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1.
对湘林系列5、14、15、18、40、166等6个油茶优良无性系的芽苗砧嫁接苗生长情况进行了调查。调查结果为：6个无性系平均成活率和抽梢率的变化范围分别为74．6％-96．2％和71．3％-93．6％，平均苗高和地径的变化范围分别为13．5-19．8cm和0．303-0．356cm，平均叶片数和冠幅值变化范围分别为8．7-12．7片／株和7．3-8．6cm，平均根长和根幅变化范围分别为6．0-6．8cm和4．7-6．5cm。6个无性系平均成活率和抽梢率分别为85．O％和88．5％，分别大于对照5．0％和2．1％；平均苗高和地径分别为15．8cm和0．33cm，分别大于对照1．4cm和0．022cm；平均叶片数为10片／株，大于对照0．8片／株；平均冠幅、根长和根幅分别为8．0cm、6．5cm和5．4cm，分别大于对照0．43cm、0．25cm和0．78cm。湘林166和湘林5的芽苗砧嫁接苗生长表现较好，其平均成活率、抽梢率及苗高、地径、叶片数量、冠幅与根长等均较大；湘林15和湘林40则生长表现较差，其平均成活率、苗高、叶片数量等均略低于混合优良无性系（对照）苗。 相似文献
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沙棘育苗通过地膜覆盖处理后，沙棘的成活率为79．1％，平均株高为17．8cm ，平均地径为0．24cm ，出苗率为82．4％。 相似文献
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牡蛎蚧壳虫是危害花椒树生长的毁灭性害虫之一。其若虫和雌成虫刺吸花椒树枝条汁液，导致树势衰弱，甚至使树枝干枯或全株死亡。近年来，韩城市盘龙、西庄、王峰等乡镇的盛果期花椒树屡遭危害，使大量老椒树整株枯死、据笔者在西王村调查，受此害虫危害，仅韩城市每年损失近几十万元。1形态特征1．1成虫雌蚧壳3mm左右，长形，后部稍大且稍弯，呈牡蛎状。蚧壳暗褐色或黑褐色，被一层灰白色粉粒。雄蚧壳小，约为雌虫的三分之一，呈一字形。1．2卵卵长0．27～037mm，椭圆形，乳白色。1．3若出若虫长0．33～0．38mm，体扁平，椭圆形，初乳白色，… 相似文献
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优良园林树种猴樟及其培育 总被引：5，自引：0，他引：5
本文对猴樟的优、特点进行了阐述，并对采种育苗和培育进行试验观测，结果表明猴樟1年苗平均高比香樟（C.camphora)和尾叶樟（C.caudiferum)分别高22．0cm和18．0cm，2年生苗比香樟、云南樟（C．glauduliferum)和尾叶樟分别高38．1cm，25．2cm和25．0cm，种子千粒重120－160g,每平方米最佳密度31－36株，5年生长大苗平均高4．63m，平均胸径6．8cm最大达9．8cm。 相似文献
6.
双条杉天牛生物学特性观察与无公害防治 总被引：5，自引：2，他引：5
双条杉天牛在济南1年发生1代，以成虫在被害树木蛀道内越冬，翌春3月上旬成虫开始出蛰，3月中、下旬进入出蛰盛期，3月底为末期；4月中、下旬幼虫大量孵化蛀入树干危害；8月下旬陆续化蛹，9月上旬为化蛹盛期；9月下旬成虫开始羽化．10月中旬为成虫羽化盛期，10月下旬为末期。成虫羽化期树干喷布200倍1％的绿色威雷Ⅱ号杀灭成虫，虫株率、虫口密度和受害死亡率较对照分别降低18．5％、2．5头，株和7．4％；林间设饵木引诱成虫产卵效果良好，受害率可降低3．4％；幼虫危害期林间释放管式肿腿蜂，寄生率较空白对照高47．3％以上；及时进行卫生伐，砍除受害树木，消灭虫源，对控制其危害起到较大作用，受害率可降低2．4％。 相似文献
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褐斑圆筒象（Ma0cr0c0rynusplumbeusF0r－manek）隶属象虫科害虫。1992年皖南宣州市麻姑山林场发现其成虫危害栗叶，对板栗生长、产量影响较大。近几年我们对该虫生物学特性进行了观察，并开展防治，现将结果报导如下。1分布与危害资料报道该虫分布在云、贵、川等省，经调查我省栗产区均有分布，江苏、浙江等地也有危害。其成虫啃食栗叶仅留叶脉，造成栗树生长衰弱乃至减产。据近几年观察，重害年份虫株率100％，单株最高虫口528头，栗叶损失量60％以上，减产3～4成。2形态特征成虫体长4．5～6mm，体宽2～2．5mm，细长筒形，黑色。体及触角… 相似文献
9.
板栗超补偿力的研究 总被引：1，自引：0，他引：1
板栗极易遭受剪枝栎实象Cyllorhynchites ursulus(Roel．)的严重危害，为探讨其危害损失程度，在舒城县城冲乡板栗林区，进行了模拟害虫危害和控制虫口自然危害试验。结果表明：板栗具有超补偿力。10a生板栗，疏苞率在5％～23％时，平均单粒增重量为0．4～2．4g之间，疏苞率在5％～17％时，平均单株增产2．41％～6．88％；疏苞率在19％～23％时，平均单株减产1．60％～6．36％；在22a生板栗林，控制单株雌成虫量在1～2头危害时，平均单株增产2．75％～5．39％，但在3～6头危害时，平均单株减产1．09％～24．30％。 相似文献
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青檀的栽培技术和利用 总被引：1，自引：0，他引：1
通过对青檀的育苗、造林、管理、利用等方面进行了一系列试验研究，结果表明：青檀可当年育苗、当年出圃。苗木平均高达1．05m，最高1．49m，平均粮径0．65cm，最大根径1．50cm，产苗量30．75万株/hm2。造林试验表明：在立地条件较好的情况下，5年生青檀平均高达6．24m，平均根径13．48cm，达到速生丰产要求。栽培和利用青檀具有明显的经济效益和社会效益。 相似文献
11.
《Scandinavian Journal of Forest Research》2012,27(5):427-435
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. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(3):206-217
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. 相似文献
13.
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. 相似文献
14.
Astra Zaluma Lauma Bruna Darta Klavina Natalija Burnevica Kristine Kenigsvalde Andis Lazdins Talis Gaitnieks 《Forest Pathology》2019,49(6)
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. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):118-130
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. 相似文献
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Steven Maranz Amadou Niang Antoine Kalinganire Djeneba Konaté Bocary Kaya 《Agroforestry Systems》2008,72(3):231-239
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. 相似文献
17.
《Wood material science & engineering》2013,8(2):76-84
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. 相似文献
18.
《Scandinavian Journal of Forest Research》2012,27(1):53-61
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. 相似文献
19.
《Scandinavian Journal of Forest Research》2012,27(1):15-27
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. 相似文献
20.
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。 相似文献