杉木主要经济性状多层次的遗传变异

借助于１０年生的杉木种子－家系两水平试验林,研究了杉木主要经济性状在多层次上的遗传变异规律,其主要结果如下;（１０在相同的研究性状上,通常家系内个体间的变异量〉种源间变异量〉种源内家系间的变异量;性状的遗传个体〉种源内家系〉家系内个体;不同变异层次的遗传改良潜力是不同的;通常种源－家系内个体－种源内家系;多层次联合选择获得最大析选择进展。（２）在相同的变异次上,杉木各研究性状具有各自不同的遗传改奶     

杉木地理种源长期选择效果研究

[目的]研究不同林龄的杉木地理种源生长状况的差异,筛选适宜于试验区发展的杉木优良种源,促进杉木种源水平的长期遗传改良。[方法]利用1981年营造的杉木种源试验林在5、10、31年生时的测定材料,分析不同种源主要生长性状在不同林龄的遗传参数变异规律,利用早晚相关和聚类分析对优良种源长期选择效果进行评价。[结果]不同林龄的杉木胸径、树高和单株材积在种源间均存在极显著的差异,31年生时最大种源的各性状值较最小种源的各性状分别高75.86%,48.55%,263.76%;杉木在种源间的变异存在明显的地理变异模式,以纬向变异为主,由南向北,杉木的生长量先增大后减小,即我国西南和东南部种源生长较好。参试杉木种源不同林龄时各性状的遗传力为0.750～0.875,说明各性状受较高水平的遗传控制;胸径、树高和单株材积在不同林龄间表型相关和秩相关均呈极显著的正相关,认为杉木早期选择宜在10年生左右;从169个参试种源中筛选出29个生长较快速的种源,大部分种源来自福建省,还包含贵州、广西和湖南等地的种源,其中,生长最好的是福建崇安、顺昌、尤溪等福建北部种源,其胸径、树高和单株材积的遗传增益分别达到23.21%～31.45%、15.60%～20.19%、59.94%～89.97%。[结论]早期选择的年龄对缩短杉木育种周期影响明显,在10年生选择更有利于提高杉木遗传改良的效率,从31年生杉木成熟林中选择出的29个优良种源较当地种源有较大增幅,适宜在江西省及周边地区推广。     

杉木种源－林分－家系遗传变异研究

运用杉木种源、林分、家系三水平联合试验６年生林分的生长性状和物候观测资料，研究其遗传变异信息。结果显示，种源间、种源内林分间、林分内单株间的胸径、树高、材积都存在极显著差异；在三水平任何层次上的生长性状选择都是有效的，但各层次变异差别很大，其方差分量排序依次为：种源＞林分＞家系，种源、林分、单株材积遗传力分别为０．８４８、０．３９９、０．２３２；选择层次依次是种源、林分、单株。种源（群体）是较稳定的遗传单位，但种源内林分间差异显著，可进一步探讨遗传学上的杉木种源单位的确切范围。种子发芽率、物候因子分析表明，种源间差异显著，林分间差异不显著。     

杉木地理种源不同林龄生长变异及选择

【目的】通过对33年生杉木种源试验林生长性状的调查研究,了解杉木种源主要生长性状的遗传变异及地理变异模式,对早期选择的效果进行检验,确定杉木种源早期选择的适宜年龄,并为试验区选择适生的优良种源。【方法】以1981年在广西柳州营造的杉木全分布区种源试验林为研究对象,参试种源为199个,在5、6、8、12和33年生时测定每木胸径和树高,分析不同种源主要生长性状在不同林龄的遗传变异规律,采用趋势面技术分析杉木地理变异规律,采用早晚相关确定早期选择的林龄范围,利用聚类分析对优良种源长期选择效果进行评价。【结果】不同生长时期杉木种源的胸径、树高和材积在种源间的差异均达到极显著水平(P0. 01);参试杉木种源的胸径、树高和材积的遗传力达到0. 35～0. 76,随着林龄的增长,各性状的遗传力呈现上升并逐渐稳定的趋势;杉木种源间存在明显的地理变异规律,胸径和树高生长地理变异模式均表现为双向渐变,经度方向呈现不显著的正向变异,纬度方向上呈现先增加后减小的趋势且变幅较大;种源早期选择的研究表明在6～12年生时选择能包含决选69%～74%的种源;从199个参试种源中筛选出42个生长较快速的种源,其胸径、树高和材积分别达到24. 04cm、15. 31 m和0. 31 m3,与广西当地种源相比平均胸径、树高和材积分别增加15. 70%、11. 13%、40. 17%,平均遗传增益分别达到10. 36%、8. 66%和31. 65%。【结论】杉木种源在不同林龄生长差异极显著,且主要生长性状的遗传力呈现上升并逐渐稳定的趋势。早期选择在6～12年生时更有利于提高杉木遗传改良的效率。42个生长优良的杉木种源被选择出来,与广西当地种源相比有较大生长增幅,适宜在广西壮族自治区及周边地区造林推广。     

