秋色叶树种变色机理及应用

秋色叶树种是指那些每年秋季树叶变色均匀一致,持续时间长,观赏价值较高的树种,如枫香、黄栌、鸡爪槭、银杏等。秋色叶树种多为温带落叶树种,极少数为常绿树种,如石楠、南天竹等。尽管温带落叶树种在秋季都有变色现象,但绝大多数树种不是持续时间短就是缺乏观赏性而不能被称为秋色叶树种。     

黑龙江省秋色叶树种资源调查及园林应用中的问题

调查黑龙江省秋色叶树种资源,筛选出可作为城市园林绿化的树种并描述其主要种的特征与观赏价值。探讨了在园林应用中的注意问题,为园林应用提供依据。     

城市秋色叶树种资源应用探讨

秋色叶树种在我国园林造景中具有举足轻重的作用。为了合理开发和利用秋色叶树种资源,笔者总结了目前在我国园林中广泛应用的秋色叶树种资源,分析了它们在城市园林中的应用情况及应用方式,并指出了一些今后可供利用的秋色叶树种资源。     

湖南仙庾岭风景名胜区秋色叶植物群落研究

指出了湖南仙庾岭风景名胜区属于中亚热带丘陵地区,地带性典型植物群落为常绿阔叶林。对景区总体植物群落类型及其结构、种类组成进行了调查研究,结果表明:秋色叶植物群落可以划分为5类:香樟·枫香群落、枫香群落、檫木群落、白栎群落、山乌桕群落,通过分析各典型群落的种类组成、结构特征及景观特征,为选择和合理运用秋色叶树种资源、山林植物景观修复提供依据,有助于该区系中亚热带含有常绿成分的落叶林植被的演替研究。     

秋色叶树种的造景手法及园林应用

秋色叶树种是表现秋季景观的重要造景材料.从造景的角度,初步探讨了秋色叶树种在园林中的应用.     

秋色叶树种特性及其园林造景应用

秋色叶树种进入秋季后,其叶片的色泽较为均匀地由绿色转为其它颜色,具有较强的观赏价值。应用这一特性,在园林景观建设中点缀种植,可提供良好的视觉效果。文章介绍了常见秋色叶树种的品种、色泽、地域及其在园林景观中的栽植方式及应用。     

呼和浩特市秋色叶树种资源及其在园林中的应用

文章分析了呼和浩特市地区秋色叶树种的资源、类型,主要树种的性状、特征、观赏价值及其在园林绿化中的应用方式,初步探讨了秋色叶植物的造景形式,提出了合理开发和利用秋色叶植物的建议。     

庐山自然保护区秋色叶树种观赏特性及其园林造景应用

介绍庐山保护区秋色叶树种观赏特性,从造景的角度,探讨秋色叶树种在园林中的应用,并提出开发对策。     

浅议华北地区秋色叶树种的应用——以太原市和石家庄市为例

对华北地区秋色叶树种资源进行了调查,分析了秋色叶树种在园林造景中的美学价值、使用价值和文化价值。筛选出了适宜华北地区栽植的秋色叶树种,介绍了树种间的配置原则及配置形式,为华北地区的园林绿化提供了理论依据。     

Planning tree species diversification in Kenya based on differences in tree species composition between farms. I. Analysis of tree uses

Concerns exist about the limited diversity of tree species in agricultural landscapes. Complete tree inventories were carried out on 201 farms from four villages in western Kenya to establish whether significant differences in tree species composition existed between farms, and if so their magnitude and implications for new introductions and plantings. Tree species composition was interpreted to encompass elements of both tree identity and abundance. Tree identity was viewed from both taxonomic and function (e.g. fruit, timber, medicine) perspectives. Novel types of ordination using the Hellinger ecological distance and polynomial Redundancy Analysis indicated wide heterogeneity between farms with respect to tree species composition. For the 12 most prevalent functions of trees, the analyses showed significant differences (p<0.05). Partitioning of variance identified that village location explained much of the differences between farms suggesting that farmers share tree species within villages more than between villages. Differences between farms were assessed on two-dimensional ordination graphs. For five important tree functions, including beverage, charcoal, construction, fodder and medicine, two species dominated the compositional differences. For these functions, diversification can be achieved by village-to-village sharing even in the absence of any new species introductions. A general process to determine the degree of tree diversity at farm and landscape levels and steps to increase it are discussed.     

雪灾对南京林业大学树木园内5树种破坏情况的调查

针对雪灾对南京林业大学树木园内5树种的影响,分析其造成破坏的主要原因,并从树木选择、管理、种植等方面探讨了减灾防灾的策略。     

Planning tree species diversification in Kenya based on differences in tree species composition between farms. II. Analysis of tree niches.

