板栗褐斑圆筒象生物学特性及其防治措施

褐斑圆筒象（Ma0cr0c0rynusplumbeusF0r－manek）隶属象虫科害虫。1992年皖南宣州市麻姑山林场发现其成虫危害栗叶，对板栗生长、产量影响较大。近几年我们对该虫生物学特性进行了观察，并开展防治，现将结果报导如下。1分布与危害资料报道该虫分布在云、贵、川等省，经调查我省栗产区均有分布，江苏、浙江等地也有危害。其成虫啃食栗叶仅留叶脉，造成栗树生长衰弱乃至减产。据近几年观察，重害年份虫株率100％，单株最高虫口528头，栗叶损失量60％以上，减产3～4成。2形态特征成虫体长4．5～6mm，体宽2～2．5mm，细长筒形，黑色。体及触角…     

黔阳结板栗优良无性系

黔阳结板栗最我省推广的优良农家品种，现已从中选育出83—01、83—02、83—06号三个优良无性系，据观察，丰产性能更好。结板栗9月下旬成熟，每公斤60—80粒，三个优系果枝平均着果1，4一2．0个，出籽率40—41％，籽重17—18．5克，每平方米冠幅平均产量0．7—0．8公斤以上。果实品质中上，耐贮藏。在9～17℃，湿度79—81％地下库藏60天，坏果率为17，1—18，3％，对照的油板栗为60．8％，储存180天．坏果率34—36％，油板栗为77％。子代测定，嫁接苗第三年70％挂果；第四年，平均单株产果0，34—0，43公斤；第五年，平均林产果1，68—2．1…     

高脂马尾松扦插苗与实生苗造林早期生长比较

通过对高脂马尾松扦插苗、实生苗进行造林试验，结果表明：造林后2～5年，两种林分平均保存率均达到95％以上；3、4年生时树高、胸径、单株材积差异极显著，4年生时扦插苗的幼林树高、胸径、冠幅、单株材积平均分别高于同龄实生苗的13．11％、24．95％、18．53％和69．81％，说明利用优良无性系繁殖扦插苗进行造林是可行的。     

杉木第二代种子园子代遗传变异及优良家系选择研究

来自广东省龙山林场杉木第二代种子园的39个自由授粉家系参加了1998年多点子代测定和2001年单点子代测定试验,结果表明：11年生子代测定林的树高、胸径、单株材积在家系和地点间差异达到极显著水平（P〈0．01）,8年生子代测定林生长性状的差异较小;家系平均树高、胸径、材积遗传力分别为0．24、0．26、0．30,主要生长性状受中等偏下的遗传力控制;第二代种子园材积遗传增益在1．88％～5．85％．其遗传增益和现实增产效果高于1．5代种子园,也高于初级种子园。对11年生多点子代测定林家系进行了丰产稳定性分析,选择出广谱丰产稳定家系5、8、17、19、23、26、28号,平均单株材积比群体均值提高3．39％;丰产家系3、7、15、21号和家系20、22、25号,分别适合龙山林场和曲江林场及相似立地条件地区限制性推广利用,平均单株材积比群体均值分别提高9．91％和4．89％;8年生单点子代测定林,以单株材积高于群体均值作为入选标准,有1、2、4、6、7、8、10、11、12、14、15、19等12个家系入选,平均单株材积比群体均值提高6．76％。     

人工释放花绒寄甲对光肩星天牛的控制效果

以城市行道树垂柳为对象,试验研究了释放花绒寄甲4～8a后对光肩星天牛的控制效果,结果表明,与未释放的对照林相比,释放花绒寄甲4～8a后可将光肩星天牛的危害株率由100％控制于23．46％,株均幼虫数由5头控制于2头;释放年份不同控制效果虽有差异,但差异不明显;释放花绒寄甲能够持续有效降低树木的受害株率、降低光肩星天牛幼虫数量。     

环境对皖西大别山皱鞘双条杉天牛发生的影响

皖西大别山林区4月月候气温在18．6～20．6℃时，皱鞘双条杉天牛Semanotus bifasciatus sinoauster (Gressitt)卵孵化率为74．74％～82．35％。通过抚育管理的纯林，每hm^2在3900株以下的8a～16a生林分，抽样林分平均种群密度在0．46头以下，有虫株率为0．33％～14．50％，未抚育管理的纯林种群密度每株在1．1头～1．61头、有虫株率为21．67％～26．83％。而混交林极少，甚至不发生。     

亟待转变经营方式的产业

1生产现状金寨板栗的发展从80年代初的零星栽植，至现在大面积栽植，板栗面积由1983年的2．3万亩，至1996年40．4万亩，占全县有林地面积的10％，是全县经济林面积的56％，居全省之首，板栗产量由1983年的8万kg，1995年增长到900万kg。板栗已成为金寨7．8万户、全区近12万农户举足轻重的产业。2存在问题去年由于天气影响，金寨板栗有近一半的栗园绝产，约16万亩栗园大幅度减产，通过调查分析，凡是嫁接后5年生以内尚未郁闭的板栗园，全部丰产丰收；凡在四旁四边栽植的零星分布的栗树丰产丰收；凡是栗粮间种或采取连年施肥，连年喷施“增产素…     

板栗防病杀虫增产剂在低丘栗园开发中的应用

在江苏仪征低丘综合治疗与开发研究试验区栗园扩大应用江苏省林科院研制出的板栗防病杀虫增产剂的结果表明：喷施该药剂后一般促进板栗子房发育，使坐果率提高，落苞和病苞减少，单位面积栗苞数增加。使板栗出实率、栗苞出粒率和单粒重明显增加，使板栗栗实病粒率和虫蛀率明显减少，从而提高了板栗样实的质量等级。对不同栗园和不同板栗品种均有显著增产效果，单位面积产量增产达30．3％－92．2％，平均增加产值达1684．1－4367．2元／hm^2，投效比达1：11．2－1：29．1。     

萧氏松茎象幼虫食性、危害及防治技术

萧氏松茎象幼虫在南岳衡山主要危害华山松，在寄主树干基部皮层和裸露的根皮层蛀食，造成大量流脂，导致生长衰弱，引起松墨天牛暴发；同时取食新鲜松脂，越冬后的幼虫仅靠取食新鲜松脂就能正常发育。幼虫只危害健康松树，不危害衰弱木、枯立木，说明其蛀食危害与松树能否分泌松脂有关。在被害松林内，单株幼虫数在0～6头之间。幼虫在有虫株之问分布较均匀，1头／株的占82．5％，平均为1．38头／株，且单株虫口密度与树干基部直径呈明显正相关。混交林和非松树林分能阻止该虫扩散。5—10月间在幼虫危害期和蛹期，采用人工清除幼虫和蛹的方法可有效控制该虫危害，而采用化学药剂防治该幼虫，效果不明显。     

尾叶桉无性系生长比较研究

对12个尾叶桉无性系的生长性状差异分析和比较结果表明：各性状在无性系间差异均极显著，各性状的无性系重复力75．24％～94．32％，单株重复力为43．18％～80．57％。冠幅的重复力最小，材积最大。5．5年生时共有4个无性系生长量超过总体家系平均值，生长最优的无性系平均单株材积达0．1684m^3，是最差无性系的253．78％，是平均值的58．38％，比最优对照U6无性系高79．33％。应用主成分分类方法，将无性系分成6类。速生型无性系较慢生型无性系的树高、胸径和材积分别高出30．40％、57、74％和221．64％，增产效果十分显著。     

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.