福建武夷山木荚红豆树木材物理力学性质研究

对福建武夷山木荚红豆树木材物理力学性质的测定和分析结果表明：福建武夷山木荚红豆树木材的气干密度为0．627g／cm2,属中等,较福建永安木荚红豆树木材的气干密度大;体积干缩系数为0．486,差异干缩为1．89,干缩性属中等,小于福建永安木荚红豆树;顺纹抗压强度和抗弯强度分别为51．93MPa和99．64MPa,综合强度为中等,大于福建永安木荚红豆树。该研究结果解决了木英红豆树营林和木材利用上的一个基础性问题。     

卷荚相思实生苗与扦插苗造林初期效果比较

通过对比卷荚相思实生苗和扦插苗造林的生长情况,经2年调查,结果表明:卷荚相思的实生苗和扦插苗的造林保存率均达到91%以上,2年生的扦插苗平均树高和胸径、单株蓄积量、单位面积蓄积量分别比实生苗提高10.4%、13.8%、38.9%、38.3%,没有发现寒害、风害和病虫害,说明卷荚相思适应晋江市的气候和土壤,可以在晋江市种植。2年生的实生苗与扦插苗的优势木树高和胸径分别比平均木提高16.7%、45.2%与17.7%、41.4%,说明林分生长还有很大的潜力,可以通过筛选优树的方式,采用扦插繁殖技术培育卷荚相思优良无性系来促进林木的速生丰产。     

鄂西红豆树、木荚红豆树早期生长差异比较

通过对鄂西红豆树、木荚红豆树的苗期生长量试验观测,以及对比造林试验,结果表明:鄂西红豆树的生长速度比木荚红豆树快,1 a生苗木的平均地径和平均苗高分别增长了58.8%、26.7%.鄂西红豆树的造林成活率可达92%以上,木荚红豆树即较低.在早期生长中,鄂西红豆树的生长速度较木荚红豆树快,地径生长量与幼树抽梢的增长率分别达33.9%和29.5%.鄂西红豆树的生长分化比木荚红豆树大,鄂西红豆树单株最大抽梢量可达141 cm,具有速生潜能.地径对鄂西红豆树幼树生长的影响程度大于苗高.     

福建天然木荚红豆分布和生长过程研究

通过对武夷山市星村镇四新采育场63年生天然木荚红豆树进行按树干解析区分段,对其直径、树高、材积等因子的变化规律和生长过程进行了分析。结果表明:63年生木荚红豆天然群落平均木的树高生长高峰期在第18年左右,直径生长高峰期在第33年左右,材积和生物量数量成熟应当在58年以后。     

疏伐——营建母树林的重要技术措施

营建母树林的目的主要是生产品质优良的林木种子。母树林的营建形式分为改建型和专建型2种类型。在天然林或人工林中选择优良林分,通过疏伐留优去劣改建而成的为改建型母树林;利用优良种子培育实生苗,选择优势苗所营建的母树林为专建型母树林。在林木良种生产中,营建型母树林技术简单、投资少、建设快、结实早,能在较短时间内获得数量较多的良种,供应大面积植树造林。目前,改建型母树林已成为我省林木良种的主要生产途径之一。疏伐,是营建改建型母树林的一项重要技术措施,必须予以足够的重视。一、疏伐的依据一是森林在生长发育过程中,会发…     

翅荚木优质苗木培育技术

翅荚木树干通直圆满,生长快,是优质造纸材原料,是营造短周期工业用材原料林的重要树种之一。本文针对生产上存在的翅荚木优质苗木培育等技术问题,对翅荚木裸根苗、容器苗培育过程中种子收集保存、苗圃地选择、催芽、播种、苗期管理等各个环节的技术措施进行综合,以期为培育翅荚木优质苗木提供技术支撑。     

福建柏等4个珍贵树种人工纯林涵养水源研究

珍贵人工纯林福建柏、楠木、木荚红豆和青钩栲其涵养水源功能存在较大差异,其持水量表现为：木荚红豆〉福建柏〉青钩栲〉楠木。不同林分各层次持水量均表现为：土壤层〉林冠枝叶层〉凋落物层〉林下植被层,其中土壤层是涵养水源的主要场所。     

尖峰岭热带山地雨林豆科树木对邻体树种的影响

目的 分析海南典型热带山地雨林分布区域尖峰岭60 hm2大样地内豆科树种对邻体树木的影响,并探讨其可能的影响机制。 方法 利用尖峰岭60 hm2大样地的2012年和2018年2次调查数据,对样地内7种豆科树木的邻体非豆科树木的多度、丰富度和存活率进行比较分析。 结果 2次调查期间,7种豆科树木的邻体多度和丰富度无显著变化。与非豆科树木相比,软荚红豆(Ormosia semicastrata Hance)、猴耳环(Archidendron clypearia (Jack) I.C.Nielsen)和亮叶猴耳环(A. lucidum (Benth.) Nielsen)具有较高的邻体多度和丰富度,而肥荚红豆(O. fordiana Oliv.)、木荚红豆(O. xylocarpa Chun ex L. Chen)、长脐红豆(O. blansae Drake)和薄叶猴耳环(A. utile Chun et How)具有较低的邻体多度和丰富度。软荚红豆、肥荚红豆和猴耳环具有较高的邻体树木的存活率,而长脐红豆、薄叶猴耳环、亮叶猴耳环和木荚红豆具有较低的邻体树木的存活率;7种豆科树木对邻体多度、丰富度的影响与其叶片氮含量和固氮能力无显著相关关系,但邻体距离为4 m的豆科树木邻体存活率与叶片氮含量有显著相关关系。 结论 总体上,不同豆科树木对邻体的影响不尽相同,软荚红豆更倾向于对邻体产生有利作用,薄叶猴耳环和木荚红豆对邻体产生抑制作用,而其它4种豆科树木对邻体的多度、丰富度和存活率的影响不一致。     

板栗实生苗培育技术

板栗主要用实生育苗法和嫁接育苗法繁殖。用实生苗培育,具有植株生长健壮、生命力强、适应性广、寿命长等优点,且实生苗培育技术简单易掌握。培育优质的实生苗,需要把住"三关":种子的采收储藏关、播种整地关、苗木管理关。     

木荚红豆育苗技术研究

采用随机区组设计木荚红豆种子不同采收期、播种方式、播种期、种子处理、种源对比研究。结果表明:不同采收期木荚红豆种子产量和质量存在差异,本地区种子采收期以11月以后为好;播种方式对苗木质量和产量无明显差异,但条播节省种子,便于锄草、施肥;播种期对苗木质量和产量存在差异,以3月后为好;种子处理对种子的发芽率、成活率无明显差异,但经机械处理种皮的种子出苗早且整齐;不同种源对单株生物量有所差异,但不影响苗木质量。     

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.