专用纸浆材遗传育种现状及思考

当今,纸浆材树种由过去的针叶树种为主体转向针、阔树种协调发展;良种选育由过去只注重提高纤维产量向产量与制浆品质并重方向发展;育种技术向杂交育种和基因工程方向发展。作者在综述国内外纸浆材遗传育种现状和我国发展纸浆材基地政策基础上,提出了短周期优质纸浆材育种策略、育种程序、技术路线、研究内容和育种指标。     

桤木优良造纸材改良潜力研究

对桤木优树树高、胸径、材积、单株纤维量、纤维长、纤维长宽比、纤维含量、木材密度的变异规律和各性状间的相关关系进行了研究。结果表明:性状变异系数规律是生长性状大于材性性状;各性状间没有显著相关,各性状可独立改良;材积、纤维含量、木材密度对单株纤维量的贡献率分别为67.47%、17.02%、15.51%;各性状的改良潜力是:材积可达1倍以上,胸径48%,树高18%,木材密度可提高10%以上,纤维含量可提高4%以上,纤维长度、长宽比分别可提高7%、12%以上,生长与材性联合改良的效益在30%以上。     

桤木纸浆材幼林施肥试验初报

以四川桤木纸浆材新造林作为研究对象进行肥效试验,结果表明:施基肥对幼林的树高生长有明显的促进作用;对一年生幼林每株施0.5 kg桤木专用复混肥与不施肥之间的差异显著,而每株施0.25 kg与每株施0.5 kg之间差异不显著。     

Determinants of farmers' adoption and adaptation of alley farming technology in Nigeria

Understanding the factors affecting framers' adoption of improvedtechnologies is critical to success of implementing agroforestry developmentprograms. This paper evaluated the determinants of farmers' decisions to adoptand adapt alley farming technology and its variants in the farming systems ofNigeria, using econometric Logit models. Eleven variables were significant inexplaining farmers' adoption decisions. The model results show that farmercharacteristics that influenced adoption included the gender of the farmer,contact with extension agents, years of experience with agroforestry and tenancystatus in the village. Economic factors, proxied by village-levelcharacteristics that condition resource use incentives, were also significant.These variables include the extent of village land pressure, extent of erosionintensity, village fuel wood pressure, importance of livestock as an economicactivity in the village and the distance of the village locations from urbancenters. The paper showed that farmers are already making significantmodifications to the conventional alley farming technology introduced byscientists. The two most important modifications were the introduction of fallowperiods into the conventional system and changes in the pruning regime of thesystem. Model results showed that human capital variables were significant inexplaining farmers' decisions to adapt and modify the technology. Farmereducation and family size significantly influence the choice of pruning regime.Farmers' age, education, intensity of erosion in the farmers' village, andfarmers' land availability significantly influence whether or not fallowperiod is introduced into the conventional system. To promote greater adoptionof agroforestry alternatives to slash-and-burn agriculture, particular attentionshould be placed on the use of appropriate socioeconomic characterization, tobetter target technologies to areas with higher adoption potential. This revised version was published online in June 2006 with corrections to the Cover Date.     

An analysis of Greek wood and wood product imports: Evidence from the linear quadratic aids

The consumption of wood and wood products in Greece is based greatly on imports necessitating every year a great proportion of public expenditures. The study of wood and wood product imports consequently, is important to the national economy and can be a useful guide for the forest farms, wood industries and wood firms. In this paper the Greek aggregate import demand for Unprocessed wood (such as logs) Processed wood (such as sawn wood), Veneer Crafts (such as veneer sheets) and Wood Manufactures during the period 1969–2001 is empirically analysed using the linear approximation of quadratic AIDS (QUAIDS) model. Imports of Unprocessed wood, Veneer Crafts and Wood Manufactures are found to be price-elastic, in contrast to Processed wood imports. Processed wood, Veneer Crafts and Wood Manufacture imports are found to be expenditure-elastic while Unprocessed wood is found to be an inferior good. Substitution possibilities are found to be significant between Veneer Crafts and all the remaining wood imports and between Processed wood and Unprocessed wood.     

Excess demand,monopsonistic price setting and stochastic input supply

This paper tries to reconcile casual empiricism of what has been happening in the pulpwood market in Sweden with a stochastic version of the theory of monopsony. This means that the firm, which is using wood as an input in production, has to make a price and/or quantity decision before the actual supply curve of pulpwood is revealed. We show that excess demand tendencies are to be expected, if the production function is close to linear in the wood input. We also show that pricing behavior and stochastic supply can explain why the paper and pulp industry often produces at a lower level than full capacity utilization.     

