半枫荷扦插繁殖技术试验

通过田间双因素试验设计研究了不同插穗基部下切口型（W）、不同扦插基质（P）对半枫荷扦插生根率、生根数的影响差异,通过田间正交试验设计研究了不同种类生根促进剂（C）、不同密度遮阳网（D）及不同木质化程度的插穗（E）对半枫荷扦插生根率、生根数及苗高的影响差异。试验结果表明：插穗基部下切口型采用双削面（W3）＋扦插基质采用各50%红心土和珍珠岩（P2）最好,平均生根率、生根数最高,平均生根率达到86.9%,平均生根数达11.9条;采用生根促进剂ABT-1#（C2）＋遮光率为50%的遮阳网（D1）＋半木质化的绿枝（E2）最佳,平均生根率达到89.6%,平均生根数达到12.6条,平均苗高达到22.8cm。     

沉水樟容器扦插快繁技术试验研究

通过双因素田间试验设计研究了不同长度插穗(M)和母株不同部位剪取的插穗(N)对沉水樟扦插快繁试验生根率、生根数的影响差异,还通过3因素3水平田间正交试验设计L9(34)研究了不同种类生根促进剂(P)、不同插穗基部下切口型(H)、不同木质化程度插穗(G),对沉水樟扦插育苗生根率、生根数和生根长的影响差异。试验结果表明:沉水樟扦插快繁试验中采用M3N2组合效果最好,即插穗长度为14cm(M3)结合母株中部剪取的插穗(N2)对沉水樟扦插快繁生根效果最好,平均生根率达84.9%、平均生根数达到10.6条。采用生根促进剂ABT-1#(P1)+插穗基部下切口型采用双削面(H2)+半木质化的绿枝(G2),即P1H2G2组合最佳,平均生根率达到86.6%,平均生根数达到12.6条,平均生根长达到15.7cm。     

不同处理对光皮桦容器扦插生根能力比较

通过田间试验设计研究了不同生根促进剂种类(A)及其浓度(B)对光皮桦扦插生根率及生根数的影响差异,不同木质化程度的插穗(C)及不同插穗长度(D)对光皮桦扦插生根率及生根数的影响差异,不同插穗下切口型(E)及母株不同部位的插穗(F)对光皮桦扦插生根率、生根数及生根长的影响差异。结果表明,采用ABT-1#(A1)800 mg.kg-1(B3)效果最好,扦插苗生根率高且生根数多;选择半木质化的绿枝插穗(C2)及插穗长度采用10.0～12.0 cm(D3)效果最好,扦插苗生根率高且生根数多;插穗下切口型采用斜切(E3)及配合母株中部(F2)所产的插穗对光皮桦扦插生根率、生根数及生根长均有显著差异。     

西南桦冬季落叶插穗容器扦插育苗技术研究

通过试验设计研究西南桦母株不同部位剪取的插穗(A)、不同基部径粗的插穗(B)及不同长度的插穗(C)对西南桦冬季落叶插穗容器扦插生根率、生根数及生根长的影响差异,比较了不同插穗下切口型(D)、不同轻型基质网袋容器(E)对西南桦冬季落叶插穗扦插生根率的影响差异。结果表明:西南桦母株中部剪取的插穗(A2)+基部径粗在2.1mm~3.0mm的插穗(B2)+长度16cm的插穗(C3)组合最好,其生根率高、生根数多且生根长;不同插穗下切口型的扦插试验中,以双削面(D3)最好;不同轻型基质网袋容器的扦插试验中,以E8最佳。     

厚皮香容器扦插育苗技术试验

通过双因素试验设计对4种不同生根促进剂种类（H）、6种不同生根促进剂浓度（S）对厚皮香容器扦插生根率的不同影响力进行了研究,同时还研究了5种不同扦插基质（G）及3种不同母株部位剪切的穗条（X）对厚皮香容器扦插生根率的影响差异。结果表明：不同的生根促进剂种类和不同生根促进剂浓度对厚皮香扦插生根率的促进作用是显著的,生根促进剂种类对扦插生根率的影响力大于生根促进剂浓度,以采用质量分数为750×10-6（S5）的IBA（H3）处理,厚皮香插穗生根率高,达85.4%;基质及母株采穗部位对厚皮香扦插生根率的影响显著,母株采穗位对厚皮香扦插生根率的影响力大于基质,以母株下部（X3）剪切的插穗扦插到各50%的红壤和珍珠岩（G2）基质时,生根效果最好,平均生根率达87.9%。     

