驻马店市乡土树种的园林绿化应用研究

通过对驻马店市乡土树种概况、乡土树种的优势及其意义的分析,针对驻马店市乡土树种在园林绿化应用中存在的问题,提出为何选择乡土树种、如何利用乡土树种,及对乡土树种的发展保护对策.     

乐昌林场造林树种选择浅论

对乐昌林场传统的造林针叶树种、经济林树种、引种树种和乐昌乡土树种进行分析评价。从"生态导向,保护优先"的森林经营方针选择造林树种,将乐昌乡土树种分为7个类型。     

河北省城市园林绿化树种应用现状与分析

以河北省2007-2008年主要城市园林绿化植物应用普查为契机,对11个设市城市园林绿化树种应用现状进行统计分析和研究,包括树种种类组成、主要树种比例、树种生长适应性等现状,指出目前河北省城市园林树种应用存在以下问题:树种种类不够丰富；乔、灌比例失调；树种应用频度较低；乡土树种应用比例不高；树木养护管理有待加强等.针对...     

阜新市区园林树种组成结构调查与分析

通过对阜新市区内各类型绿地中典型绿地的实地调查,从乡土树种与外来树种,常绿树种与落叶树种,乔木、灌木与藤本,速生树种与慢生树种,以及树种的观赏特性方面分析了园林树种的组成结构,并在此基础上提出了适宜的比例关系与改进方法。     

如东沿海林木乡土树种选育技术研究

通过对如东沿海林木乡土树种选育技术及引进外来树种培育利用研究，结果表明：榆树、桑树、苦楝、臭椿、乌桕、榉树、水杉、刺槐、银杏、55杨等树种是最适合如东沿海地区生长的乡土树种，可以大面积推广。实践证明：乡土树种优势明显、有较强的适应性、抗逆性和抗病虫害能力，这些树种生长健壮，冠大荫浓、抗寒、抗旱、抗污染、耐瘠薄土壤、适应性强、能发挥最大的生态效益。通过对现有乡土树种的筛选培育和引进新的树种进行驯化培育，不断丰富了如东沿海地区的树种资源，对如东沿海防护林标准和功能的不断完善提高、保持生态平衡、改善人居环境等方面都具有一定的积极作用。     

大同市园林绿化植物调查浅谈

为了建设生态型园林城市,最大限度地发挥本地树种优势,非常有必要对本地园林绿化树种的生长表现进行全面系统的调查,掌握其实际生长情况。对树种的园林应用情况、栽培和生长情况、树种在本地的物候期、树种的生长发育情况、树种的景观效果等方面进行系统全面的调查。     

益阳市主城区园林树种规划

在对益阳市主城区常见园林树种的应用现状调查基础上,分析了其树种规划中存在的问题,探讨了树种规划的基本原则,并在该原则的指导下,对益阳主城区的基调树种、骨干树种、一般树种进行了规划。     

蒙自市园林绿化树种的调查与评估

阐述蒙自市园林绿化树种的调查结果,从树种的生物学特性、生长状况、园林观赏效果、抗性等方面进行分析和论证。在此基础上对蒙自市现有的园林绿化树种进行评估和分级,总结蒙自市园林绿化树种的特点和不足之处,并为今后园林绿化树种的规划与选择提出合理建议。     

寒地城市园林选择树种的适应性分析

寒地城市因其寒冷的气温条件,对树种的选择较为苛刻,不加分析的选择树种,会导致树种选择的失败。寒地园林树种的选择需以寒地城市边缘树种以及其耐寒性为基础,综合利用寒地城市的气温数据对不同树种的影响进行选择。现以黑龙江省为例,根据黑龙江省主要城市的气温数据,从18种黑龙江边缘树种中选择出适宜应用于黑龙江园林的4种树种,对其进行试验论证。结果表明:山杏、金叶榆和四翅滨藜具有良好的寒地适应性,山樱桃的寒地适应性较弱。     

苏州市姑苏区常见乡土树种的初步调查与分析

本文运用园林花卉学、园林树木学、生态学等相关理论、方法以及前人的相关研究成果,通过对苏州地区天然次生林群落的树种组成、四旁绿化树种和城市绿化树种调查研究乡土树种在城市景观绿化中的应用情况的表述以引起相关从业人员对乡土树种的重视。     

