The forested land can store 2× 104kg more water than the forested land, and the water storage capacity is 1hm2.
1hm2 shelterbelt can protect 100 hm2 farmland from wind disaster.
The oxygen released by 1hm2 forest can be used by more than 900 people to breathe.
Noise10 ~15db can be reduced through 40m forest belt.
This forest is warm in winter and cool in summer. Compared with no forest area, the average daily temperature is about 2℃ lower in summer and 2℃ higher in winter.
Compared with non-forest areas, the number and quantity of rainfall in forest areas are 20% more.
The coniferous forest of 1hm2 can secrete 30kg antibiotics one day and night, killing bacteria such as tuberculosis, diphtheria, typhoid fever and dysentery.
A well-managed forest, 1hm2, can provide wood 15m3, industrial raw materials, fuel, feed, fertilizer and oil every year.
Forest is the foundation of the sustained, rapid and healthy development of the whole national economy, and plays an irreplaceable role in national economic construction and sustainable development.
◎ Forest ecosystem is the foundation of sustainable economic development.
Economy and ecology complement each other. Economic activities are taken from nature and returned to nature. The process of economic development can not be separated from the foundation of ecosystem for a moment. From a global perspective, the direct and partial indirect economic losses caused by ecological damage in 1996 have accounted for14% of the world GNP; From China's point of view, the direct economic loss caused by various natural disasters is as high as 200 billion yuan every year, and the grain production reduction caused by floods exceeds 654.38+0 billion kilograms. It can be seen that to achieve sustainable economic development, we must protect and build a good forest ecosystem.
Forest ecosystem is a buffer to control global warming.
Due to the recent extensive use of fossil fuels, forests have been reduced on a large scale, and the concentration of atmospheric carbon dioxide has increased rapidly, resulting in a "greenhouse effect" and a global warming trend. The results show that the reduction of forest area accounts for about 30 %-50% of the total effect of all factors in the increase of atmospheric carbon dioxide concentration. The consequences of the greenhouse effect are amazing. First of all, it will cause changes in rainfall patterns. Second, it will lead to sea level rise. Third, it will cause many plant communities growing on land to die because of temperature changes. Such changes will further promote the temperature rise and form a vicious circle of ecosystems on a global scale.
Forest ecosystem is the foundation of flood control and soil and water conservation.
The loss caused by river flooding is no less than the disaster brought by war to mankind. From 65438 to 0998, floods in the Yangtze River, Songhua River and Nenjiang River basins in China caused direct economic losses of 255.09 billion yuan. If the cost of post-disaster reconstruction is added, the amount of economic "compensation" will be even more amazing. There are countless examples of this. We always can't jump out of the vicious circle that only cares about economic development and ignores ecological protection, and the destruction of ecology must be borne by the economy.
◎ Forests have great functions of soil and water conservation.
According to research, as long as there is a litter layer of 1 cm in woodland, the sediment loss can be reduced by 94%. The sediment transport per hectare of forested land is 0.05 tons, and that of forested land is 2.22 tons, with a difference of 44 times. Forest ecosystem is a barrier to wind and sand fixation.
◎ Forests have the function of preventing wind and fixing sand.
Its windproof benefits are shown in two aspects: reducing wind speed and changing wind direction. A shelterbelt with porous structure has a windproof range of 3-5 times the height of the windward shelterbelt and 25 times the height of the leeward shelterbelt. In the windproof range, the wind speed is reduced by 20%-50%. If shelterbelts and forest nets are properly arranged, disastrous strong winds can be turned into small winds and breezes. The roots of trees, shrubs and grass can fix soil particles to prevent desertification, or change fixed sand into soil with certain fertility through biological action.
Forest ecosystem can meet human health and spiritual needs.
The purpose of economic development is to improve people's quality of material, cultural and spiritual life. The deterioration of people's health caused by environmental pollution is still borne by the economy. Forests, trees and grasslands have the functions of purifying air, reducing and controlling pollution and satisfying human physical and mental health and spiritual enjoyment. It can be said that forests and grasslands are the protectors of people's healthy body and high-quality life.
The contribution of forests to economic development is not limited to the above aspects, but also many. More prominent are:
This is the fundamental way to revitalize the mountain economy. China's mountainous areas account for 69% of its land area, and its population accounts for 1/3 of the total population. Comprehensive development and poverty alleviation in mountainous areas have become one of the main battlefields of national economic and social development. According to the characteristics of mountainous areas, the mountain must be treated first, and the forest must be promoted first. Grasping the leading role of forestry will enliven the economy and ecology of mountainous areas.