The consequences for the forest sector of nuclear power discontinuation in Sweden

Electricity prices in Sweden will most probably double, or more, during the next 10 to 15 years as a result of the decision to discontinue nuclear power production. This will substantially change the comparative advantage of all forest‐based product industries, some to the worse, some to the better. Roundwood prices and fellings will be affected and possibly the competitive position of wood‐based energy production. This paper estimates various types of effects with a long run pulpwood market model. The effects on electricity intensive production (CTMP, newsprint, etc.) may be drastic. However, the fall in total industrial consumption and price of pulpwood will be limited. The reduction in price is not sufficient to make pulpwood economically attractive as fuel. Own‐price elasticities of electricity demand are greater than reported elsewhere.     

Taxation and investment implications of non-industrial private forestry within a Boreal Swedish municipality

The Swedish tax system affects distribution of forest revenue between national, municipal and individual interests. The study reported here takes a Boreal municipality perspective, with the objective of investigating the tax and investment implications of non-industrial private forestry (NIPF) in a case-study municipality at these three interest levels. Sales revenue, operating costs, investment, disposable income and direct tax revenue generated in NIPF within the boreal municipality are quantified, drawing on income tax return data. The question addressed is, does NIPF contribute to the local economy and thereby to development and maintenance of infrastructure in a typical boreal municipality, given the present NIPF ownership structure and tax system? Results support two different views. On one hand, tax revenues generated from NIPF to the resource municipality amounted to only 17% of the direct tax revenues or less then 1% of the tax revenues in the municipality budget. On the other hand, NIPF owners returned as much as 72% of sales revenue back into their firms in form of operating costs, and 20% in from of investments.     

我国纸浆材需求现状

随着中国人均生活水平的提高,对纸和纸制品的消费量也日渐增多起来。由于人为的不断破坏和乱砍滥伐使得全球森林资源逐年在下降,作为制浆造纸工业的主要原料的木材也在逐年减少,解决纸浆材供应与利用问题,是当今世界林业及造纸工业发展的重要研究课题。文章从对我国森林资源进行分析,简要说明现今我国对纸浆材的需求现状,并举例说明了林纸一体化的对策。     

Use of wood products in multi-storey residential buildings: views of Swedish actors and suggested measures for an increased use

ABSTRACT

Many studies have shown that wooden buildings in general have a lower climate impact than buildings built of conventional materials such as concrete and steel. In Sweden, however, only about 10% of the multi-dwelling buildings are built with timber frames. The goal of this empirical study is to provide a broad picture of the views of Swedish actors regarding the use of wood products in multi-storey residential buildings and suggest measures for an increased use. A questionnaire concerning the use of wood products in construction was sent out to Swedish developers, main contractors, and architects and 100 answers were received. The study shows that the views of the groups of actors differ in some respects and factors that may either facilitate or be obstacles to an increased use of wood products were identified and discussed.     

云南松胶合板材、纸浆材种源选择

“云南松胶合板材、纸浆材种源选择”是多性状综合评选，把生长与多用途选育结合。本材料取自1981年营造的种原试验林和部分天然林内，共选取13个产地，38件试材，作木材解剖，物理性能和化学成分含量等测定．经分析各种源间木材的各理化性状的差异达权显著水平．并获得与胶合板、纸浆材关系较密切的是种源间年均材积生长量（X1）、树干纹理通直度（X2）、木材密度（X3）、管胞长（X4）、纸浆得率（X5）．根据性状遗传力（H2）及它们的经济重要性估算权重值（W），建立“两材”的种源综合选择指数方程：①I板＝214．0571X1＋0．29859X2＋0．37736X3和②I纸＝214．0571X1＋0．06212X4＋0．39278X5。按①和②综合选择式，评选出乐业、红河、双柏、双江、石屏、开远、富宁等8～10个适于“两材”高产优质种源，材积平均遗传增益达47．3％，树干纹理通直率达87％～98％；单位面积上木材干物质重提高18．0％～49．6％，纸浆得率18．4％～49．7％。胶合板的抗压、抗弯强度等力学指标均有提高，胶合强度1．97～2．58MPa＞0．8MPa（GB指标），手抄纸的耐破度，裂断长，撕裂度均达到观指标。使“两材”的种源选择建立在遗传型的基础上．同时为各生态区提出供选择的丰产种源。     

