Qinghai plateau plants

From the geographical composition of plant species, there are obvious regional differences in different regions of the Qinghai-Tibet Plateau. The low-altitude areas in the southern margin of the Qinghai-Tibet Plateau and the southern wing of the East Himalaya belong to the paleotropical flora, which is dominated by tropical geographical elements. Although there are many species, there are few species in each genus, which shows that it is located in the northern margin of paleotropical flora and belongs to tropical Asian elements, and its origin is mostly ancient. For example, Cephalotaxus Cephalotaxus of Cephalotaxus, Celastrus Celastrus of Celastrus, Abidingfeng of Hamamelis, Lonicera japonica of Caprifoliaceae, etc. The forest flora in the southeast of the plateau is mainly composed of China-Himalayan elements, and contains a large number of woody plants, which constitute various types of forests, such as some evergreen trees of FAGACEAE, FAGACEAE and Lauraceae, representative trees of alpine oak plants and coniferous forests, such as alpine pine, Qiao Song, various Abies, spruce, etc. The modern distribution center of rhododendrons is here.

Within the plateau, the Qinghai-Tibet Plateau is dominant. It has a young and independent history, and many species and genera gradually adapted to the cold and arid ecological conditions during the intense uplift of the plateau. Typical representative plants such as Artemisia capillaris, Stipa purpurea, sand-fixing grass, Artemisia Tibetan, Ceratoides, etc. The arid areas such as northwest plateau and Qaidam basin are dominated by desert elements in Central Asia, such as Ceratoides arborescens, Ephedra, Hedyotis diffusa, Salsola salsa and Stipa arenaria. Typical temperate and alpine components, such as Rumex, Festuca arundinacea and Polygonum viviparum, are widely distributed on the plateau, and are often components of alpine shrubs and meadows.

Broad-leaved forest composed of broad-leaved trees is widely distributed in humid and semi-humid areas in the southeast of Qinghai-Tibet Plateau. There are many types of them, which are closely related to ecological and geographical conditions.

Tropical evergreen rain forest and semi-evergreen rain forest are distributed in the southern wing of the East Himalayan Mountains, with an altitude of 1, 000- 1, 100 meters, with tall trees and dense forests, usually as high as 30-40 meters. The main tree species are tropical, and the evergreen rainforest is composed of many trees such as Dipterocarpaceae, Moraceae and Siluriaceae. Semi-evergreen rain forest consists of lazy people in Li Qian and Ding Feng. The composition of these tropical forests is complex, and the levels in the forests are not obvious. The bark of many trees is smooth, grayish white or grayish brown, which is particularly eye-catching. Some trees have roots protruding from the ground, and some trees, such as verbena, have huge fruits, which grow directly on the trunk and have thick branches. This is the phenomenon of "old stems blooming". There are many large lianas and epiphytes in the forest, mainly composed of Araceae, Palmaceae, Orchidaceae and Piperaceae, as well as tropical ferns and mosses, including unicorn leaves with large leaves, Gesneriaceae with red corolla and orchids with pleasant fragrance. Evergreen broad-leaved forest is widely distributed in the south wing of the central and eastern Himalayas and Chayu area. It is composed of evergreen trees such as Castanopsis fargesii, Cyclobalanopsis glauca and Lithocarpus, Lauraceae and Magnoliaceae. It has a round and wavy crown, a large forest crown, a height of 20-30 meters, many layers, and many epiphytes and climbers. Some woodlands are very wet, and the stones or trunks on the ground are covered with moss, which has the characteristics of "fog forest" or "moss forest" Hard-leaved evergreen broad-leaved forest is a forest composed of Quercus species of FAGACEAE, such as Quercus montana, Quercus chuandianensis and Quercus flavescens. Different from the above evergreen broad-leaved forest tree species, Quercus variabilis has the characteristics of xerophytic ecological adaptation, with evergreen leaves, hard leathery, small and medium leaves, sharp spines or teeth at the edge of leaves, smooth leaves and short yellow or gray hairs on the back of leaves. The trunk is curved, the wood is hard, the bark is thick, and the branches are numerous and dense. The height of the tree is generally 15-25m, and the hierarchical structure is relatively simple. This kind of forest is yellow-green or yellow-brown, and yellowish pine cones are often hung on the branches of the crown. Deciduous broad-leaved forest is suitable for ecological conditions with cold climate, and it is mostly composed of positive tree species that shed leaves in winter, such as birch, alder and poplar. Betula scabra forest is more common in the upper part of the forest; Dry wax gourd in Alnus cremastogyne is a fast-growing tree species with wide adaptability, and often forms secondary forests at lower altitudes. The mixed forest of Populus davidiana and Betula platyphylla is a kind of natural regeneration forest after the destruction of coniferous forest, which is mainly distributed in the forest area in the southeast of the plateau. In addition, there is a small piece of Quercus liaotungensis forest on the shady slope in the eastern mountainous area of Qinghai.

