森林生态系统管理科学中的生态采伐技术研究进展

在总结大量国外献基础上，对森林经营的理论基础－森林生态系统发育模式，森林生态系统管理的新技术体系－以结构为核心的森林生态采伐技术做了详细的论述，章提出对于森林生态系统管理科学的学习和借鉴，将有助于我国开展天然林保护和林业生态工程建设。     

ERS—1SAR影像森林应用研究初探

本研究利用１９９２年成像的覆盖山东省烟台地区的ＥＲＳ－１ＳＡＲ和ＴＭ资料开展工作。研究中首先将这两种遥感资料进行了几何精纠正和与地形图的配准，尔后，用典型相关分析法对遥感资料与森林参数间进行了相关分析研究，结果表明，Ｃ波段的ＥＲＳ－１ＳＡＲ资料与森林冠层厚度和平均树高相关程度较高；森林参数综合因子对ＥＲＳ－１ＳＡＲ影响大于对所用ＴＭ波段的影响，说明ＥＲＳ－１ＳＡＲ资料在森林应用中，对森林参数乃至于     

卫星林火监测及信息传输有关问题的探讨

卫星林火监测、计算机网络在森林防火工作中的应用，提高了森林防火工作的科技含量，为森林防火提供了更可靠的监测和信息传输手段，但也出现了一些需要进一步研究和解决的问题。１　卫星林火监测及其信息的应用１．１　卫星林火监测卫星林火监测是近几年发展起来的一项先进的森林火灾监测手段，是利用目前在轨运行的ＮＯＡＡ系列气象卫星，即ＮＯＡＡ－１２、ＮＯＡＡ－１４、ＮＯＡＡ－１５（将用来替代ＮＯＡＡ－１２）组成的双星系统实现对森林火灾的适时监测，两颗星上下午正交运行，可覆盖全球的绝大部分地区，对同一地区每天至少能提…     

森林防火的足迹

广西是我国南方林业大省之一，也是全国森林火灾多发省区之一。改革开放20年来，在各级党委、政府的领导下，森林防火事业有了很大的发展，预防和扑救森林火灾的综合能力有了很大提高，森林火灾逐年大幅度减少，森林火灾次数从1954－1978年的年均1820次，减少到1979－1998年的年均1080次；森林受害面积从年均52384公顷，下降到28441公顷。回顾改革开放20年来森林防火工作的进步，主要得益于以下几个方面。1．农村改革开放取得的巨大成就是森林火灾大幅度下降的根本原因我区85％以上的森林属于农民集体和个人所有，森林火灾绝大部分也发生在…     

ERS－1SAR影像森林应用研究初探*

本研究利用１９９２年成像的覆盖山东省烟台地区的ＥＲＳ－１ＳＡＲ和ＴＭ资料开展工作。研究中首先将这两种遥感资料进行了几何精纠正和与地形图的配准，尔后，用典型相关分析法对遥感资料（ＥＲＳ－１ＳＡＲ、ＴＭ３、ＴＭ４和ＴＭ７）与森林参数（包括平均树高、胸径、枝下高、冠层厚度和郁闭度）间进行了相关分析研究，结果表明，Ｃ波段的ＥＲＳ－１ＳＡＲ资料与森林冠层厚度和平均树高相关程度较高；森林参数综合因子对ＥＲＳ－１ＳＡＲ影像的影响大于对所用ＴＭ波段的影响，说明ＥＲＳ－１ＳＡＲ资料在森林应用中，对森林参数乃至于森林蓄积量的估测是有潜力的。     

我区今年9-10月份森林火灾大幅度减少

进入秋防季节以来，我区森林火灾与上年同期相比，无论是发生次数还是受害面积都有较大幅度下降。全区9－10月森林火灾次数为23起，比去年减少了121起，下降了84％；受害森林面积为98．3公顷，比去年减少了2474公顷，下降了96％。今年9－10月份工作取得如此好的成绩，主要是做好了：1．早部署、早安排。自治区森林防火指挥部及时召开了第24次成员扩大会议，分析了秋冬防形势，部署工作，提出了具体要求。各级党委、政府、森林防火指挥部门高度重视，采取措施，确保森林防火各项措施的落实。2．做好预测预报工作。区森林防火指挥部积极发挥职…     

河北省森林火灾形势分析与对策

在对河北省林林火灾调查的基础之上，分析了从1950－1991年的森林火灾，并讨论了防治对策。以推动河北省森林火灾的实践研究     

减少林地死可燃物在森林防火中的作用

减少林地死可燃物在森林防火中的作用赵顺昌（－）减少林区死可燃物的重要性１９８７年大兴安岭特大森林火灭以来，全省各级领导都一分重视森林防火工作，重点市县乡（镇）场按照要求组建和强化了护林防火组织和护林队伍，开展了广泛的森林防火宣传，重点进行了护林防火基...     

82-3型森林化学灭火剂地面搅拌设备的防腐方法

日前，我国在东北大、小兴安岭林区已经利用Y-五型、M－18型飞机喷洒82－3型森林化学灭火剂扑灭森林大火。由于82-3型森林化学灭火剂需要在由钢铁制成的地面搅拌设备中配备制成并储存其中。然而，由钢铁制成的82－3型森林化学灭火剂地面搅拌设备在使用和闲置时易生锈腐坏，如不注意保养，采取一定措施，长期使用下去会造成严重腐蚀，直至不能使用。因此，为了不使国家财产遭受损失，延长82－3型森林化学灭火剂地面搅拌设备的使用寿命，应充分重视设备的防腐工作。1设备的腐蚀原理1．1化学腐蚀钢铁与外界物质直接发生化学反应而引起的腐蚀叫…     

燕山东段森林群落及灌木群落枯落物的研究

燕山东段森林群落枯落物现存量平均为４．３５－２８．６７ｔ／ｈｍ＾２，以山杨混交林、松栎混交林、椴树混交林最高，栎林和油松林次之，侧柏林最低。灌木群落枯落物现存量平均为４．１５－１８．９４ｔ／ｈｍ＾２，低于森林群落。森林枯落物现存量受树种组成、年龄、立地条件及人为干扰的影响。其中，人为干扰影响最大，几乎使枯落物损失殆尽。森林枯落物营养元素总贮量０．１７６－１．５３４ｔ／ｈｍ＾２，最大贮水量３．９－５     

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.