不同杨树无性系品种引种栽培试验

对4年生的杨树无性系引种试验表明：（1）JP14和JP15两无性系的各项测试指标超过其它无性系，生长最优；（2）JP13、JP14、JP15三无性系树冠较窄、分枝角小、枝细、生长较快，可作为农田防护林的主栽树种。     

油茶湘林系列6个无性系嫁接苗生长调查

对湘林系列5、14、15、18、40、166等6个油茶优良无性系的芽苗砧嫁接苗生长情况进行了调查。调查结果为：6个无性系平均成活率和抽梢率的变化范围分别为74．6％-96．2％和71．3％-93．6％，平均苗高和地径的变化范围分别为13．5-19．8cm和0．303-0．356cm，平均叶片数和冠幅值变化范围分别为8．7-12．7片／株和7．3-8．6cm，平均根长和根幅变化范围分别为6．0-6．8cm和4．7-6．5cm。6个无性系平均成活率和抽梢率分别为85．O％和88．5％，分别大于对照5．0％和2．1％；平均苗高和地径分别为15．8cm和0．33cm，分别大于对照1．4cm和0．022cm；平均叶片数为10片／株，大于对照0．8片／株；平均冠幅、根长和根幅分别为8．0cm、6．5cm和5．4cm，分别大于对照0．43cm、0．25cm和0．78cm。湘林166和湘林5的芽苗砧嫁接苗生长表现较好，其平均成活率、抽梢率及苗高、地径、叶片数量、冠幅与根长等均较大；湘林15和湘林40则生长表现较差，其平均成活率、苗高、叶片数量等均略低于混合优良无性系（对照）苗。     

杨树优良无性系介绍

浙江省林业科学研究院经过10年的引种试验,优选出3个适合浙江省发展的优良杨树新无性系—T-20杨、T1杨和102/74杨。 T20杨和T1杨系是从南京林业大学王明庥院士选育的15个南方型杨树无性系中优选出的优良无性系,1994年引入浙江省桐庐县试种;1024/74杨原产意大利,从山东省引进试种。经引种试验,3个无性系具有成活率高、生长快、抗性强等特点,当年生扦插苗高达到4 ~ 5m,胸径2cm,造林成活率普遍达到99%以上,4m?m的8年生杨树林分平均胸径达到30cm、树高16m以上,超过对照I-69杨30%以上,比35/66杨高10%以上。 3个无性系均表现出很强的抗性,在试验…     

美洲黑杨S307-26和PE-19-66区域化造林试验初报

通过引进全国各地选育出的34个杨树新优良无性系，在山东省各杨树栽培区进行了苗期试验和区域化造林对比试验。结果表明：S307—26和PE-29-66生长表现较好，两个无性系的4a生平均胸径、平均树高和平均单株材积经方差分析均与对照Ⅰ-69／55达极显著差异，4a生平均单株材积分别超过对照Ⅰ-69／55杨31．0％和40．8％，造林和育苗成活率也都与对照Ⅰ-69／55相当或强，同时还具有抗病虫害性能强、材质好和生态适应范围广等特点；通过对S307—26和PE-19-66进行形质指标测定和形态描述，认为这两个无性系为美洲黑杨南方型品种。经综合测试和评价后初步认为，S307—26和PE-19-66可在山东省各杨树栽培区推广应用。     

美洲黑杨引种苗期试验初报

为了丰富当地杨树种质资源,从南京林业大学引种4个美洲黑杨无性系进行扦插育苗试验,结果表明：4个无性系中,895杨、797杨、95杨在当地均有良好的生长适宜性,其苗高分别为对照加拿大杨的124．3％、116．8％和114．2％,地径分别为对照加拿大杨的159．3％、136．5％和133．9％。关键词：美洲黑杨;引种;苗期试验;成活率;生长量     

海滨湿地杨树、柳树新无性系苗期耐盐性研究

在海滨湿地分别4个盐度梯度，12种杨树、柳树新无性系田间扦插试验结果表明：在苗期，不同杨树、柳树无性系的成活率、保存率、生长量等均与土壤含盐量呈负相关；在出苗期的耐盐能力，1-74杨、1-69杨可达0．241％，35杨为0．188％，J30-16、J35-13、J4-34、J31-17柳为0．089％，其余5个柳树无性系均在0．060％以下；在苗木生长期，其耐盐极限分别为0．343％，0．333％和0．201％。     

35杨等杨树无性系育苗不同密度对比试验

选择目前江苏连云港地区比较适宜生长的35、95、107、土耳其杨树等4个优良杨树无性系,在东海县牛山综合试验场,进行了3种密度育苗试验,结果表明:采用40 cm×50 cm、40 cm×60 cm的育苗密度,不论是1年生还是2年生苗木的质量均比育苗密度30 cm×50 cm的苗木质量明显提高,其经济效益也明显增加,是连云港地区的杨树育苗最佳密度。     

杉木优良无性系区域化试验初报

采用广东、湖南和贵州3个省40个杉木优良无性系，于1998年在广东大坑山林场进行区域化试验。结果表明：6年生单株材积生长55％的无性系优于对照，其中达较显著差异水平以上的有4个无性系，广东3个，湖南1个。广东提供的无性系表现较好，其中生长表现较优的GDL041、GDL043、GDL044三个无性系单株材积达较显著差异水平以上，占参试无性系的33％，其次为GDL042、GDL046无性系，其单株材积增益均达25．1％以上，在本省亦经过了3次以上重复试验，表现均较优，可大面积在广东造林推广应用。     

欧美杨胶合板材新品种试验

1995年，在河南省焦作市对18个杨树优良无性系进行了品系比较试验。结果表明：供试杨树优良无性系存在着显著的遗传差异；各无性系在树高、胸径指标上差异极显著或显著；杨树优良无性系G2杨胸径生长较对照有较大的速生优势；910--95和6--15杨在河南省焦作地区不仅生长快，而且干形好、抗虫。     

10个速生杨品系对比试验研究

以山海关杨为对照,在唐山地区进行不同杨树无性系对比试验。经过7a试验,结果表明：108杨生长表现突出,107杨次之,白杨表现最差。7a生108杨林木平均胸径、平均树高和平均单株材积分别为20．3cm、15．57m和0．1500m^3,超过山海关杨1．18倍、1．30倍和4．15倍;多重比较表明,108杨和107杨各生长指标与对照差异达极显著,同时该无性系还具有造林成活率高、抗性强等优良特性,可以在唐山地区推广应用。     

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。     

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.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.