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1.
综述了国外制材工业三个发展阶段的特点以及四种主要制材模式的发展情况及优缺点,通过与世界制材发达国家的对比,找出了差距,认为我国大部分制材企业还处在传统制材阶段,存在制材模式与经营模式过于单一、设备与原木加工径级不匹配等问题。针对我国制材工业的现状,认为我国制材行业必须向数控最优制材发展,因地制宜发展圆锯制材、削片制材与框锯制材,并转变经营模式,只有这样才能走出困境。  相似文献   

2.
综述了国外制材工业的三个发展阶段的特点以及四种主要制材模式的发展情况及优缺点,通过与世界制材发达国家的对比,找出了差距,认为我国大部分制材企业不处在传统制材阶段、存在制材模式与经营模式过于单一、设备与原木加工径级不匹配等问题,针对我国制材工业的现状,认为我国制材行业必须向数控最优制材发展,因地制宜圆锯制材发展,削片制材与框锯制材,并转变经营模式,只有这样才能走出困境。  相似文献   

3.
世界制材工业现状及发展趋势   总被引:1,自引:0,他引:1  
本文概述了世界制材工业现状,从林木资源利用、提高锯材质量、完善加工工艺、开展小径木加工,采用高新技术等方面,介绍和论述了世界制材工业的发展趋势。针对我国制材工业的现状和存在的问题提出了解决对策。  相似文献   

4.
中国木材工业现状与未来   总被引:4,自引:3,他引:4  
从木材资源与市场、人造板工业、木地板、制材工业等方面,叙述了中国木材工业的现状,并指出了该行业的发展趋势,对未来作出了积极地展望。  相似文献   

5.
中、小径级原木制材工艺的探讨吴万荣,丁廷文(黑龙江省林产工业研究所)(东北林业大学)1目标我国目前中、小径级原木制材工艺的发展目标是围绕提高制材工业水平,侧重提高锯材出材率、加工规格质量和木材利用率,研制出适合我国国情的削片制材新工艺,并以此作为示范...  相似文献   

6.
目前就世界范围来说,有三种不同的制材方法,即框锯、园锯、带锯制材。除此之外,又增加了第四种制材设备,这就是原木削片制材联合机,这种联合机械可以说是木材综合利用工业(制材、造纸、纤维板和刨花板工业)发展的必然结果。本世纪中叶,制材技术同其它许多工业领域一样,进展较为缓慢,1950年后显得发展较为迟缓,主要是平稳地前进而缺乏或甚至很少有跃进局面。明显的是受制材机械的发展水平所限制,  相似文献   

7.
目前我国制材工业与技术先进国家比较,仅是50年代的水平。就国内来看,同电子、机械工业相比,也是落后的;我国制材工业,除少数大厂,多是设备陈旧不配套,产品质量低,经济效益差。根据上述情况和我国森林资源的现状,综合国内外制材工业的先进经验,对制材跑车进行了改进设计。一、旧制材跑车的缺点1、车体短而窄,车上有三个车桩,对  相似文献   

8.
张守政 《林业科技》1994,19(2):1-3,5
我国制材工业的回顾和发展张守政(黑龙江省林业科学院)1我国制材工业的回顾我国制材生产有着悠久的历史,在漫长的岁月中一直是手工制材,而机械制材只是在本世纪才开始。1905年英国在上海、广州等口岸建立了小规模的以圆锯为主的制材厂,之后在沿海一带也相继建起...  相似文献   

9.
一、前言制材是木材加工工业的基础。搞好制材生产对于扩大森林资源的利用,提高木材利用率具有重要意义。影响制材产品的主要因素是制材工艺和机械设备。当前我国制材工业的技术装备是比较落后的,它直接导致了制材产品质量低劣,据有关部门统计,制材产品合格率仅达70%左右。  相似文献   

10.
制材设备的发展及趋势   总被引:1,自引:0,他引:1  
笔者从世界各国森林资源状况、制材产品和制材工艺技术发展的角度,围绕世界制材行业高生产率、高出材率、高木材利用率、高成材质量、高附加值和多产品品种的发展特点,分析了制材设备的发展及趋势:1)传统制材设备向数控化、智能化方向发展;2)为满足森林资源和制材产品变化,制材设备向多样化发展;3)为适应制材工艺技术的发展,制材设备向柔性化、创新化发展。这将为我国木材资源的高效利用和制材工业又好又快的发展提供有益借鉴。  相似文献   

11.

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.

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.

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   

14.

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   

15.
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   

16.

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.  相似文献   

17.
18.

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.  相似文献   

19.
In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.  相似文献   

20.
The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha−1 target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha−1. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1); (2) Lolium perenne L. var. Tove (25 kg ha−1) + Trifolium repens L. group Ladino (4 kg ha−1) + Trifolium pratense L. var. Marino (1 kg ha−1). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m2, with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

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