The classification of ornamental trees is mainly to facilitate identification and application. There are many methods of classification. In addition to classifying ornamental trees according to the plant evolutionary system, they can also be classified according to other standards. For example: some are classified according to tree characteristics, others are classified according to ornamental characteristics, garden uses and application methods, and there are also comprehensive classification methods. From the perspective of application, the main classifications of ornamental trees are described as follows:

(1) Classification according to the characteristics of trees

Based on the characteristics of ornamental trees, it can be roughly divided into Divided into the following categories:

1. Coniferous trees

(1) Evergreen coniferous trees such as cedar, juniper, cryptomeria, podocarpus, etc.

(2) Deciduous coniferous trees such as golden pine, metasequoia, cypress, pond fir, larch, etc.

2. Broad-leaved trees

(1) Evergreen broad-leaved trees such as camphor, magnolia grandiflora, nanmu, sophora japonica, etc.

(2) Deciduous broad-leaved trees such as maple poplar, sycamore, zelkova, paulownia, locust tree, ginkgo, tomento poplar, etc.

In the tree category, according to the maximum height of the tree, it can be divided into large trees (up to 20 meters), medium trees (about 5 to 20 meters high), and small trees (height below 5 meters). .

3. Broad-leaved shrubs

Shrubs have no obvious trunk, or the trunk is very short, and the tree body has many side branches of similar growth. According to the growth habits of their leaves, they can be divided into:

(1) Evergreen broad-leaved shrubs such as gardenia, pittosporum, boxwood, boxwood, etc.

(2) Deciduous broad-leaved shrubs such as redbud, wintersweet, meadowfoam, eucalyptus, crabapple, plum, etc.

4. Vines

The stems are slender and cannot stand upright, and must extend forward by relying on other objects.

(1) Evergreen vines such as ivy, Trachelospermum, Fufangteng, etc.

(2) Deciduous vines such as Dijin, grape, Lingxiao, wisteria, etc.

5. Creeping species

The characters are like vines, but they cannot climb. They can only live on the ground, or lie on the ground first and then rise up, such as ground cypress, antler juniper, winter jasmine, etc. .

6. Bamboo

The characteristics and growth habits of bamboo are different from those of trees. There are many types and special functions. Such as Phoenix tail bamboo, filial piety bamboo, purple bamboo, Ruo bamboo, Buddha belly bamboo, moso bamboo, rigid bamboo, etc.

(2) Classification according to the ornamental characteristics of tree species

1. Flowers and trees

That is, ornamental trees. Those with distinctive features in flower shape, color, flower quantity, and fragrance are included in this category. Shrubs and small trees have a large proportion, have a long lifespan, can bloom every year, are rich in three-dimensional beauty, and are especially easy to cultivate and manage. Their main function in garden planting is to decorate and embellish the landscape. They can enrich the color of the garden and configure it into flower bushes, flower beds, flower borders and flower beds. Planting with a single type of flowers and trees can give full play to the individual beauty of the plants, or they can also form specialized gardens, such as peony gardens, rose gardens, plum gardens, begonia gardens, etc. There are also many kinds of flowers and trees used to decorate the flower border. There are many famous flowers and varieties, and the garden is filled with spring colors all year round, adding color to the garden.

Flowers and trees can be divided into spring flowers, summer flowers, autumn flowers and winter flowers according to their flowering period. For cross-season flowers and trees that have a special flowering period or can bloom multiple times under natural conditions, the former can also be classified into single-season flowers according to their initial flowering period and full flowering period, such as spring azalea, summer azalea, etc. The latter include Yueyuehong, crape myrtle, hibiscus, Milan, etc.

2. Leaf trees

That is, foliage trees. Mainly for ornamental leaf color and leaf shape, some can be viewed all year round. The colorful leaves are used to beautify the environment and decorate the hall. Management is easier than flowers and trees.