福建山樱花容器扦插育苗技术试验研究

通过田间试验设计探索3种不同类型生根促进剂(W)、4种不同生根促进剂浓度(P)对福建山樱花容器扦插生根率、生根数的影响差异。通过正交试验设计研究了不同插穗基部下切口型(G)、不同长度插穗(D)以及不同木质化程度插穗(M)对福建山樱花容器扦插生根率、生根数及生根长的影响差异。结果表明:在福建山樱花3种不同类型生根促进剂、4种不同生根促进剂浓度容器扦插试验中,使用质量分数为650×10-6(P3)ABT-1#(W1)来处理插穗生根效果最好,平均生根率达到86.5%,平均生根数达到11.8条;插穗基部下切口型采用双削面(G3)+16cm长插穗(D3)+半木质化的绿枝(M2)组合最好,其平均生根率高、生根数多且根长生长最大。     

白果蒲桃扦插快繁技术研究

采用4种不同种类生根促进剂(G)及3种不同生根促进剂浓度(S)双因素试验设计,研究了不同处理下的白果蒲桃扦插生根率、生根数的差异,采用正交试验设计L_9(3~4)研究了不同长度插穗(D)、插穗基部不同下切口型(E)及不同扦插基质(A)对白果蒲桃扦插生根率、生根数及生根长的影响差异。结果表明:使用质量分数为850×10-6(S_3)的生根促进剂ABT-1~#(G_4)处理白果蒲桃插穗时扦插效果最好,平均生根率达76.3%,平均生根数达8.3条;采用长度为13cm的插穗(D_2)+两边各与插穗成45°双楔面下切口(E_3)+各50%红壤和蛭石粉作为扦插基质(A_1)时,白果蒲桃扦插效果最佳,平均生根率达80.9%,平均生根数达9.7条,平均生根长达12.3cm。     

紫玉兰容器扦插快繁技术研究

通过双因素试验设计研究了生根促进剂种类(Q)、生根促进剂浓度(G)对紫玉兰扦插生根率、生根数的影响差异;还通过正交试验设计L8(27)研究了插穗木质化程度(D)、插穗长度(U)、插穗基部下切口型(Z)及扦插基质(S)对紫色玉兰扦插生根率、生根数的影响差异。试验结果表明:使用浓度为500×10-6(G2)生根促进剂IBA(Q2)来处理插穗时对紫玉兰扦插效果最好,平均生根率达80.7%、平均生根数达10.5条;采用未木质化的嫩枝(D1)+插穗长度为15cm(U2)+插穗基部下切口型为双削面(Z2)+扦插基质为各50%红壤和珍珠岩(S1)、即采用D1U2Z2S1组合时对紫玉兰扦插效果最显著,平均生根率达86.1%、平均生根数达12.8条。     

三角梅扦插繁殖技术研究

通过试验研究了4种不同生根促进剂（ABT-1#）浓度及3种不同木质化程度的插穗对三角梅生根率、生根数及生根长的影响。结果表明：生根促进剂（ABT—1#）质量分数6．0×10^-4＋半木质化的绿枝试验效果最好,生根率高达96．8％、生根数达8．6条、生根长达10．3cm。     

白玉兰容器扦插快繁技术试验

采用L8(2^7)正交试验设计研究2种不同生根促进剂(U)、2种不同生根促进剂浓度(G)、2种不同木质化插穗(N)及2种不同长度的插穗(M)对白玉兰插穗生根率的影响,用双因子方法比较了3种不同配比的扦插基质(S)及3种不同插穗基部下切口型(W)对白玉兰扦插生根率的影响。结果表明:采用浓度750mg kg^-1(G2)ABT-1^#(U1)生根促进剂来处理长度为12cm(M1)的白玉兰硬枝(N1)插穗时生根率最高,平均生根率达83.7%;3种不同插穗基部下切口型和3种不同配方的基质扦插试验中,以插穗双边各成45°斜切(W3)扦插到各50%红壤和珍珠岩(S3)中时生根效果最佳,平均生根率达85.3%,平均生根数达15.6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.