These broad-leaved forest types have certain rules on the requirements of temperature and water conditions. With the change from warm humidity to cold humidity or cold drought, they generally change from tropical rain forest to evergreen broad-leaved forest to broad-leaved evergreen broad-leaved forest to deciduous broad-leaved forest. The forest is composed of many species, the forest structure is self-propagating and simple, the level is reduced and the height is shortened. Conifer forest

Conifer forest

Coniferous forest is the most widely distributed forest type in Qinghai-Tibet Plateau, among which evergreen coniferous forest includes pine forest, hemlock forest, spruce forest, fir forest and cypress forest. Deciduous coniferous forest has larch forest. The trees in coniferous forests are usually tall and straight, with high volume per unit area, which can provide economic wood and a large number of forest by-products, and have important economic value. Plateau coniferous forests are mostly distributed in the mountainous areas in the upper reaches of rivers, which have obvious ecological functions and benefits in soil and water conservation and environmental improvement.

Pine forest is mainly composed of Pinus yunnanensis, Pinus alpine, Qiao Song and Pinus longleaf. The first two species are distributed in Chayu and Hengduan mountain areas, and the last two species are distributed in the southern wing of Himalayas. They are drought-resistant and barren-tolerant positive tree species with strong adaptability. They usually grow rapidly, renew well and have strong fire resistance. Most of them form forests with few layers, good light transmittance and neat forest appearance on sunny and semi-sunny slopes. Taking Yunnan pine forest growing in Chayu area as an example, the average height of 130-year-old stands is close to 50 meters, and the volume per hectare reaches 1 1,000 square meters, which exceeds the Korean pine forest with superior growth conditions in Xiaoxing 'anling area of Northeast China.

Hemlock forest, which likes humidity, is mainly distributed on the hillside in the humid area on the southern edge of the plateau. Hemlock is vigorous and tall, up to 30-40 meters, and its drooping branches set it off more magnificently. Hemlock forest is humid, and there are many trees, shrubs and herbs in the lower layer. The trunk is covered with moss, which seems to be wrapped in a thick and soft green felt.

Forests composed of spruce and fir are generally called dark coniferous forests, which are widely distributed in mountainous areas in the southeast of the plateau. Abies likes wet and cold, the tree is 20-30 meters high, there are many trees and shrubs in the forest, the moss layer on the surface is developed, and the branches are often hung with long yellow-green pine branches, dotted with dark green forest crowns.

Spruce forests are usually distributed at a lower altitude than fir forests and can grow on sunny slopes in humid areas. Because of cold tolerance and drought tolerance, it often dominates on both sides of the watershed in Hengduan Mountain area, forming the upper limit of the forest and the northwest edge of the forest area. Common forests are Linzhi spruce forest and western Sichuan spruce forest. Picea crassifolia forest grows in the eastern Qilian Mountains on the northern edge of the Qinghai-Tibet Plateau. In the West Kunlun Mountain to the west of Yecheng, spruce forests in Ling Xue are scattered on the shady slopes of wet canyons.

The distribution of cypress forest is limited. Giant cypress is a tree species in Langxian County in the middle reaches of Yarlung Zangbo River, which is suitable for sand and drought resistance and has a unique style. In Jinchuan and Marcand in the upper reaches of Dadu River, cypress trees in Minjiang River are dominant, and most of them grow on the steep slopes of narrow valleys. Sabina vulgaris forest is mostly found in the sunny slope of the upper part of the forest belt in Hengduan Mountain area, with Sabina vulgaris as the main species. It is a typical drought-resistant, barren-resistant and cold-resistant forest type, mostly sparse forest with an altitude of about 10 m, and its structure is relatively simple. The eastern and northeastern parts of the plateau are dominated by Qilian around Berlin.