It is an important industrial sector of the national economy. Wood is recognized as one of the four major raw materials in the world and has a wide range of uses.
This is a natural reservoir. According to scientific calculation, when the roots of trees penetrate deep into the soil 1 m, each hectare of forest can store 500-2000 cubic meters of water, and each square kilometer of forest can absorb 20-40 tons of rainwater per hour, which is about 20 times that of woodland. When there is much rain, the forest can store water; When there is little rain, the forest can slowly release water, which is simply a huge natural reservoir.
China has a small forest area, little resources and uneven regional distribution. 1990, China's forest area was 654.38+246 million hectares, with a per capita of about 0. 107 hectares, while the world's forest area was about 4.049 billion hectares, with a per capita of about 0.8 hectares. The forest coverage rate in China is 12.98%, while that in the world is 3 1%. The forest stock in China is 910.40 billion cubic meters, with a per capita of about 8 cubic meters, while the forest stock in the world is about 3 1 100 million cubic meters, with a per capita of about 72 cubic meters. On the other hand, people in mountainous areas have accumulated rich experience in afforestation and forest management for a long time, and cultivated large-scale artificial forests, especially Chinese fir forests and bamboo forests in southern mountainous areas.
China is a vast country. Due to the different natural conditions in different places, there are many kinds of plants, and forest plants and forest types are extremely rich and diverse:
① Coniferous forests and mixed coniferous and broadleaved forests in Northeast China. The main natural forest areas in China are 30.94 million hectares of forests, accounting for 26.9% of the country; The forest stock is 2.89 billion cubic meters, accounting for 32% of the country; The forest coverage rate is about 37.6%. After logging, regeneration and artificial transformation, the proportion of artificial forests in this area will gradually increase. The Daxinganling Mountains in the northwest of this area are mainly larch (Larix gmelinii) forests and secondary forests of birch and Populus davidiana. In some areas, there are Pinus sylvestris var. mongolica forest, poplar and red willow (also known as red willow) along the river, and there are poor-growing Mongolian oak forests in the southeast. Xiaoxing 'anling is mainly Korean pine forest and mixed coniferous and broad-leaved forest. Besides Korean pine, conifers include larch, ichthyosis pine, Korean spruce and fir (stinky pine). Broadleaf trees include Tilia amurensis, Fraxinus mandshurica, Juglans mandshurica, pineapple, elm and mechanical trees, as well as various birch and poplar trees. The forests in Changbai Mountain area are similar to Xiaoxing 'an Mountains, but the proportion of broad-leaved tree species has increased, including Sha Song (a kind of fir) and Pinus sylvestris var. mongolica. Changbai.
② Subalpine coniferous forest and coniferous and broad-leaved mixed forest in southwest China. Located in the southeast of Qinghai-Tibet Plateau, it is the second largest natural forest area in China. The height difference of this forest area is very large, and the forest is mainly distributed in the middle and lower part of the hillside, generally below 4000 meters. There are 22.45 million hectares of forest land in the whole region, accounting for 19.5% of the whole country. The forest stock is 3.58 billion cubic meters, accounting for 39.7% of the country; The forest coverage rate is 28.3%. There are many kinds of conifers in the forest area, such as fir, spruce, larch, alpine pine and hemlock. There are many kinds of broadleaf trees, such as birch, maple and alpine oak. Tilia amurensis, Ulmus pumila, Maple, Alpine Pine and Pinus armandii are found at lower altitudes, and evergreen broad-leaved trees such as FAGACEAE and Lauraceae appear on the slopes at lower altitudes. The undergrowth plants in the forest area include rhododendron, raspberry, honeysuckle and arrow bamboo. There are many rare animals living in the forest area. Giant pandas grow in spruce and fir forests with arrow bamboo as the main undergrowth plants; There are also golden monkeys, pronghorn and so on.
Because this area is located in the upper reaches of many tributaries of the Yangtze River, the role of forests in water conservation should be paid full attention to. Forests on steep slopes and ridges should be designated as water source forests, and necessary nature reserves should be designated to protect rare species and forest types.
