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.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.     

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。     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.