四川桤木纸浆材耐干旱优良家系选择初探

四川桤木造林成活率的差异达到了极显著或显著水平,造林当年的家系间成活率变幅为50%~100%,平均为78.1%;存活株第2年的成活率变幅为52%~100%,平均为73.7%。2年生家系树高生长量方差分析,家系间差异有3个层次达到极显著。以树高生长量大于试验平均值(1.60 m),同时成活率大于试验平均值(73.7%)进行选择,有光皮桦、19、6、4、24、10、18号家系入选,最优家系19号树高生长达到1.73 m,第2年的成活率达到100%。在较干旱区域造林,要选择耐干旱的四川桤木优良家系或光皮桦。     

四种算法用于近红外测定制浆材材性的对比研究

采集了常见制浆材(桉木、相思木及杨木)样品的近红外光谱,测定了样品的基本密度、综纤维素、木质素和苯醇抽出物含量,用人为控制水分的方法测定了样品的水分含量。对原始光谱进行预处理后,分别运用偏最小二乘法(PLS)、LASSO算法、支持向量机法(SVR)和人工神经网络法(BP-ANN)建立基本密度、水分含量、综纤维素、木质素和苯醇抽出物含量的预测模型。对预测模型进行独立验证,结果显示:LASSO算法建立的基本密度和综纤维素模型性能最优,其预测均方根误差(RMSEP)分别为0.006 3 g/cm~3和0.49%,绝对偏差(AD)范围分别为-0.008 8~0.009 6 g/cm~3和-0.85%~0.87%;PLS建立的水分含量模型及苯醇抽出物模型最优,RMSEP值分别为1.21%和0.24%,AD范围分别为-1.99%~2.03%和-0.35%~0.38%;SVR建立的木质素模型最优,RMSEP值为0.43%,AD范围为-0.76%~0.74%,均满足制浆造纸工业中对误差的要求。     

甘肃干旱荒漠区纸浆林三倍体毛白杨营建试验

本文分析了2001年作为纸浆林发展引种的10个三倍体毛白杨系号在石羊河流域造林的生长适应性。结果表明:在同一立地类型和同等抚育条件下,A129、A128、B330、A125、B1008、BT85、A122等7个无性系杂种三倍体毛白杨幼林在石羊河流域速生、抗寒、耐盐碱、抗黄斑星天牛,在石羊河流域表现出较强的适应性和抗逆性,生长量显著高于普通毛白杨、群众杨、新疆杨;由于其速生性使黄斑星天牛不能完成生活史而不至于造成危害;在专用纸浆林方面大力推广具有良好的发展前景。     

马尾松纸浆材育种研究进展及策略

介绍世界各国的松树材性改良的概况及研究进展,材性研究包括木材基本密度遗传变异、木材纤维形态遗传变异、木材化学组成遗传变异和木材材性性状之间相关性,并提出了马尾松纸浆材遗传改良的策略。     

Cost minimization through the use of taungya system in pulpwood plantation establishment

The costs and benefits of the use of three labour alternatives: direct permanent, direct casual and taungya labour in Gmelina arborea pulpwood plantation establishment in Nigeria were investigated. Results show that cost per hectare is lowest with taungya labour and highest with permanent labour with savings in cost of as much as 30% and 47% by taungya labour over casual and permanent labour respectively. The net present value per hectare of investment is highest when taungya labour is used and lowest and negative with permanent labour. Also, the internal rate of return of investment is highest with taungya labour and lowest with permanent labour. The net present values and internal rates of return for Gmelina plantations calculated for the three pulp and paper mills in Nigeria show the same trend in favour of taungya labour.     

Response of Coniferous Forest Ecosystems on Mineral Soils to Nutrient Additions: A Review of Swedish Experiences