Concerns exist about the limited diversity of tree species in agricultural landscapes. Complete tree inventories were carried out on 201 farms from four villages in western Kenya to establish whether significant differences in tree species composition existed between farms, and if so their magnitude and implications for new introductions and plantings. Novel types of ordination using the Hellinger ecological distance and polynomial Redundancy Analysis indicated wide heterogeneity between farms with respect to tree species composition of five niches, including homestead, cropland, fallow, woodlot, and external boundary (p ≤ 0.05). Multiple regression analysis confirmed the ordination results using the abundance of dominant species as the response variable. The relationship between location and species composition differed with those of two previous surveys. Methodological differences in sampling intensity, locations and time of sampling between these surveys could have caused the difference. The maps of spatial distribution of compositional types provided in the previous surveys were not confirmed, whereas villages were found to contain several farms with a species composition that was not typical of their village. Meaningful results about the species composition of a landscape should include several farms per village and use a sampling grid finer than 5×5 km².     

扬州古运河风光带绿地树种配置分析

扬州古运河城区段大水湾-便益门桥的绿地树种调查表明,共88种,分属43科67属.乡土树种与外来树种比为1.44：1,常绿树种与落叶树种比为0.63：1,乔木与灌木比为1.5：1;观花树种42种,花期主要分布在3～7月.对绿地模式的功能定位、模式结构、树种配置等作了论述,并对进一步的绿地树种规划和完善提出对策和建议,有利于绿地生态效益、环保功能及保健功能的实现.     

Fire resistance of tree species explains historical gallery forest community composition

Fire, climatic variability, and grazing by large herbivores have historically limited woody vegetation in the tallgrass prairie region of North America to gallery forests in protected areas along rivers and streams. Fire, in particular, has been a strong selective pressure against woody vegetation. Consequently, we expect that dominant tree species in these forests have developed mechanisms for tolerating periodic surface fires. Susceptibility of trees to fire damage depends in part on key properties of bark which influence heat transfer to the vascular cambium, including thickness, density, and moisture content. An historical (1983) survey of Konza Prairie Biological Station in northeast Kansas, USA indicated that gallery forests were co-dominated by Quercus macrocarpa and Quercus muehlenbergii, while Celtis occidentalis occurred as an important sub-dominant species. Populus deltoides, Gleditsia triacanthos, and Juniperus virginiana were relatively uncommon. To test the hypothesis that historically dominant gallery forest tree species are more resistant to fire damage than uncommon species, fire was applied to the bark of 10 individuals of each of these six species under conditions mimicking surface fires (400 °C for 120 s). Maximum temperature at the vascular cambium, bark thickness, bark moisture content, and bark density were measured. Trees were considered fire-resistant if the vascular cambium temperature remained below the thermal cell death threshold, 60 °C, throughout the treatment. Using logistic regression, bark thickness was found to be a significant predictor of lethal cambium temperatures (P = 0.002), while neither bark density nor moisture content were significantly related to lethal cambium temperature (P = 0.279 and P = 0.131, respectively). Across species, a minimum bark thickness of approximately 8.6 mm was necessary to maintain the vascular cambium temperature below 60 °C. Trees that produce thick bark quickly in juvenile size classes (P. deltoides, Q. macrocarpa, and Q. muehlenbergii) experienced lower temperatures at the vascular cambium than those which do not develop thick bark with increasing diameter (C. occidentalis, G. triacanthos, and J. virginiana). Ranking these tree species by either the DBH or age needed to develop the minimum protective bark thickness largely agreed with ranking based on historical relative importance. As fire frequency and intensity decrease in remnant tallgrass prairie of North America as a result of habitat fragmentation, fire suppression, and changing land management, fire-sensitive species may increase in relative importance in gallery forests because of increased juvenile survival.     

Lithuanian forests and climate change: possible effects on tree species composition

