杉木福建柏混交林效益研究

通过对杉木福建柏混交林中单株生物量组成、土壤团粒组成、土壤孔隙和水分状况的研究分析， 结果表明： 混交林中杉木每ｈｍ ２ 蓄积量是杉木纯林的１６９ 倍， 细根量是杉木纯林的１５ 倍； 与纯林相比， 混交林中０～２０ｃｍ 土层＞ ０２５ｍ ｍ 水稳性团聚体高出９０１％ ； 结构体破坏率低１５８２％ ； 有机质和水解性 Ｎ 含量分别高０２４５％ 和１３１×１０－ ６； 毛管孔隙、非毛管孔隙、总孔隙高００９％ 、０９１％ 、１００％ ， 土壤容重低００５７ｇｃｍ － ３； 最大持水量、最小持水量、毛管持水量分别高３００％ 、３５０％ 、２０４％ ； 混交林４０ｃｍ 土层含水量也比纯林大１５５ｔ·ｈｍ － ２。由于混交林的结构较为合理，能一定程度改善土壤理化性质、提高林分生产力，是一种值得推广的造林模式。     

诱发桃形李煤污病的主导因子和防治方法

诱发桃形李煤污的主导因子是梨园蚧危害，该虫在浙江浦江１年３代，以受精雌成虫越冬。防治方法：２月中下旬，用３￣５度石硫合剂全面喷洒；４月中下旬，５０％杀螟松８００￣１０００倍液喷洒；６月中下旬，５０％甲基托布津０００倍液喷洒；１１月份，５０％久效膦６￣１０倍涂干。     

双体免充气日光温室的研制与应用

日光温室是在现代加温温室的基础上发展起来的节能型简易园艺栽培设施。由于高跨比小，后坡投影大，透光量不足，有效空间较小，难以满足花卉等高经济性作物大规模工厂化周年高效生产之需求。双体免充气日光温室是在综合多种优化模型分析的基础上提出来的。它在后墙上直接支撑双体免充气可拆式全透光整体曲面结构，其基本参数为跨度５ｍ，脊高２５ｍ，高跨比０５０，后墙高１８ｍ，后坡长１９ｍ，后坡仰角２２°，后坡投影为零，前坡１ｍ处的垂直高度１９ｍ，剖面截面积６４６ｍ２。对照试验表明：双体免充气型无明显的弱光胁地；在不覆草帘的冬季，早晨６时和中午１２时的最高温度分别比对照高２℃和６２℃；夏季５０％遮荫后，室内各点平均温度低于对照３℃；冬季保温效果则更为显著，大于８℃的有效积温分别是鞍山Ⅱ型和室外的１５倍和５３倍；秋、春两季切花月季栽培试验表明，鲜切花的产量和质量也明显高于对照，尤其是早春的盲枝发生率仅为对照的４０％。     

郝家流域针阔带状混交林效应观测

通过对郝家流域内３种混交林（油松×山毛桃、油松×沙棘、樟子松×沙棘）的综合因子进行调查，结果表明，混交林的枯枝落叶量分别是油松纯林的１５倍、３２倍、２７倍；林分总持水量分别是油松纯林的３３倍、８９倍、６４倍。由各树种１０年生长进程可以看出，樟子松×沙棘、油松×山毛桃的混交效果较好。     

龙眼扦插育苗及丰产栽培技术研究

采用文中所介绍的技术，龙眼扦插４０天后即产生愈伤组织，愈合率达８６６％；６０～９０天大量生根，生根率达８７２％，成活率达７４５％；９０天后即可进行苗地移栽，成活率达９０５％。１年生苗高６０～１５０ｃｍ，地径０６～１５ｃｍ，此时即可出圃定植。２～３年挂果，４年进入丰产期，丰产效果显著。     

巨尾桉无性系山地引种造林效果的研究

通过对引进巨尾桉无性系与巨桉、尾叶桉进行山地造林试验３年的研究结果表明,巨尾桉无性系不仅能适宜本地区山地栽培,而且生长快,３年生平均树高１２１ｍ,胸径１２３ｃｍ,单株带皮材积００７２８ｍ３,去皮材积００５７４ｍ３,比尾叶桉分别增长２３５％、２８１％、９２１％和１４０２％,比巨桉分别增长１３１％、１９４％、５６６％和５１５％。它还具有树干通直圆满、树皮较薄、冠径比小、出材率高、丰产性好等特点,可以大面积发展,并总结出栽培上的关键技术。     

自制生根剂三法

果树、花木繁殖方法有多种，用枝条扦插较为常见，用枝条扦插常使用生根激素（如萘乙酸等）处理，以提高成活率。这种药物较难买，不便急用。下面介绍三种可以自制的生根剂，供选用。１柳枝浸液　取筷子粗的柳枝数条（多少视需要量定），去其叶片，剪成３５厘米～７厘米长的若干小段，加适量清水浸泡１０天左右，树枝与水重量比大约为１∶１５～２，即１千克树枝用１５千克～２千克水浸泡，以滤液浸插穗５小时～６小时，然后扦插，处理后的插穗可提前７～１０天生根，成活率高，生长健壮。２糖水液　用蔗糖和沸水配成５％或１０％…     

3种粉剂防治鞭角华扁叶蜂幼虫药效试验研究

选用２．５％甲基对硫磷，９０％灭幼脲Ⅲ号原粉和３％敌死蜱，分别用陶土稀释５种浓度防治鞭角华扁叶蜂１－６龄幼虫，试验结果表明，７２ｈ死亡率，用２－８倍陶土稀释的２．５％甲基对硫磷达８７．６％～９７．９％，用２５－２５０倍陶土稀释的９０％灭幼脲Ⅲ号原粉达８５．６％－９７．１％，用２－８倍陶土稀释的３％敌死蜱粉剂达８５．４％－９９．２％，２．５％甲基对硫磷，９０％灭幼脲防治成本分别为２１．６５－２３．５     

神灯白掌组织培养快繁技术

以神灯白掌顶芽或茎段作为外植体,消毒后接种在培养基（１）：ＭＳ＋ＢＡ１０＋ＮＡＡ０１＋３％蔗糖,培养３０ｄ。将无菌材料转接在新配制的培养基（１）上,３０ｄ转接１次,如此反复继代,年繁殖系数达３６。生根培养采用培养基（２）：１／２ＭＳ＋ＩＢＡ０８＋１５％蔗糖＋００２％活性炭。瓶内平均发根率达９８％以上,温室内移栽平均成活率达９５％以上。     

苹果果形剂应用试验初报

对苹果进行苹果果型剂处理多点试验结果表明：苹果盛花未期喷施１５０—２００倍苹果果型剂，Ⅰ类果达３０％—４５５％，Ⅰ、Ⅱ类果达６２９％—８１５％；果形指数在０９５以上，最大值１２；处理果果个增大，呈园锥形，着色均匀，色泽浓红。应用果形剂是生产高档优质果品的重要技术措施之一。     

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.     

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。