The commonly used tree species in the north are the world's five largest park trees, garden shade trees, cedar, golden pine, Araucaria, giant sequoia, Japanese golden pine, the world's five largest street trees, horse chestnut, sycamore, ginkgo, tulip tree, and linden. The fir and silver fir, golden pine, Japanese golden pine, and Araucaria are collectively known as the world's five largest garden trees. The top ten street tree species in the north are the leucophylla, the locust tree, the French tung tree, the tomentary poplar, the evergreen ash, the horse chestnut, the sycamore, the ginkgo, the linden, and the goose tree. Urban greening cannot be separated from trees. Street trees are the basis of greening. The quality of tree species selection is directly related to the effect of urban greening. Based on my own work experience, the author gives a brief introduction to the types of street trees in the northern region. 1. Ginkgo: A large deciduous tree of the Ginkgo family, with a straight trunk, a broad and oval crown, and is dioecious. The leaves are fan-shaped and turn golden yellow in autumn. It is cold-resistant and light-loving, with deep roots and strong tillering ability. It likes to grow in sandy loam with a humid climate, deep fertile soil and good drainage. It is not suitable for planting in saline-alkali soil, heavy clay soil and low-lying land. It has strong drought resistance and long life. Propagate by sowing, cuttings, tillering and grafting. It is a large deciduous tree of the Metasequoia family. The crown is narrow and conical when young, and the branches expand into a broad oval shape when old. The leaves are linear, flat, and tender green. It is fast-growing, loves light, is cold-tolerant, and has strong adaptability. The groundwater level is too high, and its growth is extremely poor in low wetlands where water has been stagnant for a long time. It is resistant to salt and alkali (salt content below 0.2%) and has certain resistance to sulfur dioxide. Propagate by sowing seeds and cuttings. 2. Ligustrum lucidum: an evergreen tree of the Oleaceae family, with spreading branches, an obovate crown, leathery, opposite leaves, panicles, and small white flowers blooming in June, which are dense and fragrant. The drupe is oval, slightly curved, matures from November to December, and is dark purple-blue. It is a warm-land positive tree species that has been cultivated for a long time. It likes warm climates, is slightly shade-tolerant, and has strong adaptability. It grows quickly in moist and fertile slightly acidic soil, has a well-developed root system, strong tillering and sprouting ability, and is resistant to pruning and shaping. 3. Magnolia grandiflora: an evergreen tree of the Magnoliaceae family, with a broad conical crown, buds and branchlets rusty and pubescent, leaves obovate, oblong, leathery, with blunt leaf tips, glossy leaf surfaces, and rust and rust on the undersides of the leaves. Pluberous, thick petioles, cup-shaped flowers, white, fragrant, with purple filaments, aggregate fruit cylindrical oval, densely covered with rusty hairs, red seeds, flowering period from May to August, fruit ripening period in October. It likes sunshine, a warm and humid climate, and has certain cold tolerance. It is intolerant of dry and calcareous soil. It has strong resistance to various natural disasters. Its root system is deep and large, and it can also resist smoke and dust. Can be propagated by seeding. 4. Cedar: A large evergreen tree in the Pinaceae family, with a straight trunk, majestic and majestic, dioecious, with irregular whorled large branches and drooping twigs. It likes an environment with plenty of sunshine, humid and cool conditions, deep soil and good drainage. It can also grow in heavy loess and barren dry land. It can adapt to both acidic soil and slightly alkaline soil, but it will not grow well or even die in waterlogged depressions or places where the groundwater level is too high. Cedar has shallow roots and is prone to wind fall. Propagate by sowing, cuttings and grafting. 5. Whitebark pine: an evergreen tree of the Pinaceae family, with sparse and horizontal branches, an umbrella-shaped crown, green and tall. It likes light and cool, and grows well in deep, moist and fertile calcareous soil, loess and semi-shade conditions. It is also adaptable to slightly saline-alkali soil and calcareous soil. It can tolerate the severe cold of -30℃, but is afraid of heat and avoids moisture. Propagation by seeds. 5. Huashan pine: an evergreen tree of the Pinaceae family, with a broad conical crown, smooth and hairless branchlets, small winter buds, cylindrical shape, and chestnut brown. The leaves are in a bunch with 5 needles, soft in texture, and the cones are cone-shaped and long-ovate. When mature, the seed scales grow and the seeds fall off. The seeds are wingless or nearly wingless. The flowering period is from April to May, and the cones are from September to October of the following year. Ripe month. Yang tree likes a mild and humid climate, has strong cold tolerance, is intolerant to heat, and is intolerant to alkaline soil. It is propagated by sowing. 