Spread of mistletoes (Amyema preissii) in fragmented Australian woodlands: a simulation study

A simulation model was used to study the interaction between landscape pattern and components of the dispersal strategy of the mistletoe Amyema preissii by mistletoe birds (Dicaeum hirundinaceum). The landscape was modelled as a map of host trees for the mistletoes, characterised by the total density and clumpiness of trees. A landscape was considered as a set of equal sized bird territories, with the majority of seeds produced in such a territory dispersed within that area. Age-specific birth and death rates of mistletoes were measured in the field. Seed dispersal was characterised by four parameters: the fraction of within-tree seed dispersal, the ratio of attractiveness to birds of tree canopy volume over attractiveness of mistletoe fruit number, seed survival, and the fraction of seeds leaving their original territory.A sensitivity analysis was carried out using a factorial design on landscape type and dispersal parameters. General linear modelling of mistletoe population size after 100 years showed that, in a given landscape, seed survival was the strongest determinant. Total mistletoe population also increased exponentially with tree density, but the number of mistletoes per tree decreased. Population size depended on tree clumping as well, with larger mistletoe populations sustained by woodlands with clumped trees.For a given level of seed survival, population size increased when birds were more attracted by canopy volume than by fruit crop. The strongest increase in population size occured for a combination of low tree density with high relative attractiveness. The relative effects of the fraction of within-tree dispersal and tree density depended on seed survival. For lower survival, fraction of within- tree dispersal determined population size more strongly while for higher survival, tree density became the dominant factor. Population size was negatively correlated with the fraction of within-tree dispersal. Finally, population size strongly increased only if dispersal out of a bird's territory represented 10% of the seed crop, a high value which seems unlikely in the field.The results support the hypothesis that woodland fragmentation promotes invasion by mistletoes. Although simulated mistletoe populations deviated from our natural population in having an excess of young individuals, sensitivity analysis produced several non- intuitive results and is thus valuable in focussing further efforts on field data collection. This study also illustrates how a simulation model of population dynamics can help in determining control strategies for an invasive organism. A reduction in seed survival and disinfection of larger trees would appear to be the most efficient strategy.     

An analysis of structure of tree seedling populations on a Lahar

The structure of a tree seedling population is dependent on the interaction of several processes including seed dispersal, germination, survival, and competition on a physical landscape. Structural components (composition, size distributions, spatial distributions, age distributions, density, and history) of a tree seedling population on the Muddy River Lahar on the east side of Mount St. Helens were examined over a range of extents (1/10 m to 1000 m). Many of these component have rarely been examined at the larger extents listed here. Composition reflected distances to seed source and seed morphology. Seedling sizes are inversely proportional to depth to a buried soil if one existed. Spatial patterns indicated that seedling are clustered for tree seedlings less than 200 m apart, random for tree seedling from 200 m to 400 m and uniform for seedling greater than 400 m apart. This was confirmed by two measures of multidimensional spatial point pattern. Age distributions did not reflect the size distributions; old seedlings could be almost any size, young seedlings were constrained to be small in size. Densities appear to be typical for forests in the area. History of disturbance events (the lahar establishment, and successive ash, pumice, and erosion) has strongly influenced this tree seedling community.     

提高桂花种子发芽率的研究

采取多种措施处理桂花种子,提高桂花种子发芽率.结果表明:4月中下旬收种(树上采摘)较为适宜;带皮桂花种子发芽率低,仅为9.0%;除去外果皮及果肉带壳桂花种子发芽率较高,达到43.7%,去壳后桂花种子发芽率为42.0%,GA3处理在10～100 mg/L浓度范围内浓度越高效果越好;经低温层积处理后播种的桂花种子,由于有腐烂现象,其发芽率偏低.     

