元谋干热河谷引种泰国赤桉效果好

元谋干热河谷引种泰国赤桉效果好杨成源，周宝康，王长福元谋属干热河谷地带，在这一地带造林难度极大。目前，能在这一地带造林的树种寥寥无几。经过试验，新引种的泰国赤桉在这里表现良好。泰国赤桉，是目前已报道的５个赤桉变种中的一个。它最初是由广东省引进的，“七...     

金沙江干热河谷能源林树种及其培育技术

以元谋干热河谷几种适应性强、生长快、薪材产量高、热值高的能源林树种为研究对象,在调查树种生态适应性基础上,比较了不同整地方式对造林效果的影响,同时对不同树种薪炭材产量和热能潜力进行比较分析。结果表明:元谋盆地为代表的金沙江干热河谷培育农村能源林,最适宜树种是赤桉(泰)、柠檬桉、赤桉、尾叶桉、新银合欢等,局部水肥条件好的地方可以选种大叶相思、马占相思等树种;这些树种均以撩壕整地的造林效果好于块状整地;各树种生物量及固定太阳辐射能的能力均以赤桉(泰)、柠檬桉、尾叶桉、赤桉和新银合欢较高。提出了在金沙江干热河谷地区培育农村能源林,应该选择赤桉、柠檬桉、尾叶桉和新银合欢等树种,采用容器育苗、撩壕整地、追施有机基肥、雨季初期取苗造林等综合配套的营造林技术。     

四川桉树适生种及栽培技术

根据四川省的气候和桉树的生物学特性 ,将四川省划分为盆地、攀西河谷阶地和干热河谷 3个栽培区。针对不同的栽培区 ,提出相应的适宜桉树种 ,并对巨桉、直干蓝桉、赤桉等树种的不同培育目标的栽培技术进行了总结。     

半干热石质山地墨西哥柏伴生树种选择研究

在云南省开远市浑水塘试验地设置了35个20 m×20 m的标准地,对标准地内4 a生的主要造林树种墨西哥柏及4个供选伴生树种（羽叶山黄麻、新银合欢、直干桉、赤桉）地径、树高、胸径、冠幅分别进行测量,选择平均木,对平均木生物量、生长量进行测定.经数据分析后认为,新银合欢生长速度慢于墨西哥柏且枝少叶疏,适宜作为墨西哥柏的伴生树种,羽叶山黄麻冠幅虽大,但枝叶稀疏,可作为墨西哥柏的次适宜伴生树种.     

元谋干热河谷相思树种和桉树类抗旱能力分析

对元谋干热河谷引种的8种外来树种进行了抗旱性分析，发现水分利用效率从高到低的顺序依次是：窿缘桉、赤桉、柠檬桉、绢毛相思、肯氏相思、厚荚相思、大叶相思、马占相思。水分利用效率越高，对干热环境的适应性越强。8种外来树种适应干热河谷生境的旱性结构的特点是主根深、侧根多、栅栏组织和贮水组织发达、构成等面叶或近等面叶。桉树类树种的蒸腾速率较高，但能生存的主要机理根系分布深，主动供水能力强，补充了地上部分的水分消耗；而相思类则以发达的根系和较高的叶片保水能力来适应干热环境。     

四川桉树基因收集及培育技术

经过近100年的引种历史,四川共收集了130余种桉树,目前仍保留有近40种桉树。这些树种在四川省的林业建设中发挥了重要作用。在四川具有发展前途的桉树有：巨桉、直干兰桉、柳桉、史密斯桉、邓恩桉、迪恩桉、亮果桉、赤桉、大花序桉、尤曼桉等。根据桉树生物学特性以及四川多年来桉树栽培情况,将四川桉树栽培地区划分为盆地、攀西河谷阶地和干热河谷等三个栽培区。针对不同的栽培区,提出相应的适宜桉树种,并对巨桉、直干蓝桉、赤桉树种不同培育目标的栽培技术进行了总结。     

元谋干热河谷区9种造林树种的水分生理特性比较

１９９３～１９９８年对元谋干热河谷区的９个造林树种的水分生理特性进行了观测。经对各观测树种水分状况、保水能力、蒸腾速率的分析对比表明：多数相思类树种主要通过减少叶子蒸腾耗水以提高其抗旱能力,蒸腾强度小有利于这些树种渡过旱季。乡土树种坡柳和桉类树种（除大叶桉）旱季蒸腾作用比较强烈,但离体叶片失水速度不快,它们具有特殊的水分平衡机制和较强的水分吸收能力,以此增强对干热河谷环境的适应性。此项研究为正确选择元谋以至金沙江干热河谷地区的适宜造林树种,以及人工林的水分管理措施提供了理论依据。     

云南省红河州石漠化治理树种叶的结构研究

通过石蜡切片和显微测量，研究了云南省红河州石漠化治理树种属内种间叶的结构及抗旱性的差异。结果表明：松属有2个指标存在差异，即表皮厚（马尾松-加勒比松〉细叶云南松）和下皮厚（加勒比松〉细叶云南松〉马尾松）；柏木属有2个指标存在差异，即总厚度和上表皮厚（均为墨西哥柏〉冲天柏）；按属有4个指标存在差异，即上角质层厚、下角质层厚、栅栏组织厚（均为赤桉〉直干桉）和海绵组织厚（赤桉〈直干桉）；金合欢属有6个指标存在差异，即总厚度、上表皮厚、下表皮厚、腹侧栅栏组织厚、背侧栅栏组织厚和贮水组织厚（均为肯氏相思〉大叶相思）。因此，如果仅从叶的结构来比较抗旱性，则松属中加勒比松〉马尾松〉细叶云南松；柏木属中墨西哥柏〉冲天柏；桉属中赤桉〉直干桉；金合欢属中肯氏相思〉大叶相思。     

玉溪大栗园人工混交林混交模型初步研究

用蓝桉、麻栎、藏柏、山樱桃、圣诞树、山合欢等作混交树种，在玉溪大栗园开展了8种人工混交林混交模型的试验研究，依据Ii=P1h/H+P2d/D+P3v／V计算混交模型的选择指标，用I标=I平均+aδn计算出混交模型的选择标准为3．0175。据此对参试的混交模型进行评定，结果以圣诞树×山樱桃带状混交效果最好，其次是藏柏×山合欢、藏柏×圣诞树带状混交。3种入选的混交模型的配置方式为混交林株行距为1m×2m的带状混交，混交林配置树种以50株为1行，4行200株为一混交模型，行与行随机排列。试验结果还表明混交林中各树种单株的生长量比纯林高。     

昆明地区荒山造林树种选择试验研究

本文根据昆明地区大面积宜林荒山的特点和课题的目的要求，进行了树种选择试验。通过试验，筛选出银荆、墨西哥柏、旱冬瓜、冲天柏、柳杉、藏柏、华山松、滇石栎、槲栎、麻栎等树种，可以在滇中宜林荒山造林中大面积运用。     

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.