6. Black pine: an evergreen tree of the Pinaceae family, with orange-yellow branchlets and silvery-white winter buds. The branches spread horizontally and form a broad conical crown. Good light, likes a warm and humid maritime climate, has strong resistance to wind and sea fog, and is resistant to drought and barrenness. It can adapt to barren mountains, riverbanks, and coasts except for waterlogging, heavy saline-alkali soil, and calcareous soil. It has a well-developed root system and a high transplant survival rate. It is one of the coastal greening tree species. It is highly resistant to sulfur dioxide and is not affected by chlorine. It can be planted in polluted areas. Propagate from seeds. 7. Pinus tabulaeformis: an evergreen tree of the Pinaceae family. The crown is tower-shaped or broadly ovoid in its prime, and disc-shaped or umbrella-shaped in its old age. The bark is grey-brown with scaly cracks. The branchlets are thick and the winter buds are round. Tip tip, reddish-brown, leaves with 2 needles in a bunch, male cones orange-yellow, female cones green-purple, seeds oval, light brown, flowering period from April to May, fruits mature in October of the following year. A strong positive tree species, strong and cold-resistant, able to withstand low temperatures of -30°C. The soil requirements are not strict, and it can tolerate drought and poor soil, but cannot tolerate salt and alkali. Propagate from seeds. 8. Juniper: Cupressaceae, juniper is a tree with a spire-shaped crown. The saplings are all spiny leaves, whorled or opposite. As the plant grows older, it gradually transitions to scale leaves. The cones are nearly spherical. The next year, 4 Ripe month. It likes light, but has strong shade tolerance, cold and heat tolerance, and is not strict on soil requirements. It can grow on acidic, neutral and calcareous soils, and has certain resistance to soil drought and moisture. Sow and reproduce. 9. Poplar tomentosa: a large deciduous tree of the Salicaceae family, with a straight trunk, an obvious central main branch, and a blunt conical crown. Temperate tree species, fast-growing, strongly positive, cold-resistant, prefers a cool and humid climate, does not grow well in warm areas, has loose requirements on soil, can grow on acidic to alkaline soil, and has certain resistance to poisonous gases. Propagate by methods such as burying strips, cuttings, grafting, leaving roots, and tillering.

10. Qingyang: a deciduous tree of the Salicaceae family, with an oval crown. The bark is grey-green when young, smooth, grey-white when old, with shallow longitudinal lobes. The branchlets are cylindrical, with many yellow and dead gums in winter. The branches and leaves are hairless and the leaves are oval or oval. Egg-shaped and oval-shaped, the flowering period is in late March and the fruit ripening period is from April to May. It likes light but is slightly tolerant of shade. It likes cool and moist temperatures and is relatively cold-tolerant, but does not grow well in warm areas. It is not strict with the soil. It can tolerate drought but not flooding. It has an early germination period. It begins to sprout in March in Beijing and spreads its leaves rapidly. . It can be propagated by cuttings and sowing. 11. Weeping willow: a deciduous tree of the Salicaceae family, up to 10 meters high, with a broad obovate crown and slender drooping branches. It blooms yellow-green flowers in March and is dioecious. The capsules mature in April. Hygrogenic tree species like to grow in wetlands on both sides of river banks and will not die due to short-term flooding or roofing. It can also adapt to high dry land and lime soil. It germinates early, falls leaves late, grows rapidly, has a short lifespan, and gradually ages after 30 years. Propagation is mainly by cuttings, but seeds can also be used. 12. Willow: a deciduous tree of the Salicaceae family, with an oval or obovate crown, straight or oblique branches, and lanceolate or linear-lanceolate leaves. It likes light, is intolerant of shade, likes water and moisture, and is drought-tolerant. It can grow on dry barren sandy soil, low-humid river flats and weak saline-alkali soil, but it is most suitable for fertile, loose, moist soil. It will not grow well on heavy clay or heavy saline-alkali soil. It grows quickly, has strong germination ability, well-developed root system, can withstand long-term water immersion, takes root on dry skin, and germinates in dry spring. Cuttings take root easily, and can also be propagated by sowing, layering, and tillering. 13. Maple poplar: a deciduous tree of the Juglandaceae family. The branches have flaky piths, bare buds are densely covered with brown hairs, and there are overlapping sessile latent buds underneath. The leaves are pinnately compound, the leaf rachis is wingless, oblong, and the edges are finely serrated. , the fruit sequence is drooping, the nut is nearly spherical, with 2 oblong or oblong-lanceolate fruit wings, 2 cm to 3 cm long, spreading obliquely, the flowering period is from April to May, and the fruit ripening period is from August to September. It likes light, warm and humid climate, and is relatively cold-tolerant. It is not strict with the soil, has deep roots, obvious main roots, well-developed lateral roots, and strong sprouting and tillering ability. Propagation by seeds. 