杉木优良家系区域试验研究

１９８４年春对靖州县排牙山林杨杉木种子园选出的１１个优良家系分别在怀化地区北部、中部和南部进行了区域性造林试验。历时１０年，结果表明：优良家系间与环境间交互作用显著，但都优于对照。材积增产率比种子园混系种大２３．６％，比一般生产用种大４２．６％，平均遗传增益２２．６％。     

湿地松不同家系造林增产效率研究

在子代测定的基础上筛选出优良单亲家系进行中试造林，探讨了各家系相互间在有无竞争的条件下其生长量的差异。在家系间相互存在竞争的情况下，１０年生国产湿地松单亲家系比对照（进口商品种子）材积生长增产２４．５％，最优家系０－１０２７材积增产达７０．３％；在没有竞争的条件下，６年生家系试验林比对照林分增产７５．３８％，其中最优家系０－１０２７比对照林分增产１２０％，家系示范林比对照林分增产８３．０８％。     

湿地松不同家系造林增产效益研究

在子代测定的基础上筛选出优良单亲家系进行中试造林，探讨了各家系相互间在有无竞争的条件下其生长量的差异。在家系间相互存在竞争的情况下，１０年生国产湿地松单亲家系比对照（进口商品种子）材积生长增产２４．５％，最优家系０－１０２７材积增产达７０．３％；在没有竞争的条件下，６年生家系试验林比对照林分增产７５．３８％，其中最优家系０－１０２７比对照林分增产１２０％，家系示范林比对照林分增产８３．０８％。     

杉木优树—家系—无性系的层次选择

通过子代造林测定，从３５个杉木家系中选择出２５个优良家系，其９年生材积增益可达４５．９２％，再从入选的１０个家系中选择９９株优良单株繁殖成无性系，经造林２年后，从中选出７个优良无性系，其树高增益可提高３７．１２％。建议从初建采萌圃中淘汰平均表现以下的无性系，并在当地推广入选的优良无性系，以提高良种应用水平。     

杉木优良家系无性群体造林效果

杉木家系无性化造林与原家系实生苗造林的生长趋势基本一致，保持着原有家系的基因型特性。１８个杉木家系（组合）３年生时，平均树高比对照大２０．８４％，胸径超过３２．９％，其中有１５个家系树高、胸径的增幅均在１０％以上，较优良的５个家系和３个杂交组合，树高大于对照２０．２０－４５．７％，胸径大于对照３１．７７－６５．５％，表现出较高的生产潜力，可在闽北及类似地区进行无性繁殖，大面积推广。     

西南桦优良家系苗期选择的研究

通过对西南桦（Betula alnoides Buch-Ham）78个家系（含对照）苗期生长的调查，分析了苗高、地径、冠幅、主根长、根幅和≥5cm侧根数等6个性状间的相关性及在家系间的差异，采用主分量分析法（PCA）对各家系进行二维排序，从而进行苗期选择营建种子园，以降低表型选择的误选率，提高种子园的质量，在77个家系中筛选出优良家系66个，占家系数的85.71％，其中Ⅰ级优良家系20个，占家系数的25．97％；Ⅱ级优良家系46个，占家系数的59．74％；淘汰11个家系，占家系数的14.29％。优良家系的生长量与选择前相比有了较大幅度的提高，各性状的标准差也相应有所降低。     

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     

杉木第二代种子园子代测定效果分析

本文对福建省官庄林场杉木第二代种子园自由授粉子代试验林树高、胸径和材积等生长性状进行了研究。子代测定结果表明，参试家系间的效应显著；利用方差分析的结果，估算了杉木树高、胸径和材积的家系遗传力和单株遗传力，并以１０％、２０％的选择强度估算出杉木的遗传增益值。通过分析得出杉木各生长性状间有较高的相关性。依材积选择出４６个优良家系，用作造林，４年生时估计其遗传增益可达４１．３７％～５１．３７％。     

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２     

宁波市杉木优良家系区域性试验

１９５９年，将初选出的３５个优良家系作进一步的区域性试验，经过４ａ观测研究后认为．①６１号等８个家系，表现突出，在我市推广，增产明显，②选出的１７株优树，同初级良种相比，第４年增产１３８．２％，成熟期可望增产３７．７％，③杉木４ａ生时，进行选择是较为可靠的．     

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.