The role of greening in environmental prevention and control

As an indispensable part of modern city, the greening construction of cemetery represents and affects the greening style and level of the city to a certain extent. Most cemeteries are built on barren hills and wasteland in the suburbs, so it is of great benefit to actively explore and study the ecological greening model of cemeteries in mountainous cities.

Mountain area is not only the concentration of natural resources, cultural diversity and biodiversity, but also the ecological barrier of plain area. As the center of funeral culture, the planning and construction of mountain city cemetery affects the process of social funeral culture to some extent. Due to the particularity and complexity of mountain ecological environment, the construction of cemetery in mountain cities faces many complicated problems. Due to the lack of systematic theoretical guidance, blindly following the planning theory and method, structural layout mode and technical index system of flat land, soil erosion and natural resource consumption are serious, the ecological environment is destroyed, the mountain habitat is further deteriorated, and the distinctive personality and local characteristics of urban cemeteries gradually disappear.

The main reasons for this situation are the neglect of greening construction, the neglect of natural ecological characteristics in mountainous areas in planning, and the blind follow of plain greening model, which can not form an effective mountain greening system, resulting in chaotic environmental structure and unbalanced ecological environment. Therefore, it is an urgent task to establish an internal order that adapts to the mountain ecological environment and reflects the spatial pattern of cemeteries in mountain cities.

1 Establishment of Ecological Greening Model of Shancheng Cemetery

Due to the complex terrain of urban cemeteries in mountainous areas, natural elements such as mountains, gullies and streams often cut, insert or even pass through urban cemeteries, which makes the cemetery land scattered and forms many irregular blocks, belts and wedge-shaped areas. The "ring+wedge" greening model of planar cemeteries (Figure 1) is difficult to apply.

Through the analysis of natural ecology and human ecology in mountainous areas, combined with systematic engineering methods, an ecological greening model can be established to adapt to the spatial structure of mountain cemeteries, that is, the network ecological greening model of "green block+green corridor" (Figure 2). Formally, it presents an irregular and open network greening structure, which is formed by connecting corridor green space (green corridor) and block green space (green block).

The so-called "green block" refers to the small ecological units in urban cemeteries. They are the basic perceptual elements that constitute the natural ecosystem of mountain cemeteries, which have relatively independent natural ecological characteristics and can form a microclimate environment. They are all over the cemetery area, with strong accessibility and are most easily experienced by people. In natural form, it is mainly manifested in landscapes, such as primitive vegetation on hills, valleys, steep slopes, ridges and gullies, as well as natural greening near rivers, rocks and beaches; In the artificial form, there are mainly public green spaces, green belts and gardens. The so-called "green corridor" refers to the green belts along natural rivers, valleys, ridges or valleys, water bodies, three-dimensional green belts unique to mountain cliffs, stepped green belts, green belts in funeral functional areas (such as burial areas) and so on. In this way, through the green corridor, a series of green blocks such as public green space, gardens and scenic spots are connected to form an overall greening network.

From the natural ecology of mountain city cemetery, this green space system combining point, line and surface conforms to the theory of landscape ecology in landscape structure; Urban cemetery is a landscape unit composed of matrix, corridor, block and other structural elements, in which all components are interrelated and interacted through certain flows (people or things), such as one-way flow of people in the cemetery and selective flow of people coming and going. ), form a specific distribution and combination form in space, and complete the ecological function undertaken by the urban cemetery system.

In the "green block+green corridor" network ecological greening model, the main parts of urban cemetery landscape-funeral buildings, funeral function subjects (such as tombstones) and road system can be regarded as the matrix of urban cemetery landscape, while the green blocks with obviously different appearance and texture can be regarded as inlays and the green corridors can be regarded as corridors. In this way, the green space system planning of mountain cemetery is to form a perfect mountain cemetery ecosystem by improving the quality and connectivity of green blocks, strengthening the construction of green corridors, and rationally adjusting the spatial layout of green blocks, green corridors and substrates.

2 "Green block+green corridor" network characteristics of the ecological greening system

From the natural, social and economic perspectives of cemetery ecology in mountainous cities, the "green block+green corridor" network ecological greening system has the following characteristics and advantages:

2. 1 adaptability

Due to the division and restriction of the natural landscape of mountainous cities on the cemetery space, the development and development of urban cemeteries presents a group or strip shape. The network ecological greening mode of "green block+green corridor" has strong adaptability. It conforms to the terrain and follows the slope, integrates the relatively scattered urban cemetery space, greatly improves the urban cemetery space, and makes the greening system truly become an organic part of the mountain city cemetery.

