板栗种子室外密集土藏试验小结

板栗属淀粉类坚果,在贮藏过程中,既不耐干、又不耐湿,既怕冻害、又怕鼠害。过去板栗室内贮藏往往稍有疏忽,就会造成大量霉烂变质或干枯。为解决板栗种子大批量贮藏管理难的问题,作者于1986年秋末进行了板栗种子室外密集土藏试验,现将试验效果小结如下:1.材料与方法1.1.材料.供试板栗系采摘后及时脱棚的坚果,其中沅陵小果油栗5395kg,麻阳毛板栗350kg。     

板栗种子蜡封贮藏方法

板栗种子在贮藏过程中易霉烂 ,易失水。经试用蜡封贮藏 ,收到理想效果。具体做法是 :1　适时采收适时采收是影响板栗种子安全贮藏的关键。做种子用的板栗要让其充分发育成熟 ,果肉充实饱满 ,水分含量较低 ,可显著提高其自身耐贮藏的能力。2　种子蜡封前的处理板栗种子在蜡封贮藏前 ,要进行必要的筛选分级和防虫防腐处理。在密闭的室内用溴烷熏蒸 4ｈ～ 8ｈ ,可有效防止虫害 ,每平方米用溴烷 40ｇ～ 5 0ｇ ;用 5‰ 2 ,4-Ｄ与托布津5 0 0倍液浸种 3ｍｉｎ可防腐。浸种时粘在种皮上的药液要充分晾干。3　蜡封将购来的石蜡用大铁锅熬化 ,液体石…     

板栗简易高效贮藏方法试验与分析

通过对影响板栗贮藏因素的分析和试验结果的观察,比较了层积沙藏和混合沙藏方法的优劣,为板栗以及其他林木种子的安全贮藏提供了参考资料。     

栗链蚧的发生规律与防治

栗链蚧 (ＡｓｔｅｒｏｌｅｃａｎｉｕｍｃａｓｔａｎｅａｅＲｕｓｓｅｌｌ)是东海县板栗生产上的一种主要虫害 ,发生面积大、程度重 ,严重威胁板栗的发展。 1997～ 2 0 0 1年 ,我们在东海县的山左口乡、房山镇两地 ,对该虫害的发生规律和防治方法进行了研究 ,摸清了栗链蚧在当地的发生规律 ,总结出了一套行之有效的防治技术。1　危　害栗链蚧的雌成虫和若虫主要危害板栗的枝干。枝干受害后表皮下陷 ,凹凸不平 ;当年生新梢受害后 ,表皮皱缩、干裂 ,秋后干枯而死。越冬成虫的形状、颜色、大小均和栗树枝条表皮的皮孔相似 ,在低虫口时极易混淆 …     

林业应用稀土的技术与效果

稀土在提高林木种子发芽率，促进杉木（Ｃｕｎｎｉｎｇｈａｍｉａ ｌａｎｃｅｏｌａｔａ（Ｌａｍｂ．）Ｈｏｏｋ．）、木荷（Ｓｃｈｉｍａ ｓｕｎｅｒｂａ Ｇａｒｄｎ，ｅｔ Ｃｈａｍｐ）、板栗（Ｃａｓｔａｎｅａ ｍｏｌｌｉｓｓｉｍａ Ｂｌｕｍｅ）、泡桐（Ｐａｕｌｏｗｎｉａ ｓｐ）、杨树（Ｐｏｐｕｌｕｓ ｓｐ）等的苗期生长提高苗木质量，提高湿地松（Ｐｉｎｕｓ ｅｌｌｉｏｔｔｉｉ Ｅｎｇｅｌｍ）、杉木种子园的种     

板栗贮藏保鲜问题及解决措施

为给板栗的贮藏保鲜提供理论依据和技术指导,概述了板栗贮藏保鲜过程中的常见问题及解决办法：贮藏保鲜期间板栗质量下降的主要表现（栗实的腐烂变质、风干失重,栗实的发芽）;影响板栗贮藏保鲜的因素及机理（贮藏期间栗实的生理变化,不同产区不同品种板栗的耐贮性,不同的采收和堆制方法,贮藏保鲜场所的环境条件）;贮藏保鲜期间防止板栗损耗的主要措施（贮藏前的科学准备和防止栗实发芽）;板栗贮藏保鲜的几种方法（简易贮藏、低温冷藏、辐射贮藏、气调贮藏和空气离子贮藏）。     

板栗疫病的侵染循环规律

板栗疫病的侵染循环规律王新花潘若良王会永张兴忠王玉杰（泰安市泰山林场２７１０００）李东军李洪敬（山东省林木保护站）板栗疫病（病原为Ｃｒｙｐｔｏｎｅｃｔｒｉａｐａｒａｓｉｌｉｃａ,Ｅｎｄｏｔｈｉａｐａｒａｓｉｔｉｃａ）危害板栗的枝干,常造成整株、整枝死...     

四法冬贮林木种

冬季要贮藏好林木种子,关键是控制种子的呼吸强度。为此,应综合运用以下四法,保证林木种子贮藏质量。晒种去杂大部分林木种子在贮藏以前都要晒干或阴干。凡种皮坚硬,安全含水量较低,在一般条件下不会迅速降低发芽力的种子,均可利用日光曝晒使种子干燥。大部分针叶树(圆柏除外)、豆科、翅果类及含水量低的蒴果种子等均可用此法。但有些林木种子,如栎类、板栗等,一旦干燥便很快脱水,迅速丧失生命力,因而不适宜晒种。一些种子小、种皮薄、成熟后代谢作用旺盛的种子,如杨、柳、榆、桑等,或含挥发性油脂的种子如花椒等,要摊放在通风良好的室(棚)…     

板栗简易贮藏保鲜技术

总结了板栗五种贮藏方法和贮前种子的药剂处理对其贮藏保鲜率的影响,指出:湿砂和湿木屑层积堆藏的贮藏保鲜率高,同时具有催芽作用,可作为种用栗的贮藏方法;罐藏和冷藏贮藏保鲜率也较高。可作为食用栗的贮藏方法;板栗贮藏前,一定要经过药物处理。     

天然油菜素内酯对油松和刺槐种子发芽的影响

油菜素内酯是一种新型植物甾体激素 ,近年来 ,在农业上得到了广泛的应用 (郭奇珍 ,1 983;李凯荣等 ,1 998;骆炳山 ,1 986;赵毓橘等 ,1 986;朱广镰 ,1 992 ;Ｉｋｅｋａｗａｅｔａｌ.,1 991 ;Ｍａｎｄａｖａ ,1 988;Ｙａｍａｇｕｃｈｉｅｔａｌ.,1 987)。但在林业上的研究报道甚少 ,特别是油菜素内酯对林木种子萌发及下胚轴伸长的影响未见报道。本文以水土保持林主要树种———油松 (Ｐｉｎｕｓｔａｂｕｌａｅｆｏｒｍｉｓ)、刺槐 (Ｒｏｂｉｎｉａｐｓｅｕｄｏａｃａｃｉａ)种子为材料 ,研究了天然油菜素内酯对其萌发及下胚轴伸长的影响 ,以便…     

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.     

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。     

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 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.     

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.