日本落叶松整形修剪对母株生长、产穗量、插穗生根和扦插苗生长的影响

研究了高，中柱式，矮台式整形修剪方法对不同年龄（2-10a生）日本落叶松采穗母株生长，产穗量，插穗生根（无激素处理）及2a生扦插苗生长的影响。结果表明：日本落叶松实生幼年母株每年进行整形修剪，虽然不能完全抑制老龄化对母株插穗生根的影响。但有助于幼化复壮母株组织。未加整形修剪的10a（实际为9.5a)生树形母株的插穗生根率只有24.8%。而同龄经不同剪控措施处理的母株插穗生根率可达55.2%-81.1%(平均64.9%)，均极显著地大于对照。整形修剪方式不同，对母株生长（地径），产穗量和插穗生根率等的影响不同。高，中柱式母株由于修剪相对较轻，生长量大，产穗量高，3.5a,5.5a和8.5a生3个年龄阶段平均产穗量分别为110.5,237.0,173.0穗和85.9,150.7,98.0穗，均显著或极显著地大于矮台式母株（相应地分别为54.3,61.4,43.0穗）。高，中柱式母株虽在生长和产穗量方面具有明显的优势，但母株5.5a生以后插穗生根率呈下降趋势，至9.5a生时骤降至58.3%,55.3%。受连年重剪的影响。矮台式母株生长量小，产穗量小，死亡率高，但延缓老龄化和幼化效果好，7.5a以后插穗生根率才开始下降，与高，中柱式相比，母株插穗生根率开始下降的年龄推迟约2a，并且生根率下降的幅度小，至9.5a生时仍可达81.1%。母株幼年阶段（2.5a生）整形方式对2a生扦插苗的生长影响不明显，但当母株达到一定年龄阶段后（7.5a生）矮台式母株2a生扦插苗高度（44.8cm)显著大于高柱式母株（33.4cm)。为充分发挥采穗母株生产潜力和剪控的幼化效果，日本落叶松幼年实生母株在建圃最初几年应采用高柱式修剪，一定年龄阶段后（8a生）采用再截干幼化处理的方法降低母株高度，以改善插穗生根效果和延长采穗圃使用年限。     

长白落叶松嫩枝扦插技术研究

利用全光雾插技术对长白落叶松半木质化插穗扦插育苗研究表明：夏插３０ｄ后开始生根，从扦插至大部分插穗生根（７２．７％）需要７２ｄ时间。２．５ａ生插穗未经激素处理生根率达７０．８％，利用２００ｇ／ＬＩＢＡ溶液浸泡２０ｍｉｎ后，插穗生根率提高到８０％；不同采穗母株间插穗生根率变异幅度为３２％～９５．３％，差异达到极显著水平；不同年龄插穗经２００ｇ／ＬＩＢＡ溶液处理后生根率随母株年龄的增大而降低。     

母株年龄和插穗基部切削方式对日本落叶松生根的影响*

在无激素处理的条件下，１．５年生幼龄母株的插穗易于生根，平均生根率达９６．０％以上，且发根最大，偏根率低；４．５年生时，插穗生根率极显著低于１．５年生母株，而与８．５年生母株无显著差异；１２．５年生母株插穗生根率又极显著低于８．５年生母株。母株年龄与插穗生根率和偏根率分别呈显著的负相关（ｒ＝－０．９６５２）和极显著正相关（ｒ＝０．９９９３），但与生根量和平均最长根长度无显著相关。插穗基部切削方式不     

柳桉组培苗嫩枝扦插繁殖技术

为降低生产成本,加快繁殖速度,选取柳桉组培苗采穗母株上的半木质化枝条为试材,开展了嫩枝扦插试验。结果表明：生长激素IBA的浓度、扦插基质和组培苗插穗母株的年龄是影响柳桉嫩枝扦插育苗生根的重要因素,但IBA的处理时间以及IBA浓度与处理时间的交互作用对生根无显著影响;从1—2年生的组培苗采穗母株上选取穗条,以黄心土：糠壳灰（V：V=3：1）为扦插基质,插穗用IBA100mg／L浸泡处理0．5h是柳桉嫩枝扦插的最佳处理组合,其生根率达90％以上,平均每株生根数达5条以上。     

费约果母株繁殖方式和插穗成熟度对扦插生根的影响

采用二因素随机区组试验设计,研究了费约果母株繁殖方式和插穗成熟度对嫩枝扦插生根的影响。结果表明：母株繁殖方式和插穗成熟度对嫩枝扦插生根状况的影响达到显著水平,2年生实生苗半木质化插穗生根性状明显优于其他处理,其生根率为78．95％,插穗的平均生根数量为6．67条,平均根长为15．80cm。     

采穗园母株生根性状遗传变异和选择效应*

对３．５年生日本落叶松采穗园４个家系４０株母株生根率、生根量和偏根率遗传变异，不同生根性状间表型相关研究表明，家系间生根率、生根量和偏根率差异尚达不到０．０５的显著水平。但不同母株间上述差异均极显著。单株生根率、生根量等的遗传力大于家系，方差分量分别比家系大４～３６倍。部分家系生根率与生根量、偏根率之间相关关系紧密程度不同，但生根量与偏根率之间各家系均呈极显著负相关。根据生根率、生根量综合评价结果，按５０％入选率对采穗园进行淘汰，或用生根性状优异的母株扦插苗建第二轮采穗园，插穗生根率、生根量比总体利用水平可分别提高２０．３％和２９．８％，而又不致严重减少采穗园母株的遗传多样性。     

日本落叶松硬枝扦插育苗研究初报

采用幼龄母株上已处萌发生长状态的１年生木质化硬枝作插穗，在全光照喷雾条件下扦插，生根率达９０．１％，当年换床移栽苗成活率达９２．３％，２年生移植苗平均高４４．１ｃｍ，地径０．６４ｃｍ．     

桉树插插育苗的十大关键环节

现将桉树扦插育苗的十大关键环节简介于下。 1．采穗母株。用组培苗作母株，插穗生根状况好。 2．母株年龄。母株年龄在1-3a生时，采穗扦插生根率高。     

插穗生根进程和粗细不同对落叶松扦插苗的影响

调查研究了日本落叶松１年生木质化枝春插生根进程和插穗直径粗细不同对扦插苗生根、生长的影响。在辽东气候条件下，萌发态木质化枝插后４９天开始生根，至２４天时生根率可达８６％以上。插穗直径≤２．５ｍｍ，生根率低。插穗直径增大，扦插苗生长和生根性状可得到明显改善，直径３．６～５．０ｍｍ的插穗生根率高达９４％以上。选用直径粗细适宜的插穗可大幅度提高日本落叶松硬枝扦插育苗效果，降低成本。     

插穗生根进程和粗细不同对落叶松扦插苗的影响

调查研究了日本落叶松１年生木质化枝春插生根进程和插穗直径粗细不同对扦插苗生根、生长的影响。在辽东气候条件下，萌发态木质化枝插后４９天开始生根，至２４天时生根率可达８６％以上。插穗直径≤２．５ｍｍ，生根率低。插穗直径增大，扦插苗生长和生根性状可得到明显改善，直径３．６￣５．０山的插穗生根率高达９４％以上。选用直径粗细适宜的插穗可大幅度提高日本落叶松硬枝扦插育苗效果，降低成本。     

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。     

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.     

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.     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.