山西省生物防火林带营造技术

笔者从防火林带建设原则、布设位置、生物防火树种选择、林带建设类型等方面阐述了生物防火林带营造技术,又从造林、抚育管护2方面介绍了防火林带的造林抚育技术。最后提出了建议,以期为今后山西省生物防火林带建设提供参考。     

广西雅长林场防火林带树种选择与密度确定方法

营建生物防火林带是预防森林火灾蔓延、减少经济损失的有效方法，科学地选择防火树种和合理确定林带密度则是营建生物防火林带的关键。以广西国有雅长林场为研究对象，提出了基于理想点评价方法的防火树种选择和地理信息系统支持下的防火林带密度确定方法，结果表明：借助于现代决策方法与地理信息系统技术，可使防火树种的选择和林火阻隔网合理密度确定更为科学、客观、合理。     

建设山西省生物防火阻隔网的探讨

分析了山西省生物防火林带建设现状,提出了山西省生物防火林带建设存在思想认识不到位、防火树种单调、生物防火林带建设标准低、生物防火林带布局不合理、生物防火阻隔网建设不健全、建设资金投入不足等问题.从建立完善生物防火林带"四同步"机制、加强生物防火树种的选育、科学建设生物防火林带、加强生物防火林带的抚育管护、形成生物防火阻...     

防火林带树种筛选研究

防火林带树种筛选的研究是生物防火工作的重点内容之一。该文对浙江省绍兴地区木荷等18个常绿阔叶树种树叶的7个抗火性能相关指标(包括含水率、发热量、粗脂肪含量、苯-乙醇抽提物含量、燃点、粗灰分含量、叶燃烧速度)进行了测定和模糊聚类分析,认为木荷、杜英、红楠、金叶含笑和女贞等5个树种的抗火能力较强,可在浙江省绍兴地区适宜作为生物防火林带的首选树种加以推广。     

连城县经济树种型(油茶)生物防火林带及效益分析

指出了生物防火林带建设是森林防火关键的基础性工作,是预防和控制森林火灾的一项治本措施。提高森林火灾预防和控制能力的一个非常重要的方法就是生物防火林带的营建,在连城县现有多类型的生物防火林带建设中,油茶生物防火林带是一种既有良好防火作用,又有比较显著经济效益的优良生物防火林带,同时连城县的自然环境也非常适合油茶防火林带的营建。以连城县姑田镇经济树种型(油茶)生物防火林带建设为例,探讨了油茶防为材带营造技术措施,分析了油茶防为林带的营建效益,以期提供参考。     

生物防火林带营建技术

根据浙江省生物防火林带实际,总结和探讨了针对山脊、山脚田地边、墓地周围、林内不同位置、道路等地段在较短时间内产生防火效果的防火林带营建技术,介绍了生物防火林带改建技术和对现有防火林带的培育及经营措施。     

木荷防火林带群落及其不同立地生长特性研究

对千岛湖地区不同林龄和立地条件的木荷防火林带的群落与生长特性的调查研究表明:随着木荷防火林带林分年龄的增加,易燃的蕨类逐渐减少,低矮耐阴的小草本和灌木树种甚至目的树种渐渐增多,但防火林带依然是单层优势群落,群落垂直结构较差;不同的立地类型对生物防火林带树种的生长影响较大,随着土层厚度降低、坡度加大、土壤石砾含量增加,防火林带各树种的高生长和径生长减少;木荷速生期出现在5~10年生时,年平均材积生长量达4 m3.hm-2以上;木荷树冠高大,叶子浓密、革质、含水率高达69%。木荷适宜在千岛湖区生长,可用于营造防火与用材两用林。     

浙南山区生物防火阻隔林带营造技术试验

通过生物防火林带结构模式的研究,对泰顺县火灾现场进行实地调查后,研究和分析常绿阔叶林中不同植物种类的抗火性、耐火性和燃烧性,筛选出用于生物防火林带建设的植物种类,并进行生物防火林带造林试验、结构与配置、造林规格及位置的研究.试验表明,由乔木-亚乔木-灌木构成复层结构,配置境界、主、副防火林带,结合山脊、山谷位置的防火林带,能达到理想的生物防火效果;对木荷、杨梅、茶叶等17个树种进行枝叶含水量和抗燃时间的测定的结果表明,杨梅、木荷、女贞、山杜英、甜槠、广玉兰、红花油茶、油茶、茶叶等树种可选为生物防火林带造林,其防火和阻燃性能比较理想.开展生物防火林带造林,经检查造林保存率与成活率均在85%以上,幼树生长良好     

生物防火林带营造技术及效益分析

根据厦门市同安区多年来生物防护林带建设实践,总结生物防火林带的布设、结构设置、树种选择与配置、营造林等营建系列技术,并对生物防火林带的防火效益、经济和生态效益进行分析探讨,为建设高效的生物防火林带提供参考。     

山西省林业科学研究院

正山西省生物防火林带构建技术研究完成单位:山西省林业科学研究院内容简介:提出了山西省生物防火林带建设中防火树种选择、防火林带宽度和结构、山西省生物防火林带营造模式的关键技术。对山西省30个主要造林树种的理化性质指标和生物学、生态学特性指标数据,采用层次分析法进行综合评判排序,数量化划分了各树种的防火能力。通过     

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。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

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.     

Risk Perception Among Non-industrial Private Forest Owners

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.     

Interactions in decomposition and N mineralization between tropical legume residue components

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.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

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.