Leaf trees that mainly focus on color can be divided into two types: those with seasonal changes and those without seasonal changes according to their leaf color and its changing conditions. The former such as golden pine, mountain hemp, maple, pistachio, crape myrtle, euonymus, loblolly, nandina, polyphylla, heather, etc.; the latter such as purple-leaf plum, red maple, purple-leaf barberry, Poplar alba, poplar tomentosa, milkweed, Elaeagnus elegans, golden heart boxwood, golden peach leaf coral, red-backed osmanthus, variable leaf wood, etc.

3. Fruit trees

That is, fruit trees. Making use of the color, fragrance, shape and quantity of fruits for landscaping is a major feature of Chinese gardening. Fruit tree species used as ornamental trees are different from fruit trees. They are not intended to pursue their edible value, but they must be durable, not pollute the ground, and not attract insects and flies. This is its most basic condition, followed by the appearance requirements:

(1) Eye-catching colors such as Tianmu Qionghua, Purple Pearl, Hubei Begonia, Wolfberry, Big Fruit Holly, Hawthorn, Xiangyuan, Laoya Kaki et al.

(2) Strange shapes such as bergamot, grapefruit, hammer tree, prickly pear, pomegranate, papaya, etc.

(3) There are many species, such as pyracantha, viburnum, kumquat, nandina, grape, heather, loquat, etc.

4. Shade trees

That is, shade trees, including courtyard shade trees and street trees.

Those who choose courtyard shade trees must have dense crowns, tall trunks, fragrant flowers and fruits, large leaves with thick shade, smooth trunks without thorns, and can provide shade for people to rest under, such as Albizia julibrissin, Camptotheca acuminata, Liriodendron tulipifera, camphor, Maple poplar, beech tree, magnolia grandiflora, etc.; those selected as street trees must have straight trunks, graceful tree postures, no sprouting in the rhizosphere, strong adaptability, rapid growth, high branch points, and no obstruction to pedestrians and pedestrians. Vehicles can pass through it, and at the same time, it must have fast wound healing, be resistant to pruning, have strong germination ability, be resistant to smoke and dust, have few pests and diseases, have a wide source of seedlings, and have large seedlings that are easy to survive when transplanted and easy to manage, such as maple poplar, locust tree, two-ball sycamore, camptotheca, etc. Liriodendron tulipifera, tomentose poplar, thin-shell hickory, tangerine tree, metasequoia, etc. Street shade trees are related to urban beautification and environmental sanitation, so the identification of shade trees is the focus of landscaping.

5. Vines

Generally refers to woody vines, also known as vines. According to their main ornamental characteristics, they can be divided into three categories: leaf viewing, flower viewing, and fruit viewing. According to their growth habits and climbing methods, they can be divided into:

(1) Twisting type. The stems and vines spin left or right on the attachment. Such as wisteria, Akebia, honeysuckle, kiwi, etc.

(2) Climbing type relies on specific organs for climbing. According to their different climbing organs, they can be divided into:

Adsorption type: use aerial roots or suckers to climb. Such as Lingxiao, Luoshi, ivy, Fufangteng, Xili, Dijin, etc.

Hook attachment type: Use hook thorns for climbing. Such as Rubus, Yunshi, etc.

Tendril type: those who use tendrils to cling. Such as grapes, passion fruit, mountain grape, etc.

Stem-wrapped type: Climbing relies on the rotation reaction of the petiole. Like clematis.

The ones listed above can be directly climbed onto the wall or can be constructed using various supports to form a landscape, which is of great significance for making full use of land and space for vertical greening, increasing the greening area and beautifying the environment. This is particularly important for cities with densely populated areas and limited green land.

