丹桂短穗扦插育苗技术

开展不同母树年龄、不同扦插时间、不同生根促进剂种类及浓度、不同基质等因素对丹桂当年生半木质化枝条扦插生根率的影响试验。试验结果表明:丹桂母树树龄越小,扦插成活率越高,1-2年生母树扦插成活率达88%;丹桂扦插应避开7-8月份高温天气,其余时间均可扦插育苗;以河沙+黄心土(1:1)为扦插基质,插穗经GGR6#50mg.L-1浸泡处理,扦插成活率可达91.5%。     

提高马尾松扦插繁殖成活率研究

采用沙床和容器2种方法进行马尾松扦插繁育试验,选取珍珠岩、河沙及河沙+黄心土+草木灰混合进行不同基质扦插对比,在母树下部、中部及上部采集穗条扦插比较,生根剂不同浓度及处理方法进行扦插,研究表明:①以河沙、黄心土、草木灰混合或珍珠岩为基质进行容器扦插培育马尾松无性苗,其成活率和成苗率高,扦插苗生长快,起苗容易,苗木根系损伤小,造林成活率得到保证;②马尾松穗条扦插存在位置效应,母树中上部穗条与下部穗条扦插成活率差异显著,中上部穗条扦插成活率达90%以上;③用低浓度生根剂处理插条后蘸取含有相应浓度生根剂泥浆扦插,能大幅度提高马尾松穗条扦插成活率。     

蓝浆果扦插育苗技术比较研究

运用正交试验对ABT生根剂处理蓝桨果插条的处理浓度、处理时间、枝条类型和扦插基质4个因素进行了比较,结果表明,生根剂不同浓度,不同枝条类型和不同扦插基质对蓝浆果扦插育苗成活率有显著影响,在南昌地区9月中旬开展蓝浆果扦插育苗,选取当年生春梢做插条,采用ABT生根剂100mg/kg或50mg/kg处理插条4h或8h,并扦插在黄心土上,能有效提高成活率。     

北美红杉扦插育苗试验初报

为获取北美红杉大量的扦插苗木,通过不同扦插条来源、不同育苗基质、不同生长激素及不同生长激素浓度处理插条4因素3水平的正交试验,研究不同处理其对扦插苗生根率、根长、根数的影响.试验结果表明影响北美红杉插条生根的主要因素是扦插条,选用母树年龄小的枝条或采用树根基部1年生半木质化萌生条,用作扦插条的生根性能较好.以树根基部1年生半木质化萌生条用插条、蛭石作育苗基质、用200mg/L的ABT1号生根粉浸泡插条6h处理组合为最佳组合.     

印楝扦插繁殖技术研究

2002~2005年,开展了印楝扦插繁殖试验,对影响生根成活率的基质、插穗材料、生根剂、扦插季节、扦插后管理等因子进行了研究。结果表明,较佳的扦插技术组合为:塑料杯育苗以无菌黄心土∶河沙(3∶1)作为基质,苗床育苗以等量的黄心土和河沙混合为基质,扦插前一天用10 g/L高锰酸钾液消毒,在春季和夏季采集当年生刚木质化或半木质化枝条和萌芽条作为插穗,用1 g/L吲哚丁酸生根粉处理插条后扦插,插后育苗床注意保温保湿,生根率可达80%以上。     

云南红豆杉扦插育苗中的插条与基质选择试验

2006年12月在云南省林业科学院昆明树木园的苗圃内选用了4种类型的插条和4种基质进行了云南红豆杉扦插育苗的效果试验.经2007～2008年连续两年对不同插条类型、育苗基质的扦插成活率及其扦插苗高径生长观测与分析,表明:在云南红豆杉扦插苗培育中,选取萌生枝条尤其是带有顶芽的萌生枝条作为插条,并用混合土(即1/3生土+1/3蛭石+1/3腐殖土)做基质,是一种较为合理的搭配.     

云南红豆杉扦插繁殖成活率与枝条处理关系的研究

阐述云南红豆杉扦插育苗技术的要点,如基质选择、插床整理、扦插时间、插条母树选择、枝条处理等环节。对扦插苗苗床和生根后的管理以及换床培养技术作了介绍。经过2001~2005年连续5年实验对比后得出结论:用蜂蜜和ABT生根粉作为红豆杉扦插处理剂成活率最高。     

北美红杉扦插育苗试验初报

为获取北美红杉大量的扦插苗木，通过不同扦插条来源，不同育苗基质，不同生长激素及不同生长激素浓度处理插条4因素3水平的正交试验，研究不同处理其对扦插苗生根率，根长，根数的影响，试验结果表明，影响北美红杉插条生根的主要因素是扦插条，选用母树年龄小的枝条或采用树根基部1年生半木质化萌生条，用作扦插条的生根性能较好，以树根基部1年生半木质化萌生条用插条，蛭石作育苗基质，用200mg/L的ABT1号生根粉浸泡插条6h处理组合为最佳组合。     

桂花扦插繁殖技术研究

在粤北对桂花进行扦插繁殖试验,对不同扦插基质、促根素、扦插时间及插条母树年龄的扦插效果进行对比,结果表明:扦插基质以黄心土效果最佳,生根率达90.9%;促根素以NAA+IBA混合处理效果最佳,成活率达91.0%;扦插时间宜在1~2月进行,插条宜选择3~10年生母树2年生健壮枝条。     

桂花扦插繁殖技术研究

在粤北对桂花进行扦插繁殖试验,对不同扦插基质、促根素、扦插时间及插条母树年龄的扦插效果进行对比,结果表明：扦插基质以黄心土效果最佳,生根率达90．9％;促根素以NAA＋IBA混合处理效果最佳,成活率达91．0％;扦插时间宜在1～2月进行,插条宜选择3～10年生母树2年生健壮枝条。     

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.