In this model, the advantages and disadvantages that have a significant impact on the ecological environment of the cemetery are analyzed by applying modern ecological principles, and the corresponding block green spaces (scenic forests, small gardens, etc.) are also analyzed. ) to inhibit or counteract harmful factors. These highly targeted massive ecological green spaces are based on the artistic configuration of ecological communities and aesthetics. This greening mode organically connects the green space inside the urban cemetery with the external natural environment with the help of the green corridor, forming the mutual borrowing of garden landscapes and maintaining the continuity of natural communities, and realizing the * * * life and * * * happiness between man and nature.

2.2 Permeability

Ecosystem is a combination of natural part and artificial part, and they are closely related. Different factors have certain influence on the habitat of biological communities. The special climate and site conditions create a new habitat for plant growth that is different from the natural state. On the basis of the ecosystem structure of the cemetery, structural replication and functional simulation of ecological engineering can be carried out to optimize the ecological structure of the cemetery and make it a whole. In the planning of land and space utilization, plants, buildings, water bodies and other material elements are used, and under the guidance of certain scientific, technical and artistic laws, plants are selected and configured according to the place and time to give full play to their comprehensive functions.

Based on the inherent mechanism of mountain natural ecology, the "green block+green corridor" network ecological greening model permeates every corner of urban cemeteries with strong penetration and vitality. For example, in the mountain city cemetery, there are some uncultivated land with dramatic terrain changes. The roads in mountain cemeteries are mostly built by splitting mountains, leaning against mountains and facing cliffs. In these areas, reasonable arrangement of climbing, vertical and ground cover plants for three-dimensional greening can easily form a stable multi-layer mixed three-dimensional plant community with trees, shrubs and the lowest ground cover plants, which not only enriches the landscape level, improves the greening rate and green visibility, but also makes plants compete with each other and be full of vitality.

2.3 Systematization

The particularity of natural ecological environment in mountainous areas often leads to the fragmentation of cemetery space in mountainous cities, and this network-like overall greening model can strengthen the integrity and integrity of cemetery space in mountainous cities and promote the formation of an open spatial framework for its ecological structure. Due to the differences between natural mountains and rivers, it will show unique landscape characteristics and distinctive artistic personality, which can effectively alleviate the ubiquitous "cemetery characteristic crisis".

This greening mode structure is an open system, which has certain directionality and can be extended outward according to the terrain. It not only makes the greening system in a growing trend, but also guides the development of urban cemetery space and becomes a benign green ecological framework for the sustainable and coordinated development of cemetery space in mountain cities. It is not only conducive to the phased construction of cemetery in mountain cities, but also can form a combination of points, lines and areas by protecting key geographical elements, and control the ecological quality and changing trend of cemetery landscape in mountain cities from a long-term perspective.

2.4 Accessibility

With the acceleration of urbanization, it is fashionable to return to nature. People not only yearn to visit famous mountains and rivers, but also pay more attention to contact with nature in their daily lives. The reticular ecological greening system of "green block+green corridor" strengthens the closeness between special citizens (that is, people who go to funeral parlours) and green space, facilitates citizens' arrival, has high frequency of use and strong citizen participation, and truly plays the role of urban cemetery green space, so that people can have "the beauty of mountains and rivers, the love of nymphs" after funeral activities, and further strengthen the connection between people and nature, people and society.

2.5 culture

The setting of the greening system can be combined with the historical and cultural protection of the special section of the cemetery or the cultural and entertainment facilities of the cemetery, making it a cultural green network. Green space planning should make full use of the advantages of urban cemeteries. On the basis of excavating history and culture, combined with the setting of modern cultural facilities, we should grasp the cultural theme, spatial nature, artistic characteristics and people's feelings of each "green block", and establish a complete funeral activity network through connecting green corridors, so that mountain city cemeteries not only have funeral functions, but also become special places with cultural connotations for people to visit, appreciate and explore.

The theme of artistic conception we are pursuing is "harmony between man and environment", that is, garden ecological culture, so we should consider the cultural atmosphere of green space. In addition to the image of plants, squares, rest places, buildings, sculptures, cultural activities and other contents in green space should also be improved at the ideological and artistic level, which is an important combination of cemetery construction and spiritual civilization. For example, traditional sculptures can be set up in the cemetery green space, reflecting the thick burial and thin burial.

2.6 Economy

The ecological benefits of gardens are mainly realized by a certain number of green plants. The green area, green coverage rate and total leaf area should be considered comprehensively, and the plants with multi-layer structure should be configured according to the principle of combining plant ecology with landscaping. Through the combination of arbor, shrub and grass, the combination of sunny and shady, evergreen and deciduous, the scientific artificial community can be established, and the combined leaf area index can be improved, which can appropriately improve the planting density and upper and lower levels, and then gradually thinning. It not only ensures the scientificity of artificial communities, but also improves the economy of gardens. It can also maintain the stability of its landscape effect for a long time, and has strong ecology, preservation, appreciation and diversity. Make full use of plants to establish artificial communities, give consideration to both long-term and short-term effects when designing, appropriately select plants with high economic value such as medicinal plants, fruit trees and oil plants, and appropriately select large-scale seedlings to improve the economy of gardens.

