杉木福建柏混交林效益研究

通过对杉木福建柏混交林中单株生物量组成、土壤团粒组成、土壤孔隙和水分状况的研究分析， 结果表明： 混交林中杉木每ｈｍ ２ 蓄积量是杉木纯林的１６９ 倍， 细根量是杉木纯林的１５ 倍； 与纯林相比， 混交林中０～２０ｃｍ 土层＞ ０２５ｍ ｍ 水稳性团聚体高出９０１％ ； 结构体破坏率低１５８２％ ； 有机质和水解性 Ｎ 含量分别高０２４５％ 和１３１×１０－ ６； 毛管孔隙、非毛管孔隙、总孔隙高００９％ 、０９１％ 、１００％ ， 土壤容重低００５７ｇｃｍ － ３； 最大持水量、最小持水量、毛管持水量分别高３００％ 、３５０％ 、２０４％ ； 混交林４０ｃｍ 土层含水量也比纯林大１５５ｔ·ｈｍ － ２。由于混交林的结构较为合理，能一定程度改善土壤理化性质、提高林分生产力，是一种值得推广的造林模式。     

诱发桃形李煤污病的主导因子和防治方法

诱发桃形李煤污的主导因子是梨园蚧危害，该虫在浙江浦江１年３代，以受精雌成虫越冬。防治方法：２月中下旬，用３￣５度石硫合剂全面喷洒；４月中下旬，５０％杀螟松８００￣１０００倍液喷洒；６月中下旬，５０％甲基托布津０００倍液喷洒；１１月份，５０％久效膦６￣１０倍涂干。     

双体免充气日光温室的研制与应用

日光温室是在现代加温温室的基础上发展起来的节能型简易园艺栽培设施。由于高跨比小，后坡投影大，透光量不足，有效空间较小，难以满足花卉等高经济性作物大规模工厂化周年高效生产之需求。双体免充气日光温室是在综合多种优化模型分析的基础上提出来的。它在后墙上直接支撑双体免充气可拆式全透光整体曲面结构，其基本参数为跨度５ｍ，脊高２５ｍ，高跨比０５０，后墙高１８ｍ，后坡长１９ｍ，后坡仰角２２°，后坡投影为零，前坡１ｍ处的垂直高度１９ｍ，剖面截面积６４６ｍ２。对照试验表明：双体免充气型无明显的弱光胁地；在不覆草帘的冬季，早晨６时和中午１２时的最高温度分别比对照高２℃和６２℃；夏季５０％遮荫后，室内各点平均温度低于对照３℃；冬季保温效果则更为显著，大于８℃的有效积温分别是鞍山Ⅱ型和室外的１５倍和５３倍；秋、春两季切花月季栽培试验表明，鲜切花的产量和质量也明显高于对照，尤其是早春的盲枝发生率仅为对照的４０％。     

龙眼扦插育苗及丰产栽培技术研究

采用文中所介绍的技术，龙眼扦插４０天后即产生愈伤组织，愈合率达８６６％；６０～９０天大量生根，生根率达８７２％，成活率达７４５％；９０天后即可进行苗地移栽，成活率达９０５％。１年生苗高６０～１５０ｃｍ，地径０６～１５ｃｍ，此时即可出圃定植。２～３年挂果，４年进入丰产期，丰产效果显著。     

郝家流域针阔带状混交林效应观测

通过对郝家流域内３种混交林（油松×山毛桃、油松×沙棘、樟子松×沙棘）的综合因子进行调查，结果表明，混交林的枯枝落叶量分别是油松纯林的１５倍、３２倍、２７倍；林分总持水量分别是油松纯林的３３倍、８９倍、６４倍。由各树种１０年生长进程可以看出，樟子松×沙棘、油松×山毛桃的混交效果较好。     

巨尾桉无性系山地引种造林效果的研究

通过对引进巨尾桉无性系与巨桉、尾叶桉进行山地造林试验３年的研究结果表明,巨尾桉无性系不仅能适宜本地区山地栽培,而且生长快,３年生平均树高１２１ｍ,胸径１２３ｃｍ,单株带皮材积００７２８ｍ３,去皮材积００５７４ｍ３,比尾叶桉分别增长２３５％、２８１％、９２１％和１４０２％,比巨桉分别增长１３１％、１９４％、５６６％和５１５％。它还具有树干通直圆满、树皮较薄、冠径比小、出材率高、丰产性好等特点,可以大面积发展,并总结出栽培上的关键技术。     

神灯白掌组织培养快繁技术

以神灯白掌顶芽或茎段作为外植体,消毒后接种在培养基（１）：ＭＳ＋ＢＡ１０＋ＮＡＡ０１＋３％蔗糖,培养３０ｄ。将无菌材料转接在新配制的培养基（１）上,３０ｄ转接１次,如此反复继代,年繁殖系数达３６。生根培养采用培养基（２）：１／２ＭＳ＋ＩＢＡ０８＋１５％蔗糖＋００２％活性炭。瓶内平均发根率达９８％以上,温室内移栽平均成活率达９５％以上。     

自制生根剂三法

果树、花木繁殖方法有多种，用枝条扦插较为常见，用枝条扦插常使用生根激素（如萘乙酸等）处理，以提高成活率。这种药物较难买，不便急用。下面介绍三种可以自制的生根剂，供选用。１柳枝浸液　取筷子粗的柳枝数条（多少视需要量定），去其叶片，剪成３５厘米～７厘米长的若干小段，加适量清水浸泡１０天左右，树枝与水重量比大约为１∶１５～２，即１千克树枝用１５千克～２千克水浸泡，以滤液浸插穗５小时～６小时，然后扦插，处理后的插穗可提前７～１０天生根，成活率高，生长健壮。２糖水液　用蔗糖和沸水配成５％或１０％…     

3种粉剂防治鞭角华扁叶蜂幼虫药效试验研究

选用２．５％甲基对硫磷，９０％灭幼脲Ⅲ号原粉和３％敌死蜱，分别用陶土稀释５种浓度防治鞭角华扁叶蜂１－６龄幼虫，试验结果表明，７２ｈ死亡率，用２－８倍陶土稀释的２．５％甲基对硫磷达８７．６％～９７．９％，用２５－２５０倍陶土稀释的９０％灭幼脲Ⅲ号原粉达８５．６％－９７．１％，用２－８倍陶土稀释的３％敌死蜱粉剂达８５．４％－９９．２％，２．５％甲基对硫磷，９０％灭幼脲防治成本分别为２１．６５－２３．５     

苹果果形剂应用试验初报

对苹果进行苹果果型剂处理多点试验结果表明：苹果盛花未期喷施１５０—２００倍苹果果型剂，Ⅰ类果达３０％—４５５％，Ⅰ、Ⅱ类果达６２９％—８１５％；果形指数在０９５以上，最大值１２；处理果果个增大，呈园锥形，着色均匀，色泽浓红。应用果形剂是生产高档优质果品的重要技术措施之一。     

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。     

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.     

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.     

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.