Outputs from the HadCM3 Global Climate Circulation Model according to scenarios A2 and B1 were used for climate change predictions in Lithuania. According to scenario A2, the annual temperature will increase by approximately 4.0 °C from 2061 to 2090, while scenario B1 predicts an increase of 2.0 °C. In contrast to scenario B1, scenario A2 predicts an annual increase in precipitation of 15–20 % at the end of the century. Based on the predicted climatic data for the two scenarios and climate maps by European Food Safety Authority for the EU, we created climate analogues for Lithuania for 2031–2060 and 2061–2090. These areas were overlain by the digital map of native tree species distributions in Europe, which was created from the European Forest Genetic Resources Programme database. If climate changes occur according to scenario B1, in 2031–2060, Lithuania’s climate will become suitable for approximately five to six alien species, such as Acer campestre, Acer pseudoplatanus, Fagus sylvatica, Populus nigra, and Prunus avium. In 2061–2090, these species will be joined by Sorbus domestica and Tilia platyphyllos. If climate changes occur according to scenario A2, at the end of the twenty-first century, Castanea sativa, Quercus pubescens, and Sorbus torminalis could expand this list. With respect to species dispersal rates, there is a high probability that the species A. campestre, A. pseudoplatanus, P. nigra, and P. avium will become immigrants to Lithuanian forests at the end of the twenty-first century. Approximately 20 new species native to Europe will be suitable for cultivation (scenario A2). Climate change will affect the distributions of native species too. An increase in the proportion of deciduous tree species (except Alnus incana) and some reduction in the proportion of conifers, Norway spruce (Picea abies) and Scots pine (Pinus sylvestris), are expected in Lithuanian forests.     

苏州主要园林树种的光合固碳能力对比分析

园林树种的光合固碳能够维持城市空气中CO2和O2的平衡。以苏州地区32个园林树种为材料,利用Li-6400便携式光合作用仪测定了其光合日变化,并利用测定结果计算其日净固碳能力,再以聚类分析法对其日净固碳量进行分类。结果如下:第1类[日净固碳量极高,17.55~18.76 g/(m2·d)]有紫荆、枫杨、垂柳,第2类[日净固碳量高,12.25~16.02 g/(m2·d)]有大叶女贞、乌桕、榉树、枫香树、垂丝海棠、樱花、夹竹桃,第3类[日净固碳量中等,8.57~11.97 g/(m2·d)]有银杏、红花檵木、朴树、乐昌含笑、红叶李、杜英、海桐、金边黄杨、杜鹃、重阳木、樟树、金丝桃、红叶石楠,第4类[日净固碳量低,3.81~7.64 g/(m2·d)]有红枫、洒金东瀛珊瑚、金叶女贞、八角金盘、五角枫、鹅掌楸、紫薇、木芙蓉、桂花。上述分析结果可对苏州的园林规划及树种选择提供一定的理论指导。     

武汉城区古树资源与树种规划

文章简要分析了武汉城区古树资源的特征,并从区分不同树种的使用目标、发挥生态功能、本地树种开发、园林群落多样性以及特色园林景观构建等5个方面阐述了古树资源对市区树种规划的意义。       

Exotic tree species displace indigenous ones on farms at intermediate altitudes around Mount Kenya

Agroforestry systems are potentially suitable for conservation of tree genetic resources. Farmers around Mt. Kenya usually integrate trees into their farm. Large parts of these trees seem to be of exotic origin, whereas indigenous species have priority for conservation. This study aimed at determining on-farm richness, composition and frequency of indigenous and exotic woody species around Mount Kenya to assess the suitability of farms for the conservation of indigenous tree species. 265 on-farm plots of 0.5 ha size each were selected in 18 different agro-ecological zones by using a stratified sampling scheme. All woody species within the plot were recorded with their local and scientific names. Total species richness was 424 (including 306 indigenous ones), mean richness per plot 16.5 species (including 8.8 indigenous ones). Eight out of the 10 most frequent species were exotic ones with Grevillea robusta from Australia ranking first (found on almost 76% of the surveyed farms). The proportion of indigenous species increased with increasing aridity and temperature. Dominance of exotic species was found at farms of humid mid- and highlands. Ordination analysis revealed that mostly exotic species contributed to separation of farms in the highlands and upper midlands, whereas indigenous species in the lower midlands and lowlands. As the frequencies of most indigenous trees were low, only parts of the surveyed farms can contribute to conservation of tree genetic resources, particularly the less intensively managed farms of the more arid lands. Farmers’ access to knowledge on valuable indigenous tree species and to quality seedlings of these trees need to be improved to increase indigenous species’ frequencies on farms and possibly to replace some of the exotic species in the future.     

长三角平原水网地区耐湿景观树种引种适应性评价与选择

根据多点造林3～4年的观测结果,通过生长、耐涝性、抗风性、抗病虫害和景观指数等指标,对从美国引进的20个耐水湿树种和种源进行综合评价。以耐涝、抗病虫和景观价值为主要评选目标。结果表明:以水紫树、黑栎、沼地紫树、苏玛栎、纳塔栎、落羽杉、美国枫香和美国梧桐的综合表现为优,北美鹅掌楸、复叶槭、河桦表现较差。引种试验结果为长江中下游平原地区生态和景观建设提供了优良的树种资源。