Pterocarya stenoptera grows rapidly and has strong adaptability, which is the main greening tree species in the plain lake area.
[Morphological characteristics]
Deciduous trees, branchlets separated by pith. Bare buds pedunculate and densely covered with rusty brown hairs. Even pinnate compound leaves, sparse and odd, leaf axis with narrow wings. In April, yellow-green catkin flowers are monoecious, with male inflorescences in leaf axils and female inflorescences at the top of branches. Nuts are nearly spherical, with two wings spreading obliquely, which are shaped like ingots, hanging on the top of new branches in a string and maturing in August (see color picture 42).
[distribution]
Widely distributed in Liaoning, Hebei and Shaanxi in the north, Guangdong and Guangxi in the south, Jiangsu and Zhejiang in the east and Sichuan and Guizhou in the west.
[habit]
Positive tree species, slightly tolerant to shade and growing rapidly. I like warm and humid climate, and I am not strict with the soil. Both acidic and neutral soils can grow. Water and humidity resistance, not afraid of flooding, although it can adapt to dry places, it is easy to age. Strong germination ability, the sprouted branches after cutting grow faster than the seedlings at the same time.
[Propagation, Cultivation and Maintenance]
Seeds are propagated, harvested in August, peeled, dried, stored in bags or mixed with sand. It is best to sow in autumn or spring. Before and after sowing in early winter, seeds can germinate and be unearthed early, and spring sowing can be carried out in early spring until it rains. Before sowing, the seeds were soaked in warm water at 40℃ for 24 hours to promote orderly germination. Commonly used drilling, sowing amount110 ~150kg/ha. Unearthed about 20 days after sowing. When the height of seedlings is as high as 10 cm, it should be thinned, and the spacing between plants should be 15 ~ 20 cm. Do a good job in fertilizer management and pest control during the growing period, and the height of annual seedlings can reach 1 00 cm. The transplant time should not be too early, and it should be around Tomb-Sweeping Day, otherwise it will wither easily and should be used with the transplant. Overwintering with the wind is not only easy to freeze new shoots, but also has a low survival rate. The branches of Pterocarya stenoptera are so thick that it is difficult to straighten the trunk without proper pruning. Pruning should start from the base of lateral branches, and the incision should be flat to promote healing, so as not to cause trunk rot and hollowness. The pruning season should be in winter, not in spring. The pruning intensity should be higher in 2-3 years, that is, all the thick side branches at the lower part should be pruned, and the pruning intensity should be appropriately reduced in 4-5 years. When the height of the tree is about 10 m, the pruning strength should generally be kept at 1/3 ~ 1/2 of the height of the tree. After pruning, the dormant buds on the trunk are easy to germinate and should be erased in time.
The main pests and diseases are: maple witches' broom, camphor tree parasitism, silkworm moth, litchi moth, Anoplophora yunnanensis, sawfly, diamondback moth, sapium sebiferum, yellow thorn moth and so on. Control methods: ① Thoroughly cut off Cinnamomum camphora parasitized for years, including external roots and internal roots, and cut off the big roots with tufted branches. ② Insecticides such as trichlorfon or dichlorvos are sprayed on moths and butterfly larvae. (3) trapping and killing the adults of Anoplophora longicorn with artificial light, and blocking the insect holes with cotton balls soaked with pesticides such as cartap or phosphoramide.
[Appreciation and Application]
Pterocarya stenoptera has a broad crown, dense branches and leaves, rapid growth and strong adaptability, and can be used as roadside trees and highways for greening. Suzhou Gardens, Hangzhou West Lake and Nanjing Scenic Area are all very common. Pterocarya stenoptera has developed root system and is an excellent tree species for dike reinforcement and revetment. It can be planted in low-lying areas and streams, or on lawns and slopes alone, with shade everywhere. It is an excellent greening tree species for rivers and lakes.
9. weeping willow (willow of Salicaceae)
Weeping willow.