杉木种源—林分—家系遗传变异研究

运用杉木种源，林分，家系三水平联合试验６年生林分的生长性状和物候观测资料，研究其遗传变异信息，结果显示，种源间，种源内林分间，林分内单株间的胸径，树高，材积都存在极显著差异，在三水平任何层次上的生长性状选择都是有效的，但各层次变异差别很大，其方差分量排序依次为，种源〉林分〉家系，种源，林分，单株材积遗传力分别为０．８４８，０．３９９，０．２３２；选择层次依次是种源，林分，单株，种源（群体）的较稳定     

苏南低山丘陵杉木造林优良种源选择试验

杉木地理种源群体间存在着明显的性状变异．利用变异选择出广西融水、湖南江华、贵州锦屏、广东乐昌、江西全南、湖南会同等优良种源，可使苏南低山丘陵地区杉木林蓄积量增加２０％以上；广西贺县、广西浦北、广东信宜、江西铜鼓等初期生长快。对结实量多的种源，可用于短轮伐小径材、椽材作业，以利用其早期的增产潜力．     

苏南低山丘陵杉木造林优良种源选择试验

杉木地理种源群体间存在着明显的性状变异，利用变异选择出广西融水，湖南江华，贵州锦屏，广东乐昌，江西全南，湖南会同等优良种源，可使苏南低山丘陵地区杉木林蓄积量增加２０％以上；广西贺县，广西浦北，广东信宜，江西铜鼓等初期生长快对结实量多的种源，可用于短轮伐小径材，橡材作业，以春早期的增产潜力。     

种源试验要求的家系和子代数目

在种源试验中,要可靠评价每个种源的平均表现时,是使种源平均数标准差最小时来确定家系和子代数目的。该标准差是以参试家系间和家系内的变异来计算的。计算结果表明,在性状遗传力低时,每一种源需测200个子代数;如果性状遗传力高时,只100个就够了。每个试验点的每个种源应包括5～10个家系中的100～200个子代数。除非种源试验是为了将来选择种群,一般种源试验,很少超过10个家系的。     

马尾松造纸材种源选择

在南、中、北亚热带地区三片九年生马尾松种源试验林中(广西南宁、江西安福、浙江鄞县),采集9个代表性种源试样,测试28项包括木材构造、物理和化学的性状,进行种源间比较选择,结果是:①经试验点内及多点方差分析,各性状种源间差异远大于种源内个体间差异,且种源与试验点间存在互作。②主要造纸经济性状(管胞宽、长宽比、双壁厚、腔径和壁腔比等)遗传力估值均大于0.6,受强度的遗传控制。③材性与生长性状间相关分析表明,在马尾松速生地区作高、径性状的正向选择会导致种源或个体的管胞长宽比、晚材率和壁腔比下降,管胞宽度及腔径增大,这为间接选择提供依据。④取与造纸性能关系紧密的11项木材性状,综合选择出高州、宁明、吉安和德江等优良种源。     

9年生枫香种源变异及优良种源选择

研究枫香种源间性状差异及地理变异规律,并进行优良种源选择,为枫香良种选育和生产应用提供理论依据。以14个省份22个枫香种源为研究材料,选取生长性状指标和形质指标,进行种源间差异性分析,广义遗传力估算、地理变异规律研究,采用多目标决策法进行优良种源选择等。结果表明:枫香种源间在胸径、树高、材积、第一枝下高、冠幅和通直度6个性状上均存在极显著差异(P 0.01),种源间各性状的遗传变异系数为10.21%～36.16%,广义遗传力为0.42～0.83,其中以树高的广义遗传力最大。相关性分析结果表明,枝下高越高,冠幅越大,树干越通直,其生长越优良;材积表现出显著的纬向变异趋势,呈负相关关系(P 0.01)。选出优良种源6个,入选的优良种源平均胸径、树高、材积、冠幅和通直度分别大于总体均值的5.25%、8.30%、16.51%、1.26%和2.11%。选出的优良种源对调种造林、杂交育种、"边选边育"等工作具有重要的参考价值。     

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.