白花草木樨改造紫色石骨坡初报

紫色石骨坡既是造林绿化的难关,又是急待开发的国土资源。解放以来,群众对紫色石骨坡采取挖大窝、打撩壕或爆破等方式,栽植了柏木、刺槐、马桑、芭茅、柑桔和黄桃,虽取得了一定成绩,但花工量大、成效不佳,或因财力不足,很难推广。白花草木樨(Melilotus albus Desr)属豆科两年生草本,茎直立,高1～4米,全草有香气,适生于湿润和半干燥气候,为家畜重要饲料,可作绿肥、护地作物和燃料,根有很强的穿透力,能改善石骨母质的适生条件。1988年底,我市从外地引入白花草木樨种子,1989年开始对无土石骨荒坡进行直播试验。     

"三岩"造林困难地植被恢复技术研究与示范

湖南造林困难地类总面积达 10 0万hm2 。通过对 5个县 658hm2 试验示范林历时 9年的研究 ,解决了植被恢复技术问题。选出适宜的树、划种有马桑、芦竹、苦槠、牡荆和栓皮栎 5种 ,有发展前景的树种有柏木、铅笔柏和藏柏。选出了林分结构稳定 ,组成种长势好 ,可以肯定的有马桑十墨西哥柏浅层钙质幼年性岩性土等 6个配置模式。并提出和推广了撩壕整地和芦竹下挖上堆 ,施肥促长等造林技术。同时 ,定义了“三岩”造林困难地 ,提出了“三岩”造林困难地的生态环境特点。从土种的水平研究了树种与立地的适应性。     

裸露石骨子山马桑、柏木造林试验

在安岳县的裸露石骨子山进行了埋条马桑穴内栽植柏木的造林试验。结果表明,在栽植马桑的穴内营造柏木混交林成活率高,是治理裸露石骨子山的有效途径。埋条马桑穴内栽植柏木能显著改善土壤养分状况,有利于加快林木生长。造林时间以6月或9月~10月为宜。     

长江上游地区林业生态建设与治理模式(续)

<正> 6.8 农村能源开发薪炭林治理模式6.8.1 技术思路 在农村人口稠密,缺少煤炭、天然气等燃料的地方,合理布局薪炭林。薪炭林以选择萌生能力强、热值高、生物量大的树种为佳,解决当地烧柴问题,同时辅以改灶节柴等措施,与农村能源开发相结合。6.8.2 主要技术措施 (1)主要树种 麻栎、栓皮栎、刺槐、紫穗槐、黄荆、马桑、桤木、槲栎、柏木、马尾松等。     

川中丘陵区优良适宜树种选择

首先选用生长适宜性指标、抗逆性指标、生态功能指标作为控制层,生长周期、更新能力、生长速度、抗旱性、抗寒性、耐瘠薄性、冠层疏透性和根系特性等8个因子作指标层,用层次分析法对柏木、马尾松、桤木和香樟等20个供选树种进行模型选择,然后对得分较高的树种分别在川中丘陵区的柏木纯林、马尾松纯林、松柏混交林中进行改造后的栽培对比试验。结果表明:(1)模型筛选出适宜川中丘陵区的乔木树种分别为麻栎、栓皮栎,刺槐,桤木,喜树,香椿,马尾松、香樟、柏木9个,灌木树种为马桑,黄荆,火棘3个。(2)从成活率、保存率和生长状况分析,香樟、桤木、喜树、窄冠刺槐、香椿均可用于在柏木纯林中补植,立地条件较好的地块以补植香椿为宜,立地条件差的林分中以补植窄冠刺槐为宜。马尾松纯林中应补植香樟和栓皮栎,但补植香樟时应选择土层较厚,土壤含水量较高的林分。补植的苗木以2a生大苗为宜。     

春风吹绿三难地

初夏的湘南，万木争荣，昔日凄凉的不毛之地，如今披上了绿装。芦竹、马桑、刺槐郁郁葱葱，就连春造的苗木也不甘寂寞，绽放了新芽，呈现勃勃生机。据统计，去冬今春衡阳市共完成“三难地”改造任务1.27万公顷，其中人工植苗8266.67公顷，封山育林4433.33公顷。2001年底，退耕还林正式在衡阳全面启动，给“三难地”改造带来了新的契机。为了彻底解决制约衡阳林业发展，影响社会经济建设和发展形象的“三难地”问题，市委、市政府研究决定，“三难地”改造要以退耕还林等生态工程为依托，退耕还林要在紫色页岩生态脆弱区重点铺开。同时，作出…     

石漠化区枫香、刺槐和柏木的抗逆性初步研究

于不同程度石漠化区的枫香、刺槐和柏木人工林中采集叶片为试材,通过比对3种植物叶片中叶绿素、SOD、丙二醛(MDA)和脯氨酸含量的变化,对石漠化区3种植物抗逆性进行分析评价。结果表明:不同石漠化程度区对植物体内SOD含量的影响显著。在轻度石漠化区,柏木SOD含量最高,刺槐SOD含量最低;在中度石漠化区,柏木SOD含量最高,枫香SOD含量最低;在重度石漠化区,枫香SOD含量最高,刺槐SOD含量最低。刺槐叶片MDA含量与叶绿素含量呈显著负相关,而柏木叶片MDA含量与叶绿素含量则呈显著正相关。     

川中农区人工柏木幼林生长与立地条件人为措施的关系

柏木是川中农区的重要用材树种,适应性强,天然分布广,纯林多,也有与桤木、黄荆、马桑等混生.柏木冠幅小,材质优良,川中农民有悠久的栽培历史,在田边、地坎、丘陵荒坡广泛种植.其缺点是比松杉等树种生长较慢.     

杉木根干馏油提取杉木精油及化学成分分析

本实验先通过水蒸气蒸馏后减压蒸馏法，从杉木根干馏油中分段提取出杉木精油，并用GC、GC-MS对提取物进行了定性定量分析。分离出30个色谱峰，共鉴定出25个化合物。其中，水蒸气蒸馏部分的精油中主要含α-蒎烯11．88％、α-松油醇3．97％、α-柏木烯35．03％、β-柏木烯8．62％、柏木脑11．76％；减压蒸馏部分的精油中主要含α-柏木烯18．02％、β-柏木烯15．94％、柏木脑52．51％，精油经重结晶提纯得柏木脑，并对其进行了红外光谱和核磁共振氢谱分析。     

古蔺县赤水河流域干热河谷造林经营技术试验

选择古蔺县赤水河流域干热河谷三种树种:刺槐、新银合欢、柏木进行造林经营技术试验,初步得出以刺槐作为赤水河流域干热河谷造林的先锋树种较为适宜,柏木次之,新银合欢营养袋苗还有待进一步观察。     

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.