湛江红树林的保护策略

文章对湛江红树林的保护策略进行了探讨,提出要站在发展湛江及邻近地区大农业的高度上来认识保护湛江红树林的重要性;提出要就地保护好现有的１２４２３ｈｍ＾２的红树林及适宜其生长滩涂的具体措施;开展迁地保护和引种红树林遗传种质资源,为发展当地经济作贡献;建议成立“湛江红树林研究中心”和“湛江市生物多样性保护委员会”,切实做好湛江红树林的保护和合理开发利用工作。     

广西钦州市红树林造林研究

结合钦州市红树林示范项目造林现状，于2012年3月对钦州市滩涂造林点的7个红树林小班进行保存率（成活率）、高度、地径、叶片数等指标的调查。针对海浪、气候、人为活动、垃圾及藤壶附着物等因素对红树林幼苗生长的影响进行初步分析。提出加强对红树林的管护、及时补植等提高造林成效的对策措施，并总结出注意造林地的选择、选择适宜本地生长的耐寒性树种等造林经验，以促进红树林资源的恢复和发展。     

红树林生长气象条件适宜度评估方法研究——以广西北海沙生红树林为例

定量化评估气象条件的影响可为红树林保护和修复提供重要决策依据.以广西北海典型沙生红树林为对象,利用北海红树林生态气象站观测数据、红树林植被指数和国家气象台站数据,研究影响红树林长势的关键气象因子、红树林小气候效应和气象指标阈值,建立红树林综合气象条件适宜度评估模型.结果表明,气温、降水量、相对湿度和风速为影响广西北海红树林生长的关键气象因子.红树林小气候效应明显,气象适宜度评估需对风速资料进行订正.采用生育期有效积温、累积降水量、相对湿度和风速作为评估指标,采用打分加权法,建立红树林综合气象条件适宜度评估模型,气象适宜度评估结果与红树林长势变化有较高的一致性.     

水东湾红树林湿地生态旅游SWOT分析及开发策略

红树林湿地是沿海地区开展森林游憩和生态旅游的重要资源,科学地经营水东湾红树林是当地绿色经济发展中必须着重考虑的问题。SWOT分析表明：水东湾红树林湿地在自然条件和地理区位上具有开展生态旅游的明显优势,但同时也存在着局部污染严重、基础设施落后以及景观单调的劣势。水东湾红树林湿地生态旅游开发应抓住生态文明建设的发展机遇,克服开发与保护之间的矛盾,采取有效的管理措施,建设服务功能强大的生态旅游景区。     

番禺地区引种种植红树林的研究

试图从理论和实践上解决6广东翻禺地区人们一直关心的“可否利用当地滩涂构建多用途的生态公益红树林体系”的问题，提出了在构建过程中的合理化建议，首先从多个理论角度论证在广东番禺地区引种种植红树林可以取得成功，然后通过在3个地点营造4个树种、遍布14.2km长的潮滩带、总面积达13.7hm^2的试验林进行实际检验，结果表明：实际试种检验结果与理论分析结论基本吻合，几个树种的保存率和生长情况与我国其它红树林主要分布地区相同树种的情况相当；适宜当地发展红树林的较佳树种为无瓣海桑、秋茄和木榄，适合它们生存的滩面高程分别为相对于海平面-0.8m,-0.74m和-0.43m以上。本文可作为当地有关政府部门发展红树林的一个决策依据，同时，也可为珠江三角洲沿岸抗议红树林提供参考。     

温州沿海海涂秋茄红树林引种造林及开发前景

秋茄红树林是自然分布于福鼎以南的热带，亚热带海洋的适盐性树种，通过人工引种，可以改变温州海涂造林树种少的问题。温州滩涂资源丰富，环境条件较适宜秋茄红树林生长，而且目前已形成人工引种造林技术体系，通过秋茄红树林引种造林，可以发挥它良好的防护功能和风景观赏作用。     

3种修剪方式对大枣生长的影响

辽宁阜新气候干旱,"两杏一枣"的引进对该地区的环境改善和经济提升有较好的效果。以朝阳大枣为研究对象,研究3种冬季和夏季结合的修剪方式对当地大枣生长的影响。结果表明:不同的修剪处理对大枣枝条粗度、叶绿素含量和叶面积都有不同程度的影响,都以C处理的修剪方式最好,适宜在当地推广。     

早实核桃品种引种初步观察

对引进的22个早实核桃品种在当地生长结实特性、越冬表现、抗病性以及坚果经济性状进行了初步调查分析。结合当地核桃栽培条件,初选出了几个适宜在省内推广的品种,进行区域栽培试验。     

红树林人工恢复造林技术初探

随着社会经济的不断发展,人们对生活环境的要求也越来越高,而红树林可以起到防浪、净化海水、维护生物多样性的作用,由于其生长在热带以及亚热带沿海地区,所以对于沿海地区的人们来说,恢复红树林植树造林是非常重要的。但是在实际的生活中,红树林的面积逐渐减少,功能逐渐下降,同时给人们的生活质量也带来了极大的影响。基于此,本文通过对红树林人工恢复植树造林技术作详细的研究和探讨。     

关于湿地公园游憩功能分类的探析

文章通过从多角度对游憩活动的类型进行探讨,对湿地公园的功能进行分析,结合游憩活动的分类提出了"湿地公园游憩功能的分类",将湿地公园游憩功能分为六个大类、十二个小类,并列出相应内容。     

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.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

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。     

Growth of Mixed Birch-Coniferous Stands in Relation to Pure Coniferous Stands at Similar Sites in South-eastern Norway

Mean age, mean and top heights and yield were studied in 20 mixed stands of birch ( Betula pubescens Ehrh. and B. pendula Roth) and Picea abies (L.) Karst. and nine mixed stands of birch and Pinus sylvestris L. in south-eastern Norway. Each mixed stand and the adjacent pure coniferous stand (control) were growing under the same site conditions and had not been commercially thinned. There were no significant differences in mean age at breast height or in top heights between birch and conifers in the mixed stands, while mean height was significantly higher for birch than for spruce. A growth index was calculated based on total volume and age at breast height. For the spruce sites the growth in young mixed stands (birch < 17 m) was superior to that of pure spruce, while the difference was insignificant in older stands. The growth index correlated positively with the ratio between generatively and vegetatively regenerated birch trees, and negatively with the age of the oldest species in the mixture and with site quality. For the pine sites there was no significant difference in the growth index between mixed birch-pine and pure pine stands. A mixture effect of birch on the volume yield of spruce or pine could not be demonstrated.     

Defoliation by the Needle-shortening Pine Gall Midge,Thecodiplosis brachyntera,on Pines in Central Sweden

An outbreak of the needle-shortening pine gall midge, Thecodiplosis brachyntera , occurred on Scots pine, Pinus sylvestris (L.) and lodgepole pine, P. contorta (Dougl.) in central Sweden during 1995-1998. The larval feeding of T. brachyntera kills current-year needles and heavy infestation causes severe defoliation. A pattern of fluctuating defoliation among years and sites was found on both pine species. Defoliation was evenly distributed in the crown of P. sylvestris during years of high as well as low infestation; apical whorls had as much defoliation as basal whorls. In P. contorta , however, there was a tendency for defoliation to be concentrated on branches in the most apical whorls. Growth ring increments on P. sylvestris with high levels of defoliation (71%) did not differ from trees with moderate levels (26%) of defoliation. Shoot lengths were significantly shorter, however, on heavily infested trees the year after defoliation.