他迎来中国中国木浆的曙光——记朱之悌教授选育纸浆材新品种

北京林业大学教授朱之悌经过10多年的艰辛努力,改造我国特有树种毛白杨一些根本特性,实现了国家攻关课题“毛白杨短周期纸浆材新品种选育”提出的要求,填补了中国白杨造纸无专门造纸品种的空白,完成了我国工程化营建速生优质造纸用材林     

毛白杨胶合板用材林适宜采伐年龄的研究

以山东毛白杨胶合板用材林主要品种鲁毛系列毛白杨为研究材料,通过对用材林树干解析和生长指标分析,利用现代生物统计技术,分析其数量成熟龄、工艺成熟龄和经济成熟龄,讨论以旋切单板用原木的山东毛白杨胶合板用材林的适宜采伐年龄.结果表明:500～666株/hm2(株行距4m×5m～3m×5m)是培育胶合板用材林的适宜密度,适宜采...     

三倍体毛白杨引种栽培试验初报

三倍体毛白杨是当今世界上最速生、优质用材白杨派杨树短周期纸浆材杂交新品种 ,由我国著名林木遗传育种专家、北京林业大学朱之悌教授潜心研究 15年 ,应用高科技实验手段——细胞工程及相应配套技术培育成功。该成果居国内外领先水平 ,填补了我国三倍体用材树种空白。“三倍体毛白杨的育成是国之骄傲”,它解决了我国北方地区工业用材林发展长期缺乏优良树种的难题。为了积极稳妥地推广三倍体毛白杨 ,从 2 0 0 0年开始 ,新和县对引进的 6个三倍体毛白杨品系进行育苗试验 ,与乡土树种新疆杨相比 ,三倍体毛白杨具有育苗周期短 ,当年育苗当年出…     

毛白杨和用材林立地类型划分和质量评价

作者分别在鲁西黄泛冲积平原区和鲁中南、胶东山麓河谷平原区对毛白杨用材林进行典型调查，并在综合分析调查研究结果的基础上，进行了毛白杨用材林立地类型划分和质量评价。鲁西黄泛冲积平原区划分了１４个立地类型，鲁中南、胶东山麓河谷平原区划分了１８个立地类型，各立地类型的立地指数在１１￣１９之间。其中立地指数１６以上的立地类型，立地质量较好，可作为毛白杨用材林的适生立地条件类型。     

毛白杨用材林立地类型划分和质量评价

作者分别在鲁西黄泛冲积平原区和鲁中南、胶东山麓河谷平原区对毛白杨用材林进行典型调查，并在综合分析调查研究结果的基础上，进行了毛白杨用材林立地类型划分和质量评价。鲁西黄泛冲积平原区划分了１４个立地类型，鲁中南、胶东山麓河谷平原区划分了１８个立地类型，各立地类型的立地指数在１１～１９之间。其中立地指数１６以上的立地类型，立地质量较好，可作为毛白杨用材林的适生立地条件类型     

塞罕坝人工用材林大径材培育之分析

塞罕坝人工用材林大径材培育是通过适当降低林分的保留密度,加速人工用材林生长,培育大径材,取得一定的经营技术和成功经验,促进本场及全省用材林大径材培育的发展,为森林健康、可持续经营提供科学依据.     

马尾松大径材林分密度的探讨

分析马尾松大径级用材林林分密度与生长量、材种出材量和直径分布的关系,结果表明,为获得较多的大径材,培育马尾松大径材用材林以初植密度1 200～1 800株/hm2和最终保留密度750～1 050 株/hm2为宜.探讨了马尾松大径级用材林培育技术措施,提出抓紧编制大径级用材林基地建设规划,并制定大径级用材林培育技术标准等建议.     

用嫁接法繁殖毛白杨

用嫁接法繁殖毛白杨娄庆元毛白杨是我国北方地区特有的速生用材树种，分布广泛，栽培历史悠久，具有生长快，寿命长，树干高大通直、材质好等特点。是四旁绿化、农田林网和营造用材林的重要树种。由于毛白杨扦插育苗很难成活，只能依靠根蘖少量繁殖，所以毛白杨很难成林。...     

东平湖区平原毛白杨立地指数表的编制

东平湖区平原毛白杨立地指数表的编制张树江井庆山（东平县林业局东平湖周围为湖区平原地，毛白杨是该地用材林、速生丰产林和农田林网的主栽树种之一。该区西至黄河，东至大清河，立地变化较大。为选择毛白杨适生立地，为造林营林提供技术依据，我们在该区选择毛白杨林分...     

毛白杨苗木不同强度截梢造林效果分析

毛白杨苗木不同强度截梢造林效果分析姜岳忠（山东省林科所，济南２５００１４）毛白杨是营造速生丰产用材林的主要树种之一。但是幼林时期往往出现顶梢生长不明显、枝杈横生、树干弯曲等现象，不仅延长成材年限，而且降低木材质量。为此，我们进行了毛白杨苗木不同强度截...     

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.