6. Forest trees

Generally refers to trees suitable for planting in patches in scenic areas and large landscaping areas to form the beauty of the forest. There are many species of forest trees with different morphological functions, but they require relatively developed trunks and crowns, and generally have strong adaptability or stress resistance. It is ideal to arrange sparse forests and groups of trees in the garden, or to use them as backgrounds or scenery barriers. It is especially indispensable when creating the natural scenery and quiet environment of mountains and forests. The world's four major park tree species - cedar, golden pine, golden pine and Araucaria all belong to this category.

Forest trees are divided into two categories: coniferous tree species and broad-leaved tree species according to their morphology and biological characteristics, each of which can be divided into evergreen and deciduous. Such as cedar, juniper, cryptomeria, whitebark pine, black pine, Huangshan pine, red pine, metasequoia, pond fir, water pine, golden pine, cypress, camphor, magnolia grandiflorum, woodland, beech, elm, poplar, oak. , Robinia pseudoacacia, etc.

7. Bamboo

Bamboos are a special group of higher plants. They are propagated by dividing underground stems (bamboo whips) and grow into new bamboos from bamboo shoots. They can grow into forests quickly. The bamboo forest has a long life after it is established, and the bamboo trees can be continuously adjusted for hundreds or even hundreds of years to ensure that Hsinchu is green and strong. The density, thickness, and height can be manually controlled during garden configuration. It is a commonly used tree species that embodies the characteristics of Chinese gardens. It is also an excellent material commonly used in modern gardens. When creating landscaping, methods such as solitary planting, cluster planting, opposite planting, and group planting are adopted. According to the growth conditions of underground stems and ground, there are the following three types:

(1) Single-axis scattered type such as moso bamboo, purple bamboo, mottled bamboo, square bamboo, Caolihuang, yellow-skinned bamboo, etc.

(2) Coaxial cluster type, such as Phoenix tail bamboo, filial piety bamboo, Buddha belly bamboo, etc.

(3) Double-axis mixed growth type such as tea stalk bamboo, Ruo bamboo, Feibai bamboo, etc.

8. Fences

Iron fences and wooden fences are common facilities around households, which have the function of isolation and prevention. Green hedges use green plants to form living, growing and pastoral hedges. In addition to its protective function, it can also be used to decorate the landscape, separate spaces, block sightlines, shelter shelters, or serve as basic planting for statues and sketches.

Hedges are not all green. Sometimes they can also be formed into flower hedges, fruit hedges, colorful leaf hedges, etc. The height of the hedge is usually about 1 meter, but the short one can be controlled below 0.3 meters, just like the edge of the garden; the tall one can be more than 4 meters, cut evenly, just like a majestic high green wall.

Hedges are usually densely planted in double rows and are pruned in strict accordance with the design intent. They can be made into various styles in order to be neat and beautiful, which is called whole-form hedges. However, for flower hedges, fruit hedges, thorn hedges, hedges, etc., in order to give full play to their main functions, there is generally no heavy pruning. Only individual branches should be treated, do not extend them too far, and pay attention to maintaining the necessary density, and then allow them to grow. Become a natural hedge.

As a hedge tree species, the best shapes are thin branches, small leaves, and evergreen. In terms of habits, they should also have the characteristics of "one slow and three strong", that is, dense branches and leaves and slow growth. , the lower branches are not easy to wither; the base has strong germination or regeneration ability; it can adapt to or resist adverse environments and has strong vitality; it is resistant to pruning and has strong branching ability.

The tree species suitable for arranging various hedges are described as follows:

Hedges: Ligustrum lucidum, small wax, big-leaved boxwood (trunk), boxwood, and Thousand-headed Cypress.

Colorful leaf hedges: golden-hearted boxwood, purple-leaf barberry, gold-sprinkled cypress, golden-leaf ligustrum, and red-flowered barberry.

Flower hedge: gardenia, camellia oleifera, rose, rhododendron, June snow, elm-leaf plum, hemp-leaf hydrangea, smile, eucalyptus, hibiscus, snow willow.

Fruit hedge: purple pearl, nandina, wolfberry, wolfberry, pyracantha, viburnum, and agarwood.