14. Elm: a deciduous tree of the Ulmus family, up to 25 meters high, with dark gray bark, longitudinal lobes, rough, gray and slender branchlets, egg-shaped oblong leaves, pointed apex, blooming in front of the leaves in early spring, and nearly round samaras. The seeds are located in the middle of the samara. The flowering period is from March to April, and the fruit ripening period is from April to June. It likes light, is cold-tolerant, drought-resistant, has strong adaptability, likes fertile, moist and well-drained soil, is not tolerant of water and moisture, but can tolerate drought, barren and saline-alkali soil. It grows quickly, has strong germination ability, is resistant to pruning, has deep main roots, well-developed lateral roots, strong wind resistance, soil retention, and strong resistance to toxic gases such as smoke and hydrogen fluoride. Propagation is mainly by sowing, but also by tillering. 15. Eucommia ulmoides: a deciduous tree of the family Eucommiaceae, with a spherical crown, smooth branchlets, no terminal buds, oval-ovate leaves, narrow oval-shaped samara, flat, flowering period in April, opening in front of the leaves or together with the leaves, and fruiting in October Ripe until November. It likes light, is intolerant of shade, and has strong cold tolerance. It can grow on acidic, neutral and slightly alkaline soils, and has certain salt-alkali tolerance. However, it can grow on soil that is too wet, too dry or too barren. Poor growth. The root system is shallow and the lateral roots are developed, with strong tillering ability and medium growth rate. Sowing, cutting, layering and tillering can be used, and root cuttings can also be used. 16. Fatong (Platanus): a deciduous tree of the Platanaceae family, with a bell-shaped crown and leaves as big as the palm of a hand, with 3 to 5 lobes. Small flowers bloom from March to April, monoecious, with aggregated spherical fruit, which matures in October. Positive fast-growing tree species are highly resistant and slightly cold-tolerant, but due to poorly developed root systems, they are easily blown down by strong winds. The soil requirements are not strict, and it can resume growth after short-term flooding. It has strong germination ability and is resistant to pruning. Sowing and cutting methods can be used. 17. Robinia pseudoacacia: a deciduous tree of the Leguminosae family, up to 25 meters high, with a straight trunk and an oblong crown. Odd-pinnate compound leaves with stipule spines under the leaf scars. White flowers bloom in May, containing aroma. The pods are flat, mature from August to September, russet, and last through winter. It is a temperate tree species that likes light, grows rapidly when young, has strong adaptability, is resistant to drought and barrenness, and is also resistant to cold. It has shallow roots, is intolerant to flooding, and has strong germination and root tillering ability. Propagate by sowing, tillering, and root cuttings. 18. Sophora japonica: a deciduous tree of the Leguminosae family, with a spherical crown and an oblate spherical shape when old. The trunk is straight and the branches and leaves are densely grown. Light yellow-green butterfly-shaped flowers bloom from June to July. They consist of large terminal panicles of multiple flowers. The pods are fleshy and bead-shaped. They mature in October and are yellow-green and will not wither through the winter. Temperate tree species, like light, slightly shade-tolerant, grow quickly when young, can adapt to dry and cold climates, and can grow normally in mildly saline-alkali soil, but they are difficult to grow in places that are too dry, barren, and windy, and often accumulate water in low-lying areas. Fallen leaves die. It has deep roots, well-developed root system, strong wind resistance and strong germination ability, which is conducive to drying out nutrients. Propagate by seeding. 19. Albizia julibrissin: a leguminous deciduous tree, up to 16 meters high, with a broad umbrella-shaped crown and an even number of pinnately compound leaves. It blooms during the day and closes at night. It blooms from June to July and is pink. A fast-growing tree species, it likes light, is slightly shade-tolerant, tolerates barrenness and drought, and has strong cold resistance. Propagate by seeding. 20. Ailanthus ailanthus: A deciduous tree of the family Quasisteraceae, with a straight trunk, a broad oval crown, glands on the leaflets, with a smell, the young leaves are purple-red, then turn green, and small yellow-green flowers bloom in May, with flat samaras and spindles. Shape, mature in September, grey-brown, not withered through winter. Fast-growing positive tree species, strong adaptability, cold-resistant, drought-tolerant, can adapt to barren slightly acidic, neutral and calcareous soils, but will not grow well in heavy clay and wetlands. Flooding will cause root rot, lateral roots are developed and often bulged. The ground has strong germination power and the roots are easy to sprout. Propagate by seeding.

