川西高原青杨派杨树的地理类型

川西高原青杨派杨树的地理类型刘军（四川农业大学）在广阔的川西高原分布着极为丰富的青杨派杨树（Ｐｏｐｕｌｕｓｓｅｃｔ．ＴａｃａｍａｈａｃａＳｐａｃｈ），计有１０个种５个变种。高原及其与盆地过渡的高山峡谷区环境条件复杂多样，是杨树，特别是青杨派杨树适宜生...     

柠檬的茎尖培养和植株再生

试验以柠檬的嫩茎尖作外植体，通过组培育苗，培养出完整的柠檬瓶苗并移栽成活。最佳培养基分别为：改良ＭＳ＋６－ＢＡａ＋ＩＢＡｃ诱导茎尖；改良ＭＳ＋６－ＢＡｃ＋ＩＢＡａ培养不定芽增殖；改良ＭＳ＋ＩＢＡｃ＋ＡＢＴａ诱导生根。初次培养采用全暗条件；诱导、增殖阶段适宜温度２５±５℃；生根阶段适宜温度２０±５℃；培养基ｐＨ值均约５．８。结果表明：一个茎尖年繁殖系数为３１２个，移栽成活率达９０％以上。     

石栎净光合作用与环境因子的关系

分析了石栎（Ｌｉｔｈｏｃａｒｐｕｓｇｌａｂｅｒ）光合速率（Ｐｎ）与光强（Ｌ）、气温（Ｔ）和空气相对湿度（ＲＨ）在不同叶片类型、季节及全年几个水平上的相互关系,发现Ｐｎ与Ｌ正相关,在了（２５℃时Ｐｎ主要由Ｌ决定;Ｐｎ与了在２５℃上下分别为负相关和正相关,且Ｔ＞２５℃后了是Ｐｎ的主要限制因子;ＲＨ增加对Ｐｎ有促进作用,但关系较小,可忽略。不同类型叶片（阳生、阴生）对环境因子反应有较大差异。在一年中的绝大部分时间里,都能通过光照和温度的观测获得叶片光合速率的估计,在Ｔ＜２５℃时则可只用光照来预测光合速率。     

红豆杉属植物开发利用

红豆杉属植物开发利用①李大明龚长武孙耀青（河南省信阳林业学校信阳４５４１００）红豆杉科（Ｔａｘａｃｅａｅ）红豆杉属（Ｔａｓｕｓ）植物分布于北半球，全世界约有１１种，我国有４种和１变种，它们是西藏红豆杉（Ｔａｓｕｓｗａｌｉｃｈｉａｎｎｚｕｃｃ）、云南红...     

落叶松鳃扁叶蜂越冬幼虫地下分布抽样分析

；中部虫口数与总虫口的回归方程为；ｙ＝１３．３０９０＋２．６８３２ｘｒ＝０．８６３；外缘部虫口数与总虫数的回归方程为：ｙ＝６５．３３７４＋１．７３８３ｘｒ＝０．８３３６；垂直方向调查：枯枝落叶层内虫口数与总虫口数的回归方程为：ｙ＝７９．２１２７ｘ＋１．６６６７ｒ＝０．７０２１；距地表５ｃｍ以上土层内虫口数与总虫口数的回归方程为：ｙ＝４２．５２７０＋１．４７６８ｘｒ＝０．８９０１；距地表５ｃｍ以下上层内虫口数与总虫口数的回归方程为：ｙ＝１４５．７７５８＋１．６７３９ｘｒ＝０．５２９８；中部５ｃｍ土层内与总虫口数的回归方程为：ｙ＝５２．６２９０＋３．６３６９ｘｒ＝０．８２９０；３结果分析（１）落叶松鳃扁叶蜂越冬幼虫在树冠垂直投影下落叶层及土中分布无方向性，为随机分布。（２）从表１可见幼虫多分布于林冠下外缘部，中部次之而根基部附近较少。（３）从表２可见越冬幼虫以土中５ｃｍ以上分布最多，枯落层内次之而５ｃｍ以下土中分布较少。（４）在测报过程中调查虫口密度应以树冠垂直投影下中部５ｃｍ以上土层为调查对象，然后用回归方程求算单株虫口密度。（５）在充分摸清该蜂幼虫越冬场所和分布范围的基础上，可于秋季后至成虫羽化前采取人工收?     

