杉木选优挖蔸移栽促萌试验研究

本研究在全国首次提出并通过５年多的试验研究表明：于杉木中、幼林中选优砍伐,挖蔸移栽建圃,是一项行之有效的促萌新技术,移栽成活率达９０％～１００％,当年平均单株产条量３０～４０枝,与传统的就地砍优促萌方法相比,具有建圃快、产条量高、便于管理、节省采条用工等明显优点;比较系统的解决了移蔸优树适宜年龄、最佳移蔸时间、营养枝留养、移植母株根系发育规律等一系列关键技术问题,特别在营养枝留养及其与根系发育和萌条产量之间关系方面有新的发现,使本项技术更加系统化和实用化,为杉木原种圃、采穗圃的管理提供科学依据。     

柳窿桉芽器官离体培养研究

用10年生柳窿桉优株伐倒后的萌条为外植体，建立“以芽繁芽”的组培快繁体系。丛生芽培养基为MS BA1mg/L NAA0．2mg/L，繁殖率可达5．3倍；继代培养采用MS BA1mg/L NAA0.2mg/L和MS BA0.5mg/L NAA0.5mg/L交替使用，可促进芽的增殖和芽生长；经过壮芽培养可提高生根率，壮芽培养基为无激素服培养基；生根培养基为1/2MS IBA0．5mg/L，生根率达100％。     

思茅松促萌及扦插试验

在宁洱县对高产脂思茅松进行采穗母株促萌及不同采穗母株年龄、不同扦插时间对穗条生根率的影响试验,结果表明,不同采穗母株最佳促萌效果是修剪时在母株上留枝长度2 cm;根外施尿精30 g/株,采穗母株穗条产量最高;随着采穗母株年龄增加,穗条生根率下降,1年生母株穗条扦插成活率最高,可达73.04％,4年生母株穗条扦插成活率仅24.13％;每年最适宜的扦插时间为10、11、12月,穗条生根率高达71.5％以上.     

思茅松促萌及扦插试验

在宁洱县对高产脂思茅松进行采穗母株促萌及不同采穗母株年龄、不同扦插时间对穗条生根率的影响试验,结果表明,不同采穗母株最佳促萌效果是修剪时在母株上留枝长度2 cm;根外施尿精30 g/株,采穗母株穗条产量最高;随着采穗母株年龄增加,穗条生根率下降,1年生母株穗条扦插成活率最高,可达73.04%,4年生母株穗条扦插成活率仅24.13%;每年最适宜的扦插时间为10、11、12月,穗条生根率高达71.5%以上。     

楸树根、枝萌条扦插育苗技术的研究

■树的根、枝萌条经500—700 ppm NAA溶液速蘸处理后扦插,生根率可达77.8一86.1%。其中根段萌芽时间比枝条长,但根萌条扦插生根时间比枝萌条短。基质以土沙(1∶1)混合生根率高。萌条扦插苗根系数最多,移植成活率在95%以上。该方法简便,成本低,苗木生长好,是培育楸树自根苗的新途径。     

丛生竹插枝造林建立笋材两用林的研究

丛生竹笋材两用林的竹种,大多数中央主枝和主枝基部芽萌发的次生枝均极粗壮,犹如缩小了的母竹,枝蔸如竹蔸,具有笋芽和根点,可以当作母竹作繁殖材料。本项研究,采用吊丝球竹[Dendrocalamus beecheamus(Munro)Chiaet Fung]的主枝和次生枝直接营造笋材两用林,面积达200公顷,每公顷种植900坎,每次插2枝。成活率达90—95％,当年新竹平均高2.42米,最高达3.62米;平均地径2.1厘米,最大3.7厘米,第2年平均高6.01米,最高达8.20米,平均胸径6.9厘米,最大8.33厘米,每公顷平均收获竹笋1995公斤,最高达3675公斤。第3年高逾10米。胸径8—10厘米,平均每公顷产笋和竹材各1.2万公斤左右,进人正常年产量。插枝造林竹种来源广,成本低,成活率高。生产竹笋和竹材的能力,与用母竹造林无区别。该项研究成果已在广西、广东、云南等省区大面积推广。     

绿竹的立竹密度结构试验

应用随机区组试验方法在立地条件及经营措施基本相同的情况下对绿竹 (绿高脚品种 ) 4种密度结构测定其产量 ,其结果是以 30 0 0株·hm-2 的产量显著高于其它密度结构的产量 ,说明绿高脚密度结构应以 5 0 0丛·hm-2 ,每丛保持 6株 (年留笋养竹 3株 )最为适宜     

巨桉组培快繁技术研究

通过对巨桉离体芽器官的诱导培养和繁殖 ,探讨巨桉茎段诱导、丛生芽分化、生根的适宜培养基和适宜培养条件。结果表明 :适宜巨桉茎段诱导培养基为B1(或MS) 6 BA 0 1～ 1 0mg/L NAA 0 1～ 0 2mg/L ,适宜分化丛生芽的理想培养基为改良B1 6 BA 0 1～ 0 2mg/L NAA 0 1～ 0 2mg/L ,生根培养基为 1/2MS IBA 0 1mg/L ABT1 0mg/L或B2 IBA 0 1mg/L ABT 1 0mg/L ,生根率达 95 %以上 ,移栽成活率可达 93%以上。     

几种观赏竹种组织培养研究

以金镶玉竹等 11种观赏竹为试验材料 ,采用新萌发的嫩芽 ,在 MS BA 1.0 mg/ L (单位下同 ) IBA0 .1;MS BA1.0 KT0 .1 IBA0 .0 1;MS KT1.0 TDZ0 .0 0 1;MS BA5 .0 KT0 .1 IBA0 .0 1;MS BA1.0 KT0 .5培养基上成功获得 7种观赏竹的再生植株 ,丛生芽每2 0～ 4 0天继代 1次 ,不定芽增殖达 3～ 6倍。无菌苗移载成活率达 90 %以上。     

笋用竹良种选育的研究初报

为了培育优良的笋用竹,以提高竹笋的营养价值,改善其风味,进行了笋用竹良种选育研究.其方法是:引进优良的品种,并与本地的竹种杂交,从中选择其优良的无性系,结果表明:(1)麻竹与版纳甜龙竹、清甜竹杂交,已获得成功,其笋味不苦;(2)撑篙竹×麻竹7号,其竹笋的营养成分以及氨基酸总量和人体必须氨基酸的含量均高于其他种的竹笋,且产量高,加工性能好;(3)实生苗在试管内培养植株间生长差异大,其芽丛经生根诱导,生根率达60%;(4)人工促进萌发的次生枝扦插繁殖成活率达60%.并详细介绍了营建采萌圃的具体步骤.     

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.