21. Neem tree: a deciduous tree of the Meliaceae family, 15 to 20 meters high, with spreading branches, a nearly flat crown, dark brown bark, ovate to ovate oblong leaves, lavender flowers, fragrant, and mature. Cone-shaped compound cymes, drupe nearly spherical, yellow when ripe, persistent branches, do not fall through the winter. The flowering period is from April to May, and the fruit matures from October to November. It likes light, cannot tolerate shade, prefers a warm and humid climate, is not very cold-tolerant, is slightly tolerant of drought and barrenness, has strong germination ability, is wind-resistant, and has strong resistance to sulfur dioxide. Propagate by sowing and tillering. A deciduous tree of the family Meliaceae, with dark brown bark, peeling strips, thick branchlets, large leaf scars, oblate shape, even-numbered pinnate compound leaves, fragrant, long elliptical to broadly lanceolate leaflets, white flowers, fragrant , the capsule is oblong and spherical, and one end of the seed has membranous wings. The flowering period is from May to June, and the fruit ripening period is from September to October. It likes light and is suitable for growing in deep, fertile and moist sandy loam. It can tolerate light salting, is relatively tolerant of water and humidity, has certain cold tolerance, has deep roots, and has strong budding and tillering abilities. Propagation can be done by sowing seeds, tillering, cuttings or burying roots. 22. Pistacia chinensis: a deciduous tree of the Anacardiaceae family, with an open and flat crown. The bark is gray, the winter buds are brown, and the branches and leaves have a special smell when rubbed. Dioecious, the male flowers are light green without petals, the female flowers are purple-red, and the leaves bloom first in April. The drupe is spherical and obovate, slightly flat, mature in November, purple-blue. Positive tree species, slightly shade tolerant, tolerant of barrenness and drought, but slow growing, deep rooting, and strong tillering ability. Propagation can be done by sowing, cutting and tillering. 23. Five-cornered maple: A deciduous tree of the family Aceraceae. The leaves are often palm-shaped and have 5 lobes. The base is heart-shaped. The lobes are oval and triangular. The edges are entire. The flowers are mixed, yellow-green, with terminal corymbs. The samaras spread into obtuse angles. The flowering period is April and the fruit ripening period is from September to October. Weakly positive, slightly shade-tolerant, likes a warm, cool and humid climate, can grow on neutral, acidic and calcareous soils, has a medium growth rate, deep roots, and has few pests and diseases. Mainly propagated by seeds. 24. Triangle maple: A deciduous tree of the Acer family, with an oval crown and heterogeneous flowers of the same plant. It blooms in April and is yellow-green in cone-shaped inflorescences. The samara matures in September and is light gray-yellow. Its wings are upright and nearly parallel. It is a warm temperate tree species that likes light and is slightly tolerant of shade. It has no strict soil requirements and can adapt to acidic, neutral and calcareous soils. Slightly tolerant to water and moisture, strong germination ability, resistant to pruning and tying. Triangle maple has a well-developed root system and strong germination ability. Propagate by seeding. 24. Acer: A small deciduous tree of the Acer family, with an umbrella-shaped crown and an elegant posture. The leaves are alternately opposite. The young leaves are green and red in autumn. The small purple flowers form corymbs and bloom in April. The samaras are spread out. Obtusely rounded, curved upward, mature in October, brownish yellow. Weakly positive, tolerant of semi-shade, likes a humid and cool climate, and has no strict requirements on soil. Propagation is commonly done by seeding. 25. Yuanbaofeng: A deciduous small tree of the Acer family, with gray-yellow bark, light earthy yellow branchlets, palmately 5-lobed leaves, yellow-green flowers in terminal corymbs, flat samara, flowering in April, in front of leaves or The leaves open a little earlier and the fruit matures in October. Weak positive, likes side shade, likes to grow on shady slopes and valleys, has a certain drought tolerance, but not waterlogging. If the soil is too wet, roots will rot easily. It has strong tillering ability, deep roots, and the ability to withstand wind and snow. Not resistant to dry heat and strong sunlight, but resistant to smoke, dust and harmful gases. Propagate by seeding. 