Prickly hedges: wolfberry (Citrus aurantium), oak, Zanthoxylum bungeanum, Caesculus caerulea, barberry, horsetail, juniper, alder and heather.

(3) Classification according to the practical value of trees

In addition to classification according to ornamental characteristics, ornamental trees can also be classified according to their practical value in landscaping, such as the location and protection of planting. functions are classified. According to the location of planting, it can be divided into street trees, shade trees, hidden trees, hedge trees, solitary trees and vertical greening tree species. The details are as follows:

1. Street trees

Street trees refer to the general term for trees planted on both sides of the road system. Including trees for road greening such as highways, railways, urban streets, garden roads, etc. The planting of street trees is of great significance in both urban and rural areas. The greening of road systems can not only make full use of land, develop production, and improve the environmental conditions of the road itself and its vicinity, but is also an important part of urban and rural gardens.

Urban street trees are an important part of urban garden construction, the skeleton of urban greening, and an element of urban environmental protection. Street trees can enliven the entire city, decorate the cityscape, reduce the scorching wind and dust on the streets, and reduce the noise of vehicles and pedestrians. Therefore, every city must pay attention to the planting of street trees and exert their due functional benefits.

In the countryside, roads extend in all directions and criss-cross. At the same time, there is sufficient sunshine on both sides of the road and the soil is relatively fertile, which is suitable for the growth of a variety of tree species, which can improve the ecological environment of the countryside.

Based on the road system and general functional requirements, the following principles should be followed when selecting street tree species:

Grow rapidly, have strong adaptability, have high branch points, and do not hinder vehicle traffic; It has strong budding ability, is resistant to pruning and shaping, and loses its leaves in winter (the southern climate is warm and the sunshine is strong, so evergreen tree species can be used); the crown is neat, the posture is graceful, the trunk is straight, and the rhizosphere does not breed new branches, which is convenient for shade; the life span is long, and it is resistant to smoke, dust, It has strong resistance to wind damage, pests and diseases, floods and droughts; the flowers and fruits are non-toxic, odorless, and do not pollute the environment or attract insects and flies; the sources of seedlings are abundant, and large seedlings are easy to survive when transplanted.

Commonly used tree species are:

Evergreen tree species: banyan, eucalyptus, camphor, magnolia, coral tree, casuarina, bayberry, etc. (mostly used in the south).

Deciduous tree species: sycamore, poplar, locust tree, chrysanthemum tree, neem tree, albizia julibrissin, triangle maple, compound leaf maple, tallow tree, camptotheca acuta, ginkgo, thin-shell pecan, eucalyptus, paulownia, maple Poplar, ash tree, tulip tree, horse chestnut, beech, metasequoia, ailanthus, pond fir, etc.

Monocotyledonous tree species: palm, coconut, palmetto, etc.

2. Shade trees

City streets, parks, and scenic spots have more tourists in summer and autumn than in winter. Therefore, in tourist areas and places with many pedestrians, how to survive the steaming heat and When the sun is in the sky, it is very important to have green trees for visitors to take shelter and cool down. Shade trees take advantage of the tall crowns and dense branches and leaves of trees to be planted in gardens, parks, squares, and boulevards to provide a canopy of green shade for people to rest and avoid the scorching sun.

Shade tree requirements: The crown is wide, the tree branches extend to all sides, and there are fewer lower branches; the leaves are large and dark green, and sunlight radiation is not easy to penetrate (deciduous trees are suitable in the north, and evergreen trees are suitable in the south). ); the trunk is straight, the branch points are high, and there are no thorns on the trunk, making it easier for people to move under the tree; it grows faster, has a longer lifespan, is not easy to age, and has strong resistance to diseases and insect pests; the flowers and fruits are luxuriant, the tree is tall and graceful, and it does not pollute the ground , can maintain environmental hygiene.