Nitrogen (N) is the only nutrient that promotes forest growth when given individually. An extra stem growth of 15 m 3 ha -1 is obtained during a 10 yr period following an application of 150 kg N ha -1 . Larger growth increases have often been the result of more intensive N fertilization. Lime or wood ash give a minor growth stimulation on sites with a carbon (C) to N ratio below 30 in the humus layer, while the opposite effect prevails on N-poor sites. Nutrients given as soluble fertilizers are readily taken up by trees. Boron deficiency may be induced in northern Sweden after N fertilization or liming. The ground vegetation may be altered by single-shot N fertilization, but long-term effects occur only for intensive regimes. Lime or wood ash may modify the flora if soil pH is significantly altered: the change will be in response to N availability. Fruit-body production of mycorrhizal fungi is disfavoured by chronic N input, but also by lime or ash. However, the mycorrhizal structures on root tips are less affected. Faunistic studies are not common and those present are mostly devoted to soil fauna. A practical N dose of 150 kg N ha -1 has no clear effect, but higher doses may reduce the abundance in some groups. Hardened wood ash does not significantly affect the soil fauna. Lime favours snails and earthworms, while other groups are often disfavoured. The response of aquatic fauna to terrestrial treatments has hardly been studied. N fertilization generally results in insignificant effects on fish and benthic fauna. Lime and wood ash reduce the acidity of the topsoil, but practical doses (2-3 t ha -1 ) are too low to raise the alkalinity of runoff unless outflow areas are treated. N fertilizer use in forestry and N-free fertilizers lack effects on acidification. N fertilization may, however, be strongly acidifying if nitrification is induced and followed by nitrate leaching. N fertilization often results in increased long-term C retention in trees and soil, but does not promote significant N 2 O losses. N may temporarily reduce CH 4 oxidation in soil, but there are indications of a long-term opposite effect. Lime and poorly hardened wood ash may cause losses of C from N-rich soils. Only a few per cent of added N are leached to surface water following practical N fertilization, while N-free fertilizers do not induce N leaching. Soil incubations and soil-water studies suggest an increased risk for nitrate formation and leaching where lime or wood have been added to N-rich soils, but increased leaching to surface water has not been observed. Wood ash causes a temporal increase in bioavailability of cadmium (Cd). Other fertilizers may indirectly increase the availability of heavy metals. Wood ash may contain radioactive caesium 137Cs, but addition of such ash does not increase radioactivity in plants and soil.     

马尾松纸浆材密生型家系的选择

通过"基因型×密度"的互作试验,证实了基因型与密度存在着明显的互作效应,且不同家系与密度的互作方式不一.评选出纸浆材密生型家系33个,其遗传增益达21.21%～161.21%,以此奠定了马尾松造纸材密生型家系选择的理论依据.     

Forest discourses and the role of planning-related perspectives: the case of Sweden

Forest use in Sweden may be seen as constituting an essentially conflicted area, in which a number of actors position themselves. Based on a review of policy documents, this study reviews discourses on forest amongst major organisational actors between 2001 and 2011, with the aim of discussing the ways in which discourse may have changed following increasing criticism of the previously dominating production paradigm during the period. The study also discusses the ways in which forest discourses at present may also exclude areas that are relevant to forest planning. Results illustrates the continuous role of, on the one hand, production and private ownership discourses among the forest industry, and, on the other, conservation and public access discourses, among environmental and other NGOs. Large differences thus continue to exist despite the double aim towards production and protection in Swedish forest law. Areas that are not directly related to this nexus although related to land use at large, such as municipal planning, on the other hand, are largely absent from discourse even if, for instance, shore planning and wind power issues that are related to municipal planning are taken up.     

Effects of seedbed substrate on moisture conditions and germination of Scots pine (Pinus sylvestris) seeds in a mixed conifer stand

The objective of this investigation was to comparemoisture conditions and Scots pine (Pinussylvestris L.) seed germination percentages in fourtypes of seedbed substrates, (i.e., feather mosses,mineral soil, humus, and ground organic material). Twoexperiments were conducted, with and withoutirrigation, in the summer of 1996 in a stand innorthern Sweden. The moisture conditions weredetermined by periodically weighing seedsamples. When plots were not irrigated, no seedsgerminated, probably because conditions were too dryin the seedbeds, as indicated by the low seed moisturecontent (under 15%). However, during rainy days, seedmoisture contents were relatively high (20–45%). Onthe irrigated plots the seeds germinated on allseedbed substrates, with the best germinationoccurring in humus (about 40%). Seed moisturecontents were high and relatively consistent in allirrigated seedbed substrates (35–55%). Inirrigated plots temperature rather than moisture, wasa limiting factor, and germination was highest in thewarmest seedbed types which are generally regarded aspoor germination substrates. We suggest that seedbedsin areas scheduled for harvesting be prepared in thestand before clear-cutting, and that the preparationshould enhance not only the substrates's water-holdingcapacity, but its thermal conductivity as well.