26. Horse chestnut: a deciduous tree of the horse chestnut family, up to 25 meters high, with grey-brown bark, thick branchlets, chestnut brown, large winter buds, resinous, leaflets 5 to 7, obovate-elliptical to oblong-elliptical, oblanceolate. Flowers are small in shape, with 4 petals, white, terminally cylindrical, and the capsule is spherical or obovate, yellowish brown, without thorns or tips, containing 1 or 2 seeds, shaped like a chestnut, with a large hilum, accounting for half of the seeds. , the flowering period is in May and the fruit ripening period is from September to October. It likes light, tolerates a little shade, prefers a warm climate, is also cold-tolerant, and prefers deep, fertile and well-drained soil. Propagation by sowing, cutting, and high pressure can also be used. 27. Luan tree: a deciduous tree of the Sapindaceae family, up to 15 meters tall, with grey-brown bark, slightly ribbed saplings, no terminal buds, 7 to 15 leaflets, oval or ovate-elliptical, small, golden flowers, top The panicles are sparse, and the capsule is triangular and ovate, with a pointed top. It is reddish brown or orange red when mature. The flowering period is from June to July, and the fruit matures from September to October. It likes light, tolerates semi-shade, is cold-tolerant, tolerates drought and barrenness, likes to grow in calcareous soil, and can also tolerate salt and short-term waterlogging. It has deep roots, strong tillering ability, medium growth rate, and strong ability to resist smoke and dust. Mainly propagated by sowing, tillering and root cuttings can also be used for some fast-growing tree species. Main trees: Evergreen trees: Pinus tabulaeformis, Huashan pine, Japanese black pine, Dandong cypress, Xi'an cypress, Shenyang cypress (Tabai), sand pine Fir, stink pine fir, white spruce, green spruce, etc. Deciduous trees: sycamore is preferred.

Others include poplar (big-leaf poplar), small blue poplar, small-leaf poplar, Baotou poplar, silver poplar, Xinjiang poplar, maple poplar, ginkgo, weeping willow, dry willow, tapestry willow, Korean willow, mulberry, mountain saponin, and dragon. Sophora japonica, Ulmus elm, Ulmus weeping branch, Catalpa walnut (hickory), Barberry (yellow pineapple), small-leaf Pu'er tree, big-leaf Pu'er tree, Ailanthus altissima, Luan tree, catalpa tree, purple linden, Tilia bran, Fraxinus mandshurica, Fraxinus mandshurica, Euonymus, volcanic cherry, mountain apricot, mountain peach (Beijing peach), hawthorn (large-fruited hawthorn), mountain red, rowan, water elm, larch, Japanese larch, yellow-flowered larch, North China larch, alder, Plum, Sophora japonica, Robinia acacia (Acacia), Sophora japonica (Acacia pubescens), Sophora japonica, Sophora japonica, Sophora japonica, Torch tree, Tea maple (Triangle maple), Chicken claw maple, Ingot maple (Five-cornered maple) , false-colored maple (nine-cornered maple), colored maple, escargot, buckthorn, lampstand tree, white birch, magnolia (Temple officinalis), plum, Quercus japonica, Quercus mongolica (Quercus mongolica), Quercus liaotungensis (O. liaotungensis) ) General tree species: evergreen trees: red spruce, Scotch pine, Korean pine (fruit pine), juniper, Platycladus orientalis, white pine (Beauty pine), larch, weeping juniper, etc. Deciduous trees: Beijing poplar, dragon's claw willow, steamed bun willow, and eucalyptus. Ulmus lobata, Ulmus elata (Ulma macrocarpa), Ulmus spring, Plum plum, Du Li, Sorbus pear (Autumn pear), Saponaria locust, Rhus, Euonymus, Jujube, Fraxinus microphylla, Alder tomentosa, Betula birch ( Pestle elm birch), wind birch, black birch, thousand-jin elm (thousand-jin hornbeam), cork oak, black elm, spring elm, dragon's claw mulberry, chicken mulberry, hairy hawthorn, rowan, silver maple, green maple, color Wood maple, twisted maple, sugar maple, northeastern buckthorn, trundle wood, catalpa, American ash, etc.