香榧新品种‘玉山鱼榧’的选育

‘玉山鱼榧’是从磐安县野生榧树古树中选育出的新品种,母树为实生起源古树,通过无性繁殖培育子代。该品种种实、种核比当前香榧主栽品种‘细榧’大,种核表面有2~6只榧眼,成熟期较迟。种实长倒卵状椭圆形,假种皮维管束直或扭曲,平均单个鲜质量10.8 g,纵径3.74 cm,横径2.28 cm,种形指数1.65,假种皮厚0.35 cm,鲜出核率36.39%,干出核率67.15%;种核平均单个鲜质量3.9 g,纵径3.37 cm,横径1.49 cm,核形指数2.28,壳厚0.08 cm,干核出仁率66.55%;种仁平均单个干质量1.6 g,脂肪含量48.6%,总糖含量0.83%,蛋白质含量18.02%,品质佳,商品性能优良。在浙江磐安开花期4月中旬,成熟期第二年9月中旬,种实发育期17个月,树势强,结果早,丰产,稳产,经济寿命长。幼苗和幼树喜阴湿,怕高温干旱和强日照,开始结实后又需要有充足的阳光,根系耐湿性差,怕积水。采用SSR分子标记对‘玉山鱼榧’的遗传鉴定表明,‘玉山鱼榧’与‘细榧’在DNA水平上存在明显的差别。‘玉山鱼榧’适宜在浙江省香榧产区栽培,其栽培技术要求与‘细榧’相同。     

柳州植物景观特色分析

介绍了柳州园林植物资源,并对树种选择和植物配置进行探讨,总结出柳州的植物景观特色,并评价选择和配置的优点和缺点,最后提出改进的对策和建议.     

Culture of triploid tissue from the endosperm of an endangered Chilean tree species Gomortega keule

The endangered Chilean tree species Gomortega keule (Mol.) Baillon produces an edible fruit, but is not cultivated at present. Recent advances in micropropagation may allow the further development of this species as a fruit crop. Triploid plants have been regenerated from the endosperm of seed of a number of species. This is the first report on in vitro culture of the seed endosperm of G. keule in order to obtain triploid plants. Callus was formed from endosperm after 1.5 months on 1.0× Murashige and Skoog medium supplemented with 2,4-dichlorophenoxyacetic acid and 6-(γ,γ-dimethylallylamino) purine. Shoot primordia developed and produced shoots that could be cultured on Rugini medium containing 0.1 mg l^–1 α-naphthaleneacetic acid and 1 mg l^–1 6-benzyladenine. Shoot primordia cultured on Rugini medium containing 2 g l^–1 activated charcoal produced longer shoots and longer leaves compared to diploid genotypes. Flow cytometry and chromosome observations indicated that the callus tissue and plantlets derived from the seed endosperm were triploid. Endosperm culture represents a feasible method to regenerate triploid plantlets of this tree species within 18 months. Such material may be of value for the genetic improvement and future development of G. keule as a commercial fruit tree species.     

Roads limit of seed dispersal and seedling recruitment of Quercus chenii in an urban hillside forest

Paved roads in urban forests cause forest fragmentation and thus reduce animal populations, threaten dispersal and recruitment of animal-dispersed plants. Here, we tracked animal-mediated seed dispersal of Quercus chenii in the urban forest centre and near roadsides to test the effect of paved roads on seed dispersal and recruitment. We conducted experiments in a forest patch in urban areas of Wuhan, China. The forest was dominated by the focal tree species and separated by paved roads. Only two potential seed dispersal animals, one rodent (Niviventer confucianus) and one jay (Garrulus glandarius) were observed in this stand. Seeds were removed farther but not as fast in the forest centre compared to roadsides, while no differences of seed fate, dispersal direction, and seedling establishment were detected between the forest centre and roadsides, indicating the thick vegetation along roadsides provided feeding shelters for small animals. However, when compared with primary forests containing more seed dispersers, seed removal rate in this urban forest fragment was much slower in both forest centre and roadside. Furthermore, due to road barriers, seeds were seldom moved across the paved road and remained in the fragmented stand, reflecting a limited function of seed dispersers. These results suggested paved roads isolated forests into small “islands” and weakened the ecological function of seed dispersers by impeding long distance seed dispersal. Reintroducing dispersers and building wildlife corridors would be impactful ways to restore urban forest patches.     

