森林是怎样为社会主义建设服务的

一、林多雨多.我地区四个林区县(三江、融安、融水、金秀,以下同)与七个非林区县对比,平均年降雨量和降雨天数,林区县平均为1740.4毫米和178.5天,非林区县为1368.3毫米和156天,林区县比非林区县降雨量和降雨天数分别多27.2%和14.4%.二、抵制旱灾.以大旱的一九六三年为例,林区县降雨量和降雨天数平均每县为1429.6毫米和170.3天,非林区县为969.6毫米和135.7天,林区县比非林区县分别多47.4%和25.5%.三、蒸发量少.林区县平均年蒸发量为     

介绍三种贮藏柑橙的保鲜方法

<正> 柑橙贮藏保鲜对于延长柑橙市场的供应期限有着重要意义。广东化州橡胶研究所1985年采用冷库调温贮藏、地下库贮藏和自然室温贮藏三种方法进行柑橙贮藏保鲜试验,结果表明,自然室温三种柑橙四种药物处理的试验,共贮藏595千克,150天,平均好果率93.16％;地下库贮藏720千克,150天,平均好果率96.05%;人工冷库贮藏720千克,平均好果率98.27％。     

Bt乳剂防治马尾松毛虫试验初报

Bt乳剂是一种广谱微生物杀虫剂,属苏云金杆菌系列。用BT乳剂200ml/亩,防治越冬2～3龄马尾松毛虫,15天平均药效为78.39%。防治第一代3～4龄马尾松毛虫,7天平均药效为71.04%。BT乳剂有抑制下代马尾松毛虫繁殖量的作用,对寄生无效影响较少,经济成本低于白僵菌、赤眼蜂等生物制剂。     

舞毒蛾寄生天敌昆虫及其自然控制研究

通过采集舞毒蛾卵块、幼虫、蛹在实验室内培育,共发现舞毒蛾寄生性蝇类6种、寄生蜂类4科8种。其中,幼虫期寄生天敌有金小蜂科1种,即黑青小蜂Dibrachys cavus;广肩小蜂科2种,即粘虫广肩小蜂Eurytomaverticillata和Eurytoma sp.;以及茧蜂科3种,姬小蜂科2种和寄蝇类,平均寄生率12.89%。蛹期的寄生天敌有毛瓣奥蜉寄蝇Austrophorocera hirsuta、日本追寄蝇Exorista japonica、条纹追寄蝇Exorista fasciata等,平均寄生率是13.30%。卵期未发现任何寄生性天敌。从幼虫到蛹期,寄生性天敌平均可降低舞毒蛾种群数量22.17%。     

沙棘硬枝扦插不同处理方法试验研究

山西右玉县采用不同处理方法在蓝色塑料大棚内进行了沙棘硬枝扦插育苗试验。结果表明,清水浸泡插穗3～5天,生根率、平均根数和根长分别比对照提高11.11%、84.44%和326.67%;夜间草帘覆盖苗床,插穗可提早3～5天生根,生根率、平均根数和根长比对照提高16.86%、89.19%和87.50%;应用沙棘林腐殖土+草炭(7:3)和沙棘林腐殖土作基质扦插效果最好,生根率、平均根数和根长分别为95%～97%、4.7～5.0条和2.8～3.2cm。     

葡萄膨大剂试验研究

采用10种自配药剂对大粒六月紫、8611、无核白鸡心进行膨大化处理。大粒六月紫以Cc效果较好，坐果率提高66.2%，平均单粒重增加18.0%。8611以Bc效果为好，座果率提高331.6%，平均单粒重增加9.5%。果实纵径增长效果比横径突出，果实呈椭圆形或长圆形。成熟期提前5－6天。     

杉木迹地连栽(二栽)新技术研究

经22年试验,选育适宜杉木迹地连栽的无性系造林,从75个杉木无性系中选出开天13、B23-6、B44等6个杉木无性系,其中B23-6无性系造林8年生时,平均树高6.9 m,胸径9.3 cm,平均单株材积0.028 23 m3,比CK1(优良家系混合)平均树高增高32.6%,平均胸径增粗38.8%,单株材积增加121.6%。杉木伐桩贮藏大量养分,用于嫁接开天13杉木无性系,8年生时平均树高9.3 m,胸径11.4 cm,平均单株材积0.052 7 m3,比伐桩萌芽林平均树高增加17.7%,平均胸径增粗11.7%,平均单株材积增加41.2%,比开化二代种子园的种苗造林,平均树高增高12.0%,平均胸径增粗9.6%,平均单株材积增加31%。单位面积造林成本降低29.6%。     

湿地松高效低耗持续丰产采脂新技术的研究

通过对8种刺激剂和5种施药周期及3种割沟频率组合采脂技术的筛选,2年的采脂试验,取得的松脂产量数据经本底产量对比研究,以采用复方植物生长调节剂作刺激剂,12天为一刺激周期,割沟频率4天1刀为组合的采脂方法效果最好。与常法采脂比较:平均单株全年松脂总产量提高20%以上;单刀产脂量提高100%以上;割面消耗降低50%;采脂工劳动生产率提高66.6%;经济效益提高1倍以上。     

药用植物昆明山海棠插根繁殖试验

昆明山海棠根插总体平均成活率26.17%,插根长度对成活率无显著影响,插根粗度对成活率有显著影响。0.4~0.8？粗度插根成活率明显高于0.8~1.2？、1.2~2.0？粗度的插根,成活率依次为36.30%、24.44%、17.78%。插根第30天形成愈伤组织,第54天初始发芽。6月初至7月中下旬为萌发高峰期,萌发过程延续至9月中旬。1年生根插苗木平均高（茎长）35.9？,最高达126？;平均地径0.43？,最大0.9？;平均根数6.9条,根平均长度18.62？,根平均粗度0.25？。     

石梓育苗技术研究

石梓种壳骨质，透水性能差，播种前催芽处理可促进发芽。用浸晒法和石灰浆沤种法催芽的发芽率高达81%和84%，比对照分别提高16.3%和19.3%；温箱38-40℃湿沙催芽的发芽最快，比前两种方法提前8天，比对照提前14天。不同播种期的苗木合格率，6月为87.2%、7月为94.9%、8月仅为10.3%。大、中、小型子叶的芽苗，分别移植的苗木生长差异不显著，而混合移植对3种苗木生长有显著的影响，苗木平均合格率，分别移植比混合移植的高15.3%。文中还阐述了苗木生长规律、种子发芽前中午淋水、芽苗分床移植，以及施肥管理等有效的育苗技术措施。     

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.