The planting locations of shade trees are mostly around buildings, on both sides of garden roads, on the southwest side of residences, as well as on lawns and open spaces in gardens. Commonly used shade tree species include:

Evergreen tree species: camphor, heather, eucalyptus, magnolia grandiflorum, ligustrum lucidum, holly, polyphylla, woodlotus, oak, oak, etc.

Deciduous tree species: Sophora japonica, Albizia julibrissin, beech, hackberry, five-cornered maple, ginkgo, double-yang tree, tallow tree, camphor tree, soapberry, pistachio, compound-leaf maple, neem, etc.

Vine plants for arranging green corridor scaffolding: wisteria, grape, woody vine, Dijin, Lingxiao, Trachelospermum, ivy, etc.

3. Hidden trees

We call trees that use their dense canopy branches and leaves to cover or divert certain buildings or simple viewpoints in the garden and increase the overall artistic effect of the garden. A hidden tree. In the garden, the following situations often need to be covered, such as simple parts of buildings, public toilets, walls with inconsistent colors, various blind corners, collapsed slopes and other buildings or facilities that have no ornamental significance and are unsightly. place.

To choose a concealed tree, you must have: lush branches and leaves all year round without falling leaves; a dense crown without gaps; strong resistance to adverse environments and pests and diseases.

Suitable trees for concealment include: Thousand-headed cypress, Platycladus arborvitae, juniper, privet, coral tree, hibiscus, mosquito tree, heather, holly, bayberry, boxwood, boxwood, and oleander. , purple bamboo, phoenix tail bamboo, plantain, palm, etc. Hidden trees are often densely planted to form green tree walls, which can play a concealing role in blocking sight.

4. Hedge species

Hedges are increasingly widely used in modern gardens, and their main functions are to separate protective areas and decorate the landscape.

Requirements for selecting hedge tree species: resistant to pruning and shaping, strong germination, clustered branches, dense foliage; tolerant to shade and cold, strong resistance to dust, bituminous coal pollution, and external mechanical damage; evergreen all year round, able to tolerate dense planting, and strong growth ability.

There are many types of hedges. In terms of form, there are two categories: natural and regular. In terms of ornamental properties, there are flower hedges, fruit hedges, thorn hedges, green hedges, etc.; in terms of height They are divided into high fences, medium fences and short fences (see the fence types mentioned above for details).

5. Solitary tree planting

In gardens, for the needs of shade or artistic composition, there are often two configurations of solitary tree planting: one is the solitary tree planting for shade, and the selected tree species The principle has been discussed in the section on shade trees. Another reason is the need for artistic composition. Solitary trees are often used as the main scene or focus of the local scene. Solitary trees should have: fast growth, strong adaptability, suitable for solitary planting; majestic body, graceful posture, beautiful branches and beautiful lines; luxuriant blooming , fruitful, or colorful, fragrant smell; seasonal changes, and strong contrast with the surrounding environment and other conditions.

The trees suitable for solitary planting include: whitebark pine, maple, maple, ginkgo, cherry blossom, locust tree, albizia julibrissin, crabapple, peach, plum blossom, cedar, podocarpus, horse chestnut, and tulip tree. , crape myrtle, white magnolia, magnolia grandiflora, purple leaf plum, tallow tree, heather, cryptomeria, etc.

6. Vertical greening tree species

The use of climbing plants to green buildings, fences, walls, garden gates, pavilions, corridors, scaffolding and other ancillary buildings is called vertical greening.

Vertical greening mostly uses the vine tree species mentioned above.

Although the artificial classification method of ornamental trees mentioned above is more practical, it is not very rigorous. Some tree species will have completely different tree bodies or leaves after changes in the ecological environment. There are reports of mutual transformation between trees and shrubs, and between evergreen and deciduous leaves. It is entirely possible for tree species to be classified according to their ornamental characteristics and functional uses to overlap. We can only give appropriate classification positions based on its main traits or functions.