Larix gmelinii and Larix gmelinii are the main deciduous coniferous forests. The former is distributed in Hengduan mountain area, and the latter is mainly in the mountainous area on the southeast edge of Tibet. Cold-resistant and barren-tolerant, with low requirements for soil conditions and high distribution altitude. Some of them also form the upper limit of forests or stubbornly grow on moraines.

Ecology of various shrubs

Shrubs are all over the Qinghai-Tibet Plateau. They cover a small area, but there are many kinds. There are evergreen leatherleaf shrubs and evergreen coniferous shrubs mainly distributed in the southeast, as well as different types of deciduous broadleaf shrubs scattered in the plateau, succulent spiny shrubs in arid valleys and halophytic shrubs in desert areas.

From April to June every year, rhododendrons with red, purple, white and yellow flowers can be seen on the mountains in the southeast of the plateau, forming a colorful mountain flower world. Their species and ecological characteristics vary from place to place. On the shady slope of the mountain next to the forest belt, a tall and scaleless rhododendron shrub, represented by Rhododendron campanulata, is growing, with lush foliage and pink and white rhododendrons in full bloom. Under the ecological effect of snow in winter and spring, they first grow along the slope, and then stand 2-4 meters upright, forming a closed and impassable shrub covered with 3-5 cm thick moss, which is very humid. In the open mountains, rhododendron shrubs are mostly composed of scaly rhododendrons, with short plants and small branches and leaves, and the height is between 0.8 and 0.2 meters. There are many kinds of rhododendrons in Hengduan mountain area, which are generally considered as the hometown of rhododendrons and connected to the east Himalayas to the west. This area contains most kinds of rhododendrons, and its most primitive groups are also distributed here. From here to the interior of the plateau, the species of rhododendron shrubs are reduced and the scenery is monotonous. It can reach the east Qilian Mountain in the north and the east of Gangdise Mountain in the west. In sharp contrast with the rhododendron shrub, Sabina vulgaris shrub is drought-tolerant, distributed on the sunny slope in this area, and often forms a dark green disk with a diameter of about 1- 1.5 meters, which is called "Sabina vulgaris" in some places. This evergreen coniferous shrub is more cold-resistant and drought-tolerant, and its distribution range is more extended to the hinterland of mountainous areas than rhododendron shrub, so it has plateau characteristics. Among deciduous broad-leaved shrubs, Chimonanthus praecox is the most widely distributed, not only in the humid and semi-humid mountainous areas from the East Qilian Mountains to the Himalayas, but also in the semi-arid hinterland of the plateau. Their yellow flowers bring warm spring scenery to the monotonous scenery there. This shrub can be distributed to 5500-5600 meters above sea level, and it is the shrub with the highest altitude distribution. However, they are dwarfs in the bushes, only 3-5 cm tall. Spike shrubs in Tibet are widely grown on slopes, alluvial fans or sandy land along the middle reaches of the Yarlung Zangbo River. It is generally 50- 100 cm high, with wide ecological range and strong adaptability. It is a group-building species of mountain shrub grassland, which blooms blue-purple iris in May every year, adding color to the dry season in late spring. Because of the lack of fuel here, this shrub has become the main object of firewood collection, which makes soil erosion more and more serious. Alpine deciduous broad-leaved shrubs composed of various Caragana also occupy a prominent position in the shrub vegetation family. Shrubbery dominated by Caragana can be seen on the foothills and slopes of the southern Tibetan Plateau and Ali area. They grow very low and form a disk with a diameter of 1-2 meters, which is scattered on the gentle plateau or hillside, forming a unique landscape. Caragana shrub is widely distributed in humid and semi-humid mountainous areas. In late spring and early summer, its pink flowers are particularly eye-catching, which often makes people forget its daunting and thorny plants. Drought-tolerant shrubs are composed in forest areas, which are obviously different from rhododendron shrubs in humid mountainous areas. They are dry valley shrubs that grow on the slopes on both sides of the deep valley bottom. It is mostly composed of spiny and drought-tolerant shrubs, such as succulent spiny shrubs such as Bawangbian and cactus at low altitude. In the valley at a slightly higher altitude, there are shrubs such as bauhinia, rhamnus and Nitraria. In late spring and early summer, the seasonal drought in deep valleys is obvious, and the tender leaves in shrubs germinate late. The rejuvenation grass (Selaginella Selaginella) among shrubs blooms quickly and turns green when the rainy season comes, and it is full of vitality. Tamarix halophytes grow in the floodplain, low terrace and fan-edge groundwater overflow zone of Hongliubao in Qaidam Basin. Fixed and semi-fixed sandbags are formed on the southwest edge of the basin, with a height of 5-7 meters, commonly known as "Hongliubao". In addition, in the salinized sandy land on the edge of the lake basin, the groundwater level is shallow and there are tufted Nitraria shrubs. Nitraria tangutorum is flourishing, and its base often forms shrub sandbags due to sand accumulation, which constitutes a unique landscape.