(3) Southern coniferous forests, evergreen broad-leaved forests and economic forests such as camellia oleifera and tung oil tree. The main trees in this area are Pinus massoniana, Pinus taiwanensis, Cunninghamia lanceolata, Cryptomeria fortunei, cypress, all kinds of bamboos (mainly Phyllostachys pubescens, Phyllostachys pubescens, Phyllostachys pubescens and many evergreen broad-leaved trees (mainly Cinnamomum camphora, Phoebe bournei, Phoebe bournei, Quercus stone, Cyclobalanopsis glauca, Schima superba, Manglietia, Dingfeng and Schima superba). In addition, there are many deciduous broad-leaved trees, such as many kinds of oak (including Quercus variabilis, Quercus acutissima, Quercus microphylla and Jatropha curcas), Zelkova schneideriana, Liquidambar formosana, Zelkova schneideriana, Pseudo-alder and Betula luminifera. Many endemic tree species in China are native to this area. Conifers include Ginkgo biloba, Metasequoia glyptostroboides, Cunninghamia lanceolata, Pinus bungeana, Cunninghamia lanceolata, Cephalotaxus fortunei and Fokienia hodginsii. Broad-leaved trees include Davidia involucrata, Eucommia ulmoides, Camptotheca acuminata, ornamental trees, Bole trees and fragrant fruit trees. Various economic forest products include camellia oleifera, tung oil tree, Chinese tallow, lacquer, palm, magnolia bark, Eucommia bark and ash. Camellia oleifera covers an area of about 3 million hectares; Tung oil is about 2 million hectares.
The mountainous area in the south is large, with good climatic conditions, and has the potential of forestry production. Vigorously developing timber forests, bamboo forests and various economic trees can provide a large number of bamboo and wood materials and various forest products, which can not only be used as raw materials for national economic construction and various industries, but also as production and living materials for the people. The south is a mountainous area with steep slopes, heavy rainfall and frequent rainstorms. Therefore, forests play an important role in water conservation, soil conservation, flood control and disaster reduction, and siltation of downstream rivers, lakes and reservoirs.
④ North China deciduous broad-leaved forest, Pinus tabulaeformis and Platycladus orientalis. The range of this forest area is roughly from southern Liaoning in the north to the north of Huaihe River in the south, including the vast mountainous areas in North China. At present, there are only scattered deciduous broad-leaved forests dominated by oak, birch and Populus davidiana and small coniferous forests such as Platycladus orientalis and Pinus tabulaeformis. A few Fraxinus mandshurica, maple, linden and poplar grow in parts of the valley with good water conditions. There are also small pieces of Larix principis-rupprechtii, spruce (with green stems and white stems) and a few firs in higher mountainous areas. This area needs to vigorously protect and cultivate forests, produce wood and fuelwood, conserve water and maintain soil.
⑤ South China tropical monsoon forest. Distributed in the south of the Tropic of Cancer. The main forest areas are Hainan Island and South China Sea Islands, southern Taiwan Province Province, Honghe Hani and Yi Autonomous Prefecture and Xishuangbanna. The forest basically belongs to tropical monsoon forest, and the root phenomenon is obvious in the wet valley. There are tall tree ferns and palm plants under the forest, and orchids, ferns and Araceae plants are attached to the trunk, showing the landscape of tropical rain forest. The forest area is rich in forest plants, including Dipterocarpaceae trees, such as plum blossom, bole, Dipterocarpaceae and ginkgo biloba, and tropical trees, such as butterfly tree, Face, longan, Azadirachta indica, Azadirachta indica and Adiantum ovatum. There are also wild flowers in Xishuangbanna and the southernmost part of Guangxi. In addition, Lu Junsong and Pinus yunnanensis are also distributed in Hainan Island and southern Yunnan. In the mountainous areas with higher altitude, there are evergreen broad-leaved forests dominated by evergreen FAGACEAE trees. The valley area is low in altitude, with little rainfall, and the drought phenomenon is obvious, such as the dry tropical forest with thick bark and closed flowers and trees, Albizia Albizia (Haig, white dove) and Dendrocalamus spinulosus, similar to the savanna in the south of Hainan Island.
The tropical forest region of South China is the region with the most abundant heat in China, but the dry season is long, with occasional low temperature below 10℃. Therefore, measures should be taken to prevent dry wind and low temperature. Before planting rubber in Hainan Island, planting windbreaks received good benefits.
⑥ China's forests are not only distributed in the above-mentioned forest areas, but also in the vast arid and semi-arid areas, oases, river banks and mountainous areas with a certain height in northwest China, such as Populus euphratica forests in Tarim River Basin, Tianshan Mountain and Qilian Mountain. In addition, there are plains, basins and deltas in the east of China, and the original natural forests have been destroyed for a long time, with only sporadic tree species and small jungles. Since the 1950 s, farmland shelterbelts, intercropping between clothes and trees have been established. The forest coverage rate in many counties has reached 10 ~ 15%. Farmland shelterbelts in these areas have played a great role in protecting farmland, planting trees around them has improved and beautified the environment, and provided wood, fuelwood and various forest products needed locally. By 1989, the planted area in China reached 38.3 million hectares, accounting for 1/3 of the total planted area in the world.