油茶高产栽培系列技术研究———配方施肥试验

以油茶优良无性系成林和幼林为材料,通过随机区组和正交试验,结果表明配方施肥对油茶优良无性系成林和幼林产果量增加均有不同程度的促进作用.油茶成林对产果量最大的影响因子是施肥总量,其次是微量元素肥、施肥频率和施肥配比;较合理的施肥配比组合应为:施肥总量(200 kg·hm-2) 微量元素肥(Zn 10 g·株-1) 施肥频率(连续3年施肥) 施肥配比(5∶1∶5),增产幅度可达58.69%.油茶成林鲜果出籽率最大影响因子是微量元素肥、其次是施肥总量,施肥配比和施肥频率;而每500 g鲜果数最大影响因子是施肥配比、其次是微量元素肥、施肥频率和施肥总量等因子;油茶优良无性系新造幼林施肥也能明显提高油茶单株产果量,其中以间年施肥、每年施肥量为N∶P2O5∶K2O为2∶1∶2;平均单株产果量达1.16 kg,比对照增产136.4%.增施磷肥能明显促进油茶幼林早期挂果.配方施肥对油茶幼林鲜果出籽率没有明显的影响.     

油茶F1代试验林树高、冠幅、产果量的相关性分析

为给良好树形结构的设定及产量预测提供参考,根据2003～2005年闽侯桐口林场的油茶杂交F1代试验林连续3a的生长量调查数据,对49个处理的树高、冠幅、单株产果量的平均数据进行相关性分析和主成分分析。结果表明冠幅与单株产果量间存在显著相关性。对两者进行一元非线性回归模型分析得到回归曲线和回归方程,进一步了解两者间的相关性,同时作出产果量的预测。     

岑软3号油茶无性系树高、冠幅与产果量关系的研究

采用显著性分析、偏相关分析及回归分析研究岑软3号油茶无性系树高、冠幅与产果量的关系。结果表明:树高和冠幅显著影响产果量,其中冠幅对单株产果量影响较大;冠幅与树高呈极显著正相关关系;单株产果量随着冠幅及树高的增大而增加,树高达2.5 m后不同树高植株间产果量差异不显著;得出通过树高、冠幅预测单株产果量的回归方程,表明在保证合理树高的条件下,积极培育冠幅可显著提高油茶产果量。     

湖南省油茶林产量调查研究

通过连续7年对湖南省25个油茶林样地的产量状况进行调查测定,结果表明:油茶自然低产林平均产果量只有2 382 kg/hm~2,油茶低产林经改造后产量提高2.01倍,4年平均产果量达到了4 788 kg/hm~2。油茶林采用良种+良法,造林第四年产果量1 249.5 kg/hm~2,第五年产果量3 075 kg/hm~2,第六年产果量5 497.5kg/hm~2,盛产期产果量9 757.5 kg/hm~2。油茶花期,油茶花芽分化与油脂转换高峰期的气候条件对油茶产量有较大的影响,尤其是油茶盛产期良种林,由于其产量高,对水、养分等需求量大,更容易受花期低温阴雨、高温干旱等灾害性气候的影响。     

油茶花、果及春梢生长相关性研究

为了掌握油茶"大小年"现象的成因,为油茶的花果平衡调控技术提供依据。研究了5年生、9年生2种不同林龄油茶花、果及春梢生长的相关性,结果表明:(1)花芽数与当年春梢数呈正相关,其中5年生林呈极显著正相关(p0.01);与当年的植株产果量、座果率呈负相关,其中5年生林分别呈显著(p0.05)、极显著(p0.01)负相关。(2)5年生油茶林中只有5%的植株为单株挂果量、花芽数量、座果率较为均衡;30%的植株为单株挂果量较大,当年花芽分化受到明显的抑制;25%的植株为单株挂果量与花芽数量均较少;40%植株为单株挂果量较小,当年花芽数量较多。(3)9年生油茶林中15%植株单株产果量与花芽数均较高,单株挂果为3.98~5.92 kg,花芽数为1 360~1 500个,座果率为18.9%~44.1%;25%的植株单株挂果量较大,花芽数量明显减少;30%植株单株产果量与花芽数均较低,35%的单株产果量较低,花芽数较多。     

试论油茶的花期选择

我国油茶选优比较有系统的开展始于1963年,叶培忠教授等在江西宜春油茶林场,进行了单株选优,指出“当前油茶选育工作迫切任务主要是通过优良单株的选择来建立良种基地”,并提出了优株选择包括产量的四个标准。此后,各地陆续开展了这项工作,七十年代初研究发现单株产量与冠幅投影面积有很强的相关性,相关系数r=0.95,从而把绝对产果量改为冠幅投影单位面积产量为标准,发展至现行以树冠投影平方米产油量为决选标准。虽然除产量指     

橄榄优良品系G18适应性试验

在高州市三个试点开展橄榄G18品系适应性试验,结果如下：利用8～9年生橄榄树改接后第4年及1年生砧木嫁接后第9年,其平均单株产果量达22．9kg,单株平均增产15．1kg,产量增益216．82％;平均单位树冠投影面积产果量达0．77kg／m^2,平均增产200．01％;试点间单株产果量和单位树冠投影面积产果量的变异系数（CV）分别接近或小于试点内的CV;改接株平均冠幅生长量与对照接近,但1年生砧木嫁接株的比对照大18．75％。G18嫁接亲和性较好,生长较快,丰产性好,立地适应性强,是一个值得在生产上大力推广的优良品系。     

延平区油茶优良单株选择

对福建省南平市延平区油茶重点种植区初选出的175株单株进行排序,筛选出29株作为参选单株;运用F检验、相关系数分析、主成分分析以及聚类分析等数理统计方法,对参选单株的树高、地径、冠幅面积、单株产果量、冠幅产量、鲜出籽率、干出籽率、种仁含油率等8个指标进行综合评价,最后评选出28号、29号为该地区的优良母株。     

橄榄优良品系“粤榄18”适应性试验

在高州市三个试点开展橄榄“粤榄18”品系适应性试验,结果如下：利用8～9年生橄榄改接第4年及1年生砧木嫁接后第9年, 其平均单株产果量达22.9kg,单株平均增产15.1kg,产量增益216.82%;平均单位树冠投影面积产果量达0.77kg/m2,平均增产200.01%;试点间单株产果量和单位树冠投影面积产果量的变异系数（CV）分别接近或小于试点内的CV;平均冠幅生长量改接株接近不改接的植株,但1年生砧木嫁接株的比对照大18.75%。“粤榄18”嫁接亲和性较好,生长较快,丰产性好,立地适应性强,是一个值得在生产上大力推广的优良品系。     

油茶优良品系的初步介绍

<正> 从八十年代初开始,在麻城市林业局、五脑山林场配合下,我们在五脑山林场开展了油茶良种选择工作。通过10多年来对12. 6亩1011株油茶高产示范林的观察和单株产量测定,从中选择出五年平均单株产果量在13kg 以上的高产植株60株,并进行连续三年的含油率测定,然后又从这60株高产植株中,选择出单株产果在15kg 以上,种仁含油率在45%以上高产量,高含油率植株10株,进行无性系测定试验。目前,已经取得了结果早、丰产性好的初步效果,能较快地提高油茶产量,可以在生产中推广应用。现将这10个高产优良株系介绍如下,供各地发展油茶时参考。     

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.     

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.     

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.     

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。     

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.