四旁树抽样回归调查

为在森林资源清查工作中搞好平原湖区的四旁植树调查,我们根据江苏省以生产队为总体单元进行抽样调查的经验,于去年八至九月,在江汉平原的沔阳县汉江公社进行了试点。试点以公社为总体,生产队为总体单元进行抽样     

蒙古栎橡实蛋白的提取工艺研究

利用酶解法对橡实蛋白进行提取,结合单因素及正交试验方法进行分析,对蒙古栎橡实蛋白的提取工艺进行研究。结果表明,碱性蛋白酶为橡实蛋白提取的适宜水解酶;单因素试验结果显示酶添加量为1.4%,pH值为11,酶解温度50℃,时间3 h为适宜的提取条件;由正交试验结果可知,橡实蛋白最优提取工艺:酶添加量为1.4%,pH值为11.5,酶解温度50℃,时间2.5 h。在此条件下进行验证试验,3组平行试验的提取率均值为56.13%。     

四旁树抽样回归调查

为在森林资源清查工作中搞好平原湖区的四旁植树调查,我们根据江苏省以生产队为总体单元进行抽样调查的经验,于去年八至九月,在江汉平原的沔阳县汉江公社进行了试点。试点以公社为总体,生产队为总体单元进行抽样回归调查。为验证调查结果,将全公社树木株数、材积进行了实测,结果证明效果良好,理论精度达81.6％～96.4％,实际精度达91.8％～99.8％基本方法在县委的统一领导下,首先充分发动群     

黑龙江省密山林场风电场设计可行性研究

黑龙江省密山林场（柳毛）风电场位于黑龙江省密山市东南部,兴凯湖以北。密山地势西北高、东南低,北部为完达山脉,南部为长白山余脉,中部为穆棱河冲积平原,海拔在65m～683m之间。本文将对柳毛风电场的风能资源进行分析、对风电机组的选型布置以及风电场的发电量进行估算,目的是为柳毛风电场的设计进行可行性分析。     

伐木楔的改进及安全作业

该事业所的年木材生产任务为34,000m~3,其中夏山伐区为8,000m~3,冬山伐区为28,000m~3,以提高生产率及无伤亡事故为目标进行组织生产。上述两伐区冬季积雪量大,林地下均倾斜度为25度,系大径木占有相当比例的天然林,故以择伐为主进行生产。冬季树木冻结,如用购买的合成树脂树楔,易于回弹滑动,使用困难。为消除或防止树楔滑动而进行了研究,现将试验经过介绍如下:     

木麻黄优树子代测定试验初报

对12个木麻黄优树子代进行田间试验比较,从中选出最优的单株进行早期育苗造林观察测试。幼林仅半年生,主要从树高生长指标进行初期评价。幼树生长最快的为东里5号,平均高75 cm,标准差为22.6,生长最均匀标准差最小的为南山11号,平均树高71 cm,标准差16.9。     

YP_(2.0)-A型遥控跑车减速机构仿真及优化

以YP2.0-A型遥控跑车的减速机构为研究对象,应用HyperMesh中的ANSYS模块对其进行3D网格划分,并对其进行接触静力学仿真分析。结果表明:该构件的最大工作应力为123.2 MPa,满足材料的强度条件和工作要求;并进行优化设计,为进一步结构设计提供依据。     

野生花脸香蘑的分离鉴定及生物学特性初探

采用组织分离法对采集的一株野生大型真菌花脸香蘑[Lepista sordida(Fr.) Singer]子实体进行菌种分离,结合形态鉴定法及ITS分子序列鉴定法对菌种进行了鉴定,并对该菌种菌丝生物学特性进行了初步研究。结果表明,分离株rDNA ITS片段长度为651 bp,测序结果登录NCBI与GenBank中已知菌种进行BLAST比对,序列相似性在97%～100%之间,下载相似高的ITS序列,用Clustal W进行序列比对,MEGA 2.0软件构建系统树,结合形态特征,鉴定分离菌种为花脸香蘑纯菌种。生物学特性研究结果表明:适宜菌丝生长的碳源为可溶性淀粉,适宜的氮源为硝酸铵,适宜的pH值为7.0,菌丝最适温度为25℃。     

提高板栗产量的几种试验方法

庐江县是我省板栗主产区之一,平均亩产约90kg。为提高板栗产量,在不同的立地条件的地方设立标准地,试验于2007年进行,树龄为8年生。通过多种措施进行对比和处理,对影响板栗的几项主要条件进行试验。     

密云水库集水区(北京境内)水源保护林最优林种结构的研究

运用层次分析法对密云水库集水区 (北京境内 )水源保护林最优林种结构进行分析 ,并结合实际情况进行了适当的人为调整。结果表明 ,该区水源保护林最优林种结构为 :针叶林为 19.4 % ,阔叶林为2 9 .5% ,混交林为 2 3.9% ,灌木林为2 0 % ,经济林为 7.2 %     

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.