The network ecological greening system of "green block+green corridor" can make use of any section of the cemetery in mountain cities, and even bring most of the unusable land with drastic terrain changes into the green space system for comprehensive consideration, so as not to occupy good land as much as possible, thus alleviating the contradiction of insufficient land for cemetery in mountain cities. At the same time, compared with the traditional large-scale green space, the belt-shaped and net-shaped green space increases the length of the edge of the green space under the same area, thus making more surrounding land appreciate (the memorial tombs sell well), which not only brings good social and environmental benefits, but also creates huge economic benefits.

3 "Green block+green corridor" network ecological greening case analysis

Shuangfengshan Cemetery is located in the western suburb of Shijiazhuang City, Hebei Province, which belongs to the alluvial area of large hills and is surrounded by natural and cultural landscapes.

3. 1 natural ecological environment and zoning characteristics of Shuangfeng Mountain

Shuangfeng Mountain shows the natural beauty of the internal environment by relying on the terrain, and its spatial character tends to be flat and broad, which is more approachable, realistic and humanized than Fengluanling Cave and Yayandong Mansion. A hollow and low strip is formed between the two mountains, which is characterized by low and quiet space and easy to render the atmosphere of the cemetery. Therefore, starting from the original terrain, we should change it to achieve a certain degree of twists and turns, and build a main road along the narrow strip to give full play to the charming function of winding and secluded, show the quiet and far-reaching natural features, and make pedestrians in a solemn atmosphere. Stepped pedestrian walkways were built from the square along the mountainside of the north wind, which created favorable conditions for "changing scenery". The valley extends eastward to the northeast depression and becomes an artificial lake. The lake is taken from the branch of the source canal and runs through the cemetery from the northwest corner along the north wall, showing the natural beauty of the water system. The internal environment of the cemetery also highlights the formal beauty of the plane layout and three-dimensional outline through the building (Figure 3).

3.2 The main "green blocks" in the greening system

3.2. 1 Mountain "green plot"

759 Pinus tabulaeformis in Beifeng constitute the landscape of "Songtao in Beifeng" scenic forest; 1 150 Platycladus orientalis of Nanfeng Mountain and "Nanfeng White Elephant" constitute the landscape of Fengjing Forest. These two garden landscapes constitute the main theme of the cemetery. You can see the pine and cypress in Beishan in most of the viewing spots in the park. When the snow presses the pine and cypress, it presents a magnificent winter landscape.

Robinia pseudoacacia is dominant in the west foot of North Fengshan, supplemented by walnuts and black dates. Every late spring and early summer, clusters of white Robinia pseudoacacia flowers are in full bloom, and the flowers are overflowing. Looking around, it looks like snow, forming the landscape of "Huailing Chun Xue" and becoming the transition between winter and summer. Apples and peach trees are planted in the valley between the two mountains, forming a continuous landscape of spring flowers and summer (autumn).

Platycladus orientalis is sparsely planted at the eastern foot of Nanfeng Mountain, with persimmon trees as the main scenery and Platycladus orientalis, Ginkgo biloba, Albizia Albizia and gold and silver trees as the background. In autumn, the landscape of "persimmon reflecting green" is formed, and all kinds of trees have different postures and irregular shapes. With the ups and downs of hills, the interest of Shan Ye is created, which not only makes autumn scenery stand out, but also makes the scenery transition in winter and summer.

3.2.2 Ashes Forest in Funeral Functional Area

Grey forest is dominated by evergreen trees such as pine and cypress, which are distributed in different areas of the cemetery according to the changes of topographic conditions and the needs of funeral and interment. This "green block" not only has the funeral function of burying ashes, but also has the landscape ecological function as a scenic forest.

3.2.3 Public Green Space

The public green space in commercial service area and living administrative area is mainly lawn, and it is planned and designed in the form of small garden to form a public green space with funeral home characteristics.

3.3 The main "green corridor" in the greening system

3.3. 1 Water System "Green Corridor"

