生物学特性及防治研究

水杉小爪螨（ＯｌｉｇｏｎｙｃｈｕｓｍｅｔａｓｅｑｕｏｉａｅＫｕａｎｇ）是在陕西汉中发现的新种，为该区水杉的主要害螨。通过对２１４ｋｍ行道树随机抽样调查，水杉受害率１００％，危害程度平均２．８级。该螨一年发生１２代，以卵越冬，为害盛期６～８月，发育历期随环境温度增高而缩短。雄成螨具第二若螨期。在自然条件下，深点食螨瓢虫等天敌是其限制因予，暴雨是害瞒急剧下降的主要因素。三氯杀螨醇和螨死净混合使用防效最佳。     

毛白杨绣球病研究

通过接种试验确定毛白杨绣球病为毛白杨瘿螨（ＥｒｉｏｐｈｙｅｓｄｉｓｐａｒＮａｌ．）所致。在山西太谷县一年３代，以卵在毛白杨枝条上越冬芽内越冬，越冬代、第一代、第二代成螨分别发生于４月中旬、５月中旬、６月中旬，越冬卵于翌年４月上旬孵化，孵化的幼螨即在越冬芽内为害，使越冬芽一展叶就表现出危害状：叶片变小，皱缩变形，肿胀增厚，重叠密生，卷曲成团，节间缩短，丛生紫红，形似绣球。     

英德跳生物学特性和防治研究

英德跳是我国森林昆虫竹节虫目的一新虫种。在广东省英德县首次发现危害黎蒴栲林成灾得名。若虫和成虫危害黎蒴栲为主的壳斗科树叶，以成虫危害最烈。该虫在英德县１ａ发生２～３代，世代重叠。以第１、２代成虫产的卵在枯枝落叶层下越冬，翌年２月下旬卵开始孵化，５月中、下旬为越冬代成虫高峰期。在５月上、中旬使用３％６６６烟剂１５ｋｇ／ｈｍ２防治，效果达８５％以上，使用绿僵茵１．５×１０１３个／ｈｍ２孢子防治，效果可达７０％以上。     

针叶小爪螨药剂防治研究

本文研究了在不同时期使用不同化学药剂对针叶小爪螨进行防治的效果。结果表明:3月中旬用20％螨死净1000～2000倍液喷干枝,可杀死越冬卵50％左右;越冬卵孵化盛末期用18％的高渗氧化乐果30倍液或40％氧化乐果5～10倍液采用常规涂环或树干(枝)纵向涂药的方法,防治效果达95％以上;叶片上发生量较大时,采用多种药剂树体喷雾,防治效果也均达到95％以上。     

云杉线小卷蛾生物学特性及防治初报

云杉线小卷蛾系中国新纪录种。在甘肃渭源县１年发生１代，以卵在２～３年生枝条针叶上越冬；翌年５月上旬开始活动，孵化盛期为６月上、中旬，羽化盛期为７月下旬至８月上旬，其为害与环境条件密切相关。用２５％增效氧化乐果乳剂１０００倍液喷雾，防治幼虫效果达８５％；用１０％敌对或敌马烟剂防治成虫的效果达９８％。     

辽宁三种林业害螨生物学特性研究初报

本文报道了三种林业害螨，即棒毛小爪螨，柏小爪螨，云杉小爪螨的生物学特性。上述三种害螨均属蜱螨目叶螨科，是为害针叶树人工林的主要害螨之一。近年来在辽宁很多地区的油松、赤松、樟子松、落叶松人工林中大量发生，城市绿化的柏树也受到为害，造成针叶枯黄脱落，影响林木生长。三种害螨每年发生７￣９代不等，均以卵在树皮缝，芽鳞，果鳞等处越冬，适时采用４０％氧化乐果，５０％二溴磷乳剂或８０％敌敌畏喷洒，均可收到较好的     

黄色阿异Xiu生物学及防治研究

黄色阿异ＸｉｕＡｒｕａｎｏｉｄｅａｆｌａｖｅｓｃｅｎｓＣｈｅｎｅｔＷａｎｇ１所１代，７月以卵越夏，冬。翌年３月孵化开始为害，共６龄，５龄至成虫期最主要危害期，５月中旬以前是化防的最佳时期。     

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.