Climatic, landform, microtopographic, and overstory canopy controls of tree invasion in a subalpine meadow landscape, Oregon Cascades, USA

Tree invasions have been documented throughout Northern Hemisphere high elevation meadows, as well as globally in many grass and forb-dominated ecosystems. Tree invasions are often associated with large-scale changes in climate or disturbance regimes, but are fundamentally driven by regeneration processes influenced by interactions between climatic, topographic, and biotic factors at multiple spatial scales. The purpose of this research was to quantify spatiotemporal patterns of meadow invasion; and how climate, larger landforms, topography, and overstory trees have interactively influenced tree invasion. We combined airborne Light Detection and Ranging (LiDAR) characterizations of landforms, topography, and overstory vegetation with historical climate, field measurements of snow depth, tree abundance, and tree ages to reconstruct spatial and temporal patterns of tree invasion over five decades in a subalpine meadow complex in the Oregon Cascade Range, USA. Proportion of meadow occupied by trees increased from 8?% in 1950 to 35?% in 2007. Larger landforms, topography, and tree canopies interactively mediated regional climatic controls of tree invasion by modifying depth and persistence of snow pack, while tree canopies also influenced seed source availability. Landscape context played an important role mediating snow depth and tree invasion; on glacial landforms tree invasion was negatively associated with spring snowfall, but on debris flows tree invasion was not associated with snow fall. The importance of snow, uncertain climate change impacts on snow, and mediation of snow by interacting and context dependent factors in complex mountain terrain poses substantial hurdles for understanding how these ecotones may respond to future climate conditions.     

The re-emergence of indigenous forest in an urban environment, Christchurch, New Zealand

Christchurch, the second largest city in New Zealand is a planned city on a coastal plain on the east coast of the South Island. The birth of the city and the subsequent century of development was characterised by colonial values and tree and garden planting with familiar European species along with those from Australia, North America, and eventually all other continents. The image of an “English garden city” with classical parks of oaks and willow-lined rivers became the accepted norm and the way in which the city has been promoted to potential tourists. Gardening is one of the top two recreational activities and exotic species greatly outnumber native species in the flora and in gardens. This has had serious consequences for the highly fragmented and degraded indigenous vegetation and its co-adapted wildlife. A few hardy indigenous species continued to regenerate through this period, but since the 1970s, there has been a progressive change of attitude and interest in reclaiming the natural heritage of the city, manifest in widespread private and public planting of indigenous species and active habitat restoration. In this article we examine the indigenous and exotic shrub and tree components of the Christchurch flora as planted street trees, in domestic gardens, and in parks. We also present data on shrub and tree regeneration in parks and domestic gardens in the city. Indications are that the more sensitive, less intrusive management of urban environments, combined with the greater density of indigenous seed sources, has allowed regeneration of a wide range of indigenous species across a broad spectrum of habitats – from neglected gardens to pavement cracks to exotic plantations. This is despite the competition from the prodigious seed banks and density of exotic trees, shrubs, and ground covers and albeit minimal impacts of introduced browsing and seed eating mammals. If the present trends continue through appropriate management and facilitation, these tentative signs of native forest regeneration should eventually proliferate into a sustainable mixed origin urban forest that resurrects and preserves the natural character of the region.     

Fire severity and seed source influence lodgepole pine (<Emphasis Type="Italic">Pinus contorta</Emphasis> var. <Emphasis Type="Italic">murrayana</Emphasis>) regeneration in the southern cascades,Lassen volcanic National Park,California

Rocky Mountain lodgepole pine, (Pinus contorta var. latifolia) regenerates quickly after high severity fire because seeds from serotinous cones are released immediately post-fire. Sierra lodgepole pine (P. contorta var. murrayana) forests burn with variable intensity resulting in different levels of severity and because this variety of lodgepole pine does not have serotinous cones, little is known about what factors influence post-fire regeneration. This study quantifies tree regeneration in a low, moderate, and high severity burn patch in a Sierra lodgepole forest 24 years after fire. Regeneration was measured in ten plots in each severity type. In each plot, we quantified pre- and post-fire forest structure (basal area, density), counted and aged tree seedlings and saplings of all species, and measured distance to the nearest seed bearing tree. There was no difference in the density of seedlings and saplings among severity classes. Distance and direction to the nearest seed bearing lodgepole pine were the best predictors of lodgepole seedling and sapling density in high severity plots. In contrast to Rocky Mountain lodgepole pine, regeneration of Sierra lodgepole pine appears to rely on in-seeding from surviving trees in low or moderate severity burn patches or live trees next to high severity burn patches. Our data demonstrate that Sierra lodgepole pine follows stand development pathways hypothesized for non-serotinous stands of Rocky Mountain lodgepole pine.