The plant treatment of the whole water system is mainly to highlight the summer scenery, and pay attention to the transition treatment with the spring and autumn scenery. In the entrance treatment, the method of borrowing water is skillfully adopted, and the garden gate is built to be concave, so that the water system in the garden is exposed outside the gate. Through the treatment of water system, a small river is formed, and a bridge is built on the river, so that people can cross the bridge before entering the park and see the water before seeing the mountains. From the gate to the square, through plants and buildings, there is a transition from "barrier to semi-barrier and semi-exposure". As the starting scene of the cemetery, it closely follows the theme of "solemnity". In the square, you can see the central scenic spot of the cemetery-Beifeng Mountain complex through the trees, and you can also see the eastern tourist area through the trees, which not only increases the feeling of the environment, but also satisfies the psychology of stopping in the park and enriches the interest of the park. In the northeast of the cemetery, an artificial lake was excavated on the basis of the original low-lying terrain, and the revetment was built with bluestone. In the lake, Tingbu leads to the island in the middle of the lake, and weeping willows and peach trees are planted on the shore and island, which increases the interest of this scenic spot. The water in this lake is supplied by the branch canal of the source canal, and its entrance is located at the garden wall in the northwest of Beifeng Mountain. After treatment, it falls into the pool in the form of waterfall from the crevices, bypasses the northern part of Beifeng Mountain, breaks, continues, hides, shows, is urgent, slows down, gathers and disperses different water features through the twists and turns of the stream, and finally flows into the wide lake through Yuanmen Bridge. Flowers and shrubs such as weeping willows, peach trees and Xanthoceras sorbifolia are planted beside the stream, forming a moving scene of "peach blossoms full of fragrance".

3.3.2 Road "Green Corridor"

The main road in the park connects all functional areas and can also be a tour guide route. Platycladus orientalis is densely planted on both sides of the main road, which makes the road meander between slopes and detours in the dense forest, resulting in the artistic conception of "winding path leading to seclusion". The stairs leading from the square to the Beifeng Mountain complex are paved with cypress and crape myrtle, which is in harmony with the rhythm of the stairs. There is a word "wild" in the tour path, and rocks are scattered along the roadside, and flowering shrubs such as plum blossom and crape myrtle are planted. According to the principle of ecological greening, planting herbaceous flowers with strong self-sowing ability has increased the natural interest of the garden and enriched the landscape.

3.3.3 "Green Corridor" in Funeral Functional Area

In every area of the cemetery, juniper, boxwood ball, ginkgo, red plum, etc. are planted, and juniper is planted between tombstones; The buildings in the north and south Fengshan are dominated by thousands of cypresses, cedars and Pinus tabulaeformis, with a small number of flowering shrubs such as pearl plum, crape myrtle and clove. The dark green of pine and cypress is in sharp contrast with the gray and elegant colors of buildings, which makes the landscape look grand and solemn in color. The central axis road leading to the cemetery in Beifeng Mountain is closed with boxwood hedges on both sides, creating a sense of solemnity. Because there are many stones in the tomb area, it is not only in line with the ecological principle, but also in line with the requirements of bereavement and tourists to plant a variety of turf or vigorous grass roots in the gaps between red stone slabs or other hard materials (cement prefabricated products or stones with various patterns).

3.4 Analysis of the overall effect of mesh ecological greening

The planning of the green space system of Shuangfengshan cemetery is based on ecology, fully considering the characteristics of the natural environment in mountainous areas, and making use of the relationship with the surrounding environment to make the inside and outside echo and form an organic whole. By improving the quality and connectivity of green blocks, strengthening the construction of green corridors and rationally adjusting the spatial layout of green blocks, green corridors and substrates, a network ecological greening system with strong adaptability, permeability and systematicness has been formed (Figure 4).

In the process of ecological greening construction, plant allocation pays attention to the formation of multi-layer plant communities and gives full play to the role of plants in improving the ecological environment. On the premise of satisfying the ecological environment and landscaping, make full use of the original plants, combine them with fruit trees and medicinal plants, and combine the short-term and long-term effects to give full play to their social, environmental and economic benefits.

Because landscaping emphasizes the reappearance of natural beauty, cemetery greening has certain accessibility. By setting up sculptures and garden sketches reflecting funeral culture in the funeral function area, the cultural nature of the garden will be enhanced.

4 Conclusion and analysis

According to the complexity and particularity of the mountain ecological environment, through the full understanding and control of the unique landscape structural units, the network ecological greening system of "green blocks and green corridors" protects the fragile mountain environment, protects the diversity of vegetation and biology, and better maintains the ecological balance of the mountain environment.

The natural ecological environment in mountainous areas is extremely complex and has laws to follow. The planning of cemetery green space system in mountainous cities is directly related to the construction of ecological cemetery. Only by truly starting from the characteristics of natural ecological environment in mountainous areas and deeply digging and grasping its internal mechanism can we find the correct method of cemetery system planning in mountainous cities.

The proposal of "green block+green corridor" network ecological greening system is a useful discussion on the planning of cemetery green space system in mountain cities, but any greening model or system needs a lot of practice and theoretical deepening to adapt to the ever-changing mountain ecological environment. It is extremely important and urgent to establish a set of green space system planning methods and systems suitable for the natural ecological environment of mountain cemeteries, so as to better improve the environmental quality of mountain city cemeteries and promote the virtuous circle of cemetery ecology. Only in this way can the ideal goal of eco-city cemetery be realized, and the mountain city cemetery can embark on the road of coordinated, healthy and sustainable development.