云南松优良种源生长量早期选择的研究

通过４１个云南松种源生长差异性，高生长遗传力及幼，成龄相关分析，初步揭示了生长量各年度的早晚期相关性，联系性和规律性，表明从第９年开始选择云南松优良种源的时机已经成熟，在５－６个位次以下的波动稳定率为８０．５％，排名前１０倍中有６个云南松优良种源进入最佳早期选择范围。     

云南松种源、林分和家系苗高生长的遗传变异研究

在云南松种源区划的基础上，评选出１１个产地，２４个林分，３２８个自由授粉的优良家系，在昆明双龙、蒙自芷村、祥云清华洞３个测试点上进行３水平的联合栽培测定，从幼苗的生长量表明，云南松的变异是丰富的，每一个选择层次上都可获得一定的遗传增益。它们的增益是：种源３０％～１１０％，林分１１０％～１１４％，家系１６２％～１９５６％。在云南松的遗传改良中，应有效地利用每一选择层次上的增益。综合利用多层次的变异     

云南松种源苗期地理变异的研究

从云南松自然分布区的不同生态区,不同经纬度,不同海拔高度和不同江河流域共收到各地的代表种源149个。选择了水热条件有明显分异的11个裁培点,同步进行裁培对比试验。3年的试验材料证实,不同种源苗期生长差异是极显著的。表现好的种源高生长超过对照20.5～200.6％,径生长超过12.9～103％,优劣种源间差异更为显著。通过分析,初步掌握了云南松的一些地理变异规律;得出种源内各性状间彼此存在一定的相关关系。为云南松种源选择和早期鉴定提供了技术依据。     

杉木优良种源家系选择

根据杉木地理种源试验和家系选择研究成果,从优良种源区直接引进经鉴定的优良家系组成选育群体,在江苏省句容市３个试点进行测定,优中选优。６ａ研究结果表明,家系间生长,适应性,抗病（炭疽病）性与结实性有显著的遗传差异。高径比、尖削度等干形指标和侧枝粗、林分整齐度等性状未见明显差异。家系选择具有较高的潜力和明显的增产效果。经综合坐标法选出亚林１、亚林２、湘１、湘２、林朵６、林朵７、林朵８、林朵１９、林朵２５等９个综合性状优良的初选家系,比生产上现行推广的广西融水优良种源杉木幼林（５ａ生）材积分别增加４９１％～２００１％（１２ｍ中等立地）;２８３％～１６０２％（１０ｍ较差立地）;１６４％～３７５％（１４ｍ优良立地     

白马河林场云南松天然林改建母树林效果初析

利用评选出的云南松优良林分改建母树林，是充分挖掘现有云南松优良种质资源，获取良种的一条经济有效的途径。本文对永仁县白马河林场云南松天然优良林分改建母树林的技术措施和母树林的概况作了介绍，并对改建效果进行了初步分析。改建后的母树林树干通直度为Ⅰ级的比率由６９％提高到９６９９％，木质纹理扭率由１５３８％下降为６０％，种子千粒重提高２ｇ～３ｇ，３年生子代林树高生长量比对照提高３９２％。由此看出母树林改建效果良好；所采用的技术方法对云南松群体选择改良具有示范意义和推广价值，对其他一些松科树种群体选择和母树林改建也有一定借鉴作用。     

滇西云南松母树林单株半同胞子代测定

１９９０ 年在腾冲古永林场对云南松母树林５ 个种源 （ 含对照） 的８１ 个家系采用９ ×９ 平衡格子设计展开试验。通过７ 年的试验表明： 母树林各家系和种源间存在着显著的差异， 生长量大于对照的有２１ 个家系， 木纹理扭转度小于对照的有６４ 个家系。滇西母树林的子代具有生长快、木纹理扭转度小的特点， 参试的２０ 个家系的子代其 树高、胸径、木纹理扭转度、分枝数、冠幅、松针束数和松针长度分 别超过对照３０９９ ％ 、３１２３ ％ 、－ ５１００ ％ 、１６２２ ％ 、２０８３ ％ 、４７３ ％ 和１１４３ ％ ， 其树高、胸径和木纹理扭转度的遗传增益分别为： １９５１ ％ 、１５３２ ％ 和１７４２ ％ 。滇中、滇东南和川西南母树林的种子不适宜在滇西种植。各性状间的关系较多地受基因连锁或共效基因的作用， 生长量性状和质量性状间存在着紧密的负相关， 树高具有较高的遗传力 ［ Ｈ２ （ ％ ） ＝６２９４ ％ ］ ； 说明用 “滇西云南松优良林分选择的方法和标准” 选择优良林分改建成的母树林， 所获得的良种具有极显著的增产效果。     

白马河林场云南松母树林种源初期试验研究

１９９２年在白马河林场用白马河林场、古永林场、保山林场的云南松母树林的种子与永仁县和全省商品种子营造子代林，作对比试验。１９９６年２月对子代林树高，地径，材积进行方差分析和差异显著性检验，并进行遗传力，遗传增益的估算。结果表明：母树林的子代林与商品种子的子代林在树高、地径和材积的生长量均存在着极显著的差异，材积生长量遗传增益为８３３％，地径生长量遗传增益为６７４％，树高生长量遗传增益为１６４７％。经对３个种源幼树期的生长分析，初步得出在白马河林场以古永林场的种源最好。不同地域的云南松母树林第一代初期的表现性状均较稳定。     

湖北省杉木种源试验

介绍了１９７７年和１９８０年在湖北省１３个试验点进行的杉木地理种源选择试验结果。通过９年生和６年生两次重复试验的结果表明，杉木种源的树高、胸径、材积、侧枝、冠幅、结实与抗寒性等性状存在显著的遗传差异，种源生长与环境互作明显，杉木种源生长幼龄阶段与速生阶段的秩次相关性强。采用多变量痤标综合评定法，为湖北省五大杉木造林区分别选出了相应的优良种源，其中锦屏、邻水、江华、那坡四个种源在湖北大多数地区表现优良，适应性较宽。优良种源材积的选择效益为３９．７％－１３４．５％。     

河南省杉木种源选择研究

对４９个杉木地理种源进行了生长发育及种源选择的研究。初步摸清了杉木在河南的变异规律。通过统计分析，用综合评定法评选出６个适宜河南生长的优良种源，优良种源的树高、材积分别比本省对照种源大１１．３％和３０％，增产效果明显。同时为河南杉木造林区提出调种的意见。     

云杉引种及种源试验研究

经长达１４～１５ａ的云杉引种和红皮云杉种源试验研究表明：青海云杉从西北引入齐齐哈尔北部克拜地区造林是成功的，生长良好，树高、胸径、材积分别比对照大４．１％、１５．０％和１９．８％；红皮云杉美溪种源在该地区生长量高，生长稳定，为最佳种源，树高、胸径、材积分别比对照大５．０％、１１．９％和２７．１％；云杉早期选择是可行的，５～６ａ可作为早期选择的初选年龄。     

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.