Alpine meadow is widely distributed in Qinghai-Tibet Plateau, and consists of mesophytes and perennial herbs suitable for low temperature. It is like a green carpet, distributed in the slow cutting plateau in the central and eastern regions. Artemisia meadow is the most widely distributed, mainly Artemisia plants. Its plants are low and densely clustered, with the characteristics of vegetative propagation of ground buds and short rhizomes. It can adapt to the unfavorable conditions such as short growth period, frequent thawing, low temperature and cold, and is a unique type to adapt to the alpine and arid ecological environment of the mainland plateau. The most typical meadow is Artemisia ordosica, which covers more than 80-90%. The grass layer is low, only 3-5 cm, with simple structure, inconspicuous hierarchical differentiation, monotonous scenery and yellow-green seasons. The biomass of this grassland is very low, but Artemisia capillaris is soft, nutritious and delicious. At the same time, it is resistant to grazing and trampling, which is a good natural grassland suitable for grazing yak and Tibetan sheep. Except in the semi-humid areas of the central and eastern plateau, under semi-arid and arid conditions, wormwood meadow is poorly developed, and it is common in the shady slopes of high mountains or only distributed in patches. Artemisia ordosica in the southeast transition section of Qiangtang Plateau

Potentilla chinensis

Meadow contains grassland plants such as Stipa purpurea and has the characteristics of grassland meadow.

There are Polygonum rotundifolia, wormwood meadow and weed meadow composed of Polygonum rotundifolia, evergreen, Potentilla, total yellow flower and wormwood. The grass layer is as high as 15-20 cm, and pink, yellow, blue and purple flowers bloom in summer, which adds charming scenery to the alpine region. On the high mountains in the north-central Hengduan Mountains, this grassland is mostly where Tibetan compatriots graze in summer. On the light green carpet, black tents are scattered all over the place, which has a unique flavor. Alpine meadows, especially wormwood meadows, have densely staggered roots, forming a dense felt-like turf layer above the soil, with a thickness of more than 10 cm. Some locals dig it for building materials, or pile it in the tower to dry it for fuel. Wormwood swamp meadows are widely distributed in lakesides, intermountain basins, low terraces on both sides of rivers and phreatic overflow zones at the foothills of Qinghai-Tibet Plateau. These areas have high altitude, cold climate and gentle terrain, and frozen soil has become an impermeable layer underground, so surface water has formed a stagnant zone. The soil is too wet, which has been thawed for a long time to form a "tower head"-shaped frost heaving mound and a hot-melt depression with accumulated water. There are swamp meadows represented by Tibetan wormwood and Artemisia macrophylla, as well as black-brown Carex, donkey's hoof and crested chrysanthemum. The community has dark green appearance, dense plant growth, thick leaf layer, high grass yield and good palatability. After entering the winter, Tibetan wormwood is not easy to be covered by snow because of its tall plants, which is convenient for livestock to eat; Because there are many parasites and pathogens in the pond and it is too humid, sheep are prone to diseases such as hoof rot. Not suitable for grazing sheep, but most suitable for yak grazing.

Zoige area in northwest Sichuan has gentle terrain, too much surface water, and a large area of swamp meadows and swamps, making it difficult for people and animals to pass. This is the "grassland" that the Red Army walked very hard on the way to the Long March. The swamp in moss vegetation is a typical type here, and it often forms a complex distribution with Artemisia ordosica meadow. Due to the slow decomposition of organic matter and the acceleration of peat accumulation, the peat layer in Zoige swamp is 2-4 meters thick. In areas above 4000-4500 meters above sea level, the peat layer is very thin, only about half a meter. Even on the snow line, as long as there is soil, there is alpine moss meadow, which is only millimeters and centimeters thick, just like green fragments stuck in the snow.

I hope it helps you. O(∩_∩)O