棕肾圆盾蚧防治指标研究

本文组建了棕肾圆盾蚧Ａｏｎｉｄｉｅｌａｓｏｔｅｔｓｕ（Ｔａｋａｈａｓｈｉ）虫口密度与新银合欢Ｌｅｕｃａｅｎａｇｌａｕｃａ（Ｌ．）Ｂｅｎｔｈ枯枝率、枯枝率与木材损失率、林冠覆盖率分别与水土保持率间的一元回归模型、林冠覆盖率及年平均降雨量分别与水土保持量间的二元回归模型，确定了林冠覆盖率和水土保持量临界值以及木材年生长量、等于防治成本的水土损失以及木材损失和相应允许的林冠覆盖率损失，在此基础上，以改进的经济阈值模型：Ｃ＝∑ｎｉ＝１∑ｋｊ＝１（ＰｉＲｊ）·Ｄ·Ｆ，求出７０％、８０％及９０％林冠覆盖率下该虫的防治指标分别为：２．５９、１５．０２、２７．４４头／ｃｍ２。     

大兴安岭落叶松毛虫的卵寄生蜂（膜翅目：细蜂总科,小蜂总科）

调查发现，大兴安岭落叶松毛虫ＤｅｎｄｒｏｌｉｍｕｓｓｕｐｅｒａｎｓｓｉｂｉｒｉｃｕｓＴｓｃｈｅｔｖｅｒｉｋｏｖ共有５种卵寄生蜂（其中包括１个新种）。它们的总寄生率达５４．６３％（±１．７０％），在自然控制这种害虫上发挥着重要作用。同时，对５种卵寄生蜂作了较为详细的形态描述，并对一些误名作了更正。这５种卵寄生蜂为：落叶松毛虫黑卵蜂ＴｅｌｅｎｏｍｕｓｔｅｔｒａｔｏｍｕｓＴｈｏｍｓｏｎ（细蜂总科）；松毛虫卵宽缘金小蜂Ｐａｃｈｙｎｅｕｒｏｎｓｏｌｉｔａｒｉｕｍ（Ｈａｒｔｉｇ），松毛虫迈金小蜂ＭｅｓｏｐｏｌｏｂｕｓｓｕｐｅｒａｎｓｉＹａｎｇｅｔＧｕ（新种），落叶松毛虫卵跳小蜂Ｏｏｅｎｃｙｒｔｕｓｐｉｎｉｃｏｌｕｓ（Ｍａｔｓｕｍｕｒａ）和松毛虫赤眼蜂ＴｒｉｃｈｏｇｒａｍｍａｄｅｎｄｒｏｌｉｍｉＭａｔｓｕｍｕｒａ（小蜂总科）。     

木霉对苗木土传病原真菌的拮抗作用

体外测定表明，木霉菌株Ｔ—１６９和Ｔ—２７９对病原菌Ｒｈｉｚｏｃｔｏｎｉａｓｏｃｌａｎｉ（立枯丝核菌）、Ｆｕｓａｒｉｕｍｏｘｙｓｐｏｒｕｍ（尖孢镰刀菌）、Ｐｙｔｈｉｕｍａｐｈａｍｉｄｅｒｍａｔｕｍ（腐霉）和Ａｌｔｅｒｎａｒｉａｔｅｎｕｉｓ（交链孢霉）在对峙培养中的拮抗系数分别为２、２～３和３。温室测定表明，用０．６％（Ｗ／Ｗ）Ｔ－１６９麸皮培养物（１０７ｃｆｕ／ｇ）处理土壤。在人工接种立枯丝核菌、尖孢镰刀菌、腐霉及交链孢霉２０ｄ后，落叶松苗木发病率分别比未用木霉处理的对照减少４９．６％、１７．４％、１８．３％和１１．７％；用Ｔ－１６９和Ｔ－２７９木霉孢子悬浮液（１０８ｃｆｕ／ｍｌ）处理落叶松种子，人工接种立枯丝核菌１９ｄ后，落叶松成苗率分别比未用木霉处理的对照增加１８．８％和１２．７％。     

肉花卫矛种子休眠及其解除的研究

＞Ｆ０．０１＝５．９９）。经ＬＳＲ检验，变温层积（２０～２５℃４５ｄ＋２～５℃　４５ｄ）的发芽率最高，可达５６．７％，且与其它各层积处理的发芽率之间存在极显著的差异；２～５℃层积９０ｄ、７０ｄ及对照（２～１５℃层积９０ｄ）的种子发芽率之间差异不显著；２～５℃层积３０ｄ的发芽率最低，仅为２２％（表２）。以上试验小结为：（１）成熟且发育完善的肉花卫矛种子在适宜的温度、水分等条件下不能发芽，种皮透气性差是肉花卫矛种子休眠的原因。（２）层积处理可以提高种子的发芽率，其中以２０～２５℃４５ｄ＋２～５℃４５ｄ变温层积处理的发芽率最高，可达５６．７％，解除了种子休眠。     

西伯利亚落叶松嫩枝扦插育苗技术研究

西伯利亚落叶松扦插较难生根，１９９２～１９９３年在哈密林木良种基地进行了全光喷雾嫩枝扦插育苗试验。结果表明，以锯末为扦插基质，用１．５ａ生西伯利亚落叶松嫩枝扦插，平均生根率达到８０．３９％；平均生根数量５．８６条，每穗平均根长１．７８１ｃｍ。初步认为，提高西伯利亚落叶松幼龄母树嫩枝扦插生根效果的最佳组合是：锯末（基质），扦插密度２ｃｍ×４ｃｍ，生根粉（ＡＢＴ）５００μｇ／ｇ，插条长度８～１０ｃｍ。     

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.