Willow branches are slender and drooping, dancing with the wind, swaying, beautiful and unique, and are one of the characteristic tree species in Jiangnan gardens in China.
[Morphological characteristics]
A deciduous tree with slender drooping branchlets, narrow lanceolate leaves, long and sharp tips, white surface and pubescent petioles. Dioecious, catkin. Yellow-green flowers bloom in March. The fruit ripens in April. There are many similar species, mainly including:
Salix matsudana S.matsudana is shaped like a weeping willow, with straight trunk and upward branches, strong cold resistance, rapid growth and beautiful tree shape, and its distribution range is wider than that of weeping willow, centering on the Yellow River basin.
Curved willow is a small shrub-like tree and a variety of willow. Its branches are curled up and its ends droop slightly, like a dragon claw, and its posture is very unique. It is one of the commonly used tree species in gardens (see color picture 43).
Chaenomeles salicifolia branchlets are widely distributed, with wide and short leaves and half-hearted leaves, and the age of the tree can reach more than 100 years.
Silver willow is a small shrub with spreading branchlets, nearly round leaves and silvery white hairs on the back.
Rosa laevigata is a clone cultivated by Jiangsu Institute of Forestry Science, with drooping branches and yellow-green leaves in the growing season, which has unique ornamental value.
[distribution]
It is cultivated in all provinces and regions of China. Most countries in Asia, Europe and America have a long history of introduction and cultivation.
[habit]
Wet positive tree species. Born in wetlands on both sides of the river bank, it will not die if it is flooded for a short time. High dry land and calcareous soil can also adapt. Germination early, defoliation late, growth fast, but not as cold-resistant as Salix matsudana. Life is short.
[Propagation, Cultivation and Maintenance]
The propagation of weeping willows is mainly cuttage, which is carried out in early spring. Select excellent plants with fast growth and few pests and diseases as cutting mother trees. Before germination, cut off the 2-3-year-old branches and cut them into 15 cm for cutting. Directly insert, fully water after inserting, keep the soil moist at all times, wipe buds and weed in time, topdress for 3 ~ 4 times after rooting, and pay attention to the prevention and control of pests and diseases at seedling stage. Weeping willows are mostly used for the greening of surrounding areas (i.e. forests, houses, roadsides and rivers) and parks, and large seedlings with a height of 2.5-3 meters and a ground diameter of 3.5 cm or more should be selected. Transplanting should be done after defoliation in winter and before bud germination in early spring of the following year. After planting, fully water and erect pillars.
The main pests and diseases are: willow leaf rust, root-knot nematode disease, willow gall midge, willow oyster scale, willow thorn mealybug, willow wart aphid, yellow-breasted moth, willow beetle, Anoplophora glabripennis, snow borer, blue-eyed moth, water green moth and so on. Prevention and control methods: ① Spraying sulfur mixture or weixiuling at the early stage of rust. ② Apply nematicides, such as Mianlong, in Liumiaogou of nursery. ③ Brush the affected area of gall midge with omethoate or dichlorvos, and make several cuts with a knife to facilitate the penetration of liquid medicine. (4) Kill the adults of Anoplophora longicorn, block the wormhole of Anoplophora longicorn with a cotton ball dipped in dichlorvos or zinc phosphide, and poison the larvae. ⑤ Spraying omethoate, phoxim, iminophosphate, malathion, etc. In the nymph and larval stages of scale insects.
[Appreciation and Application]
Weeping willows are most suitable for planting on river banks and lakes, where branches rub against the lake and reflect in the water, not caused by the wind. Peach trees are often planted in Jiangnan gardens, with pink and green, bright flowers and more beautiful spring. Willow likes humidity and can be used as a street tree, a shade tree and a wave-proof revetment tree in high water level areas. It has certain resistance to toxic gases and is also suitable for greening factories and mines. However, in view of the flying catkins, it is best to choose male plants as urban street trees or plant them near precision instrument factories.