漳平五一林场全国杉木优良家系区域试验

本研究对全国不同区域１２１个杉木优良家系９年生材积生长量进行统计分析表明：家系平均遗传力高，家系间生长差异极显著，家系遗传变异系数大，家系方差分量占总分量１３．２％；有７６个家系材积生长量超过我场初级种子园后代，６３个家系材积生长量超过洋口初级种子园后代，２０个家系材积生长量超过我省优良家系６４２１号，其材积增益比我场种子园后代大２５．４％─６５．６％。     

杉木优良家系遗传稳定性的研究

通过对１４个省共１１２个优良家系的区域性试验，测定杉木优良家系遗传稳定性和生长潜力的研究，结果表明：对于杉木的材积生长，其家系间、地点间、家系×地点间交互效应均存在极为显著的差异，家系遗传力为０．７３５６。根据遗传稳定性参数和家系材积生长情况，选出８个优良速生家系，平均材积比杉木１．５代种子园遗传增益达１７％。各地点分别选出８个最速生家系，其材积增益为１１％─５１％，增产效果十分明显。     

长白落叶松优良家系选择的研究

抚顺县哈达部省合建林木良种基地，于１９８５～１９８６年共营造长白落叶松１９个家系的子代测定林。经１９９４年秋调查分析，共选出１２个优良家系。其优良家系的平均遗传力，树高为０．７８４，胸径为０．６７８，材积为０．７１０；平均遗传增益，树高为９．８％，胸径为１０．０％，材积为２６．２％。实现材积增益超过对照１５９．３％，超过家系总平均值的３７．５％。     

邓恩桉6个种源的28个家系子代测定初报

来自澳大利亚两个州的６个种源２８个家系子代测定５．５年生结果表明：参试种源间树高、胸径、材积、冠幅及枝下高生长无显著差异，而家系间生长存在显著、极显著差异．参试种源家系生长量与原产地纬度、经度、海拔及雨量均相关不紧密；邓恩桉具有中等遗传力，经比较分析，初步选出Ｄ９、Ｄ３９、Ｄ３８、Ｄ２、Ｄ２６、Ｄ２５等６个家系为优良家系，其材积平均比参试家系平均增益２１．３％，比对照柳桉的材积增益２８１．６８％．邓恩桉可在桂中及相应地区一带推广栽培．     

黄冕林场大叶栎不同种源/家系子代林的测定结果研究

在位于广西柳州市的黄冕林场进行了大叶栎9个种源、51个家系的子代测试试验。结果表明，在其子代试验林的3年生幼林期，不同种源、家系大叶栎林木的树高、胸径、单株材积等生长性状存在显著差异，据此采用综合评定法从大叶栎种源中初选出14个大叶栎优良家系。所初选的这14个大叶栎优良家系，其3年生子代幼林林木的3个生长性状与最差家系相比，平均树高增长率为23．61％～3．3．33％，平均胸径增长率为37．15％-49．54％，单株材积增长率为124．4-5％～177．84％。     

长白落叶松优良家系选择的研究

对24年生长白落叶松自由授粉家系子代测定林的研究结果表明，胸径、树高、材积3个性状在家系间都存在显著差异，通过对17个家系的生长性状分析，筛选出了170、120、501、322、153、274六个生长性状优良的家系，其胸径、树高、材积平均大于对照3．83％、7．23％、11．67％。     

福建柏优良种源和家系优树选择研究

通过福建柏19个地理种源和48个家系造林试验,初步选择出10个优良种源和14个家系,其材积遗传增益分别为16．09％～88．70％、15．19％～184．80％。参照福建柏优树国家标准,在优良种源和家系林分中,选择出优树179株,其材积遗传增益比优良种源和家系分别提高17．45％～122．51％、3．30％～191．69％。     

尾叶桉二代测定林家系的综合评选

对49个家系的尾叶桉测定林各年度生长性状进行分析与遗传评估,结果表明：各年度树高、胸径和材积生长量在家系间存在极显著差异;分枝、干形和保存率在家系间存在显著差异;树高、胸径、单株材积、保存率的累积贡献率达95．45％,此4因子是综合评定家系时采用的;以家系群体平均选择指数I0为基准,两种选择标准下的家系材积增益,3年生时为7．63％～15．80％,4年生时为3．92％～10．39％,5年生时为6．08％～23．53％;以选择指数为指标,5年生时人选的5个优良家系是：109,113,66,81和100号。     

津巴布韦火炬松遗传资源林的评价与选择

研究了由津巴布韦引入的以家系为代表的火炬松遗传资源50个号的苗期与幼林生长表现。结果表明，5年生的单株材积差异显著，有14个系（含3个对照）与最劣系有显著差异，可列为优系。在30％的家系入选率下，配合选择的材积遗传增益为3．1％，入选优株148株；1、3年生树高与材积的早期相关为较显著或极显著，故早期试验林可测定树高为主，以减少工作量；还比较了3种统计分析方法应用效果和选留前1／3和淘汰后1／3，5年生时优系的保持率和丢失率，并主张早期选择以淘汰劣系，以指导育种与生产工作为好。     

湿地松单亲子代遗传变异分析

来自４个省份，５个引种群体的３０个优树单亲子代测定１５年结果表明：参试家系在材积、胸径和对褐斑病感病性上存在极显著的遗传差异。其中福建南屿家系群体生长快．树皮薄，侧枝数多；江苏和南京家系生长最差；江西家系平均抗褐斑病能力最强。通过多重比较，初步筛选出ＦＪＮＹ—００３．ＪＸＪＡ—０７７，ＡＨＪＸ—００１和ＪＸＪＡ—０８７等４个家系，它们材积平均生长比ＣＫ快３８．４％，平均遗传增益为１７．０６％；胸径平均遗传增益为５．１２％，感病性降低５．４３％。文中对性状间相关及其遗传参数也作了分析。     

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.