How do trees produce oxygen, and how do plants produce oxygen?

1. Forests are natural"Oxygen plant"。Trees and forests through photosynthesis.

The continuous production of oxygen maintains the oxygen balance of the earth. One hectare of forest releases 750 kg of oxygen per day, which can meet the needs of 1,000 people at a time. The world's forests provide 60% of the clean oxygen to the air every year.

Without forests, the atmosphere would run out of oxygen in about 3,000 years.

2. Forests are airy"Purifiers"。Trees and forests can trap and adsorb dust and absorb sulphur dioxide.

Harmful gases such as hydrogen fluoride kill germs and reduce noise, thereby purifying the air. The dust reduction rate of forest land is 37%-60% compared with open land. The difference in bacterial content per cubic meter of air in cities with forests is more than 85% compared with those without forests.

Noise can be reduced by 10-20 dB through a 40-meter-wide forest belt.

3. Forests are climatic"Regulators"。Forests can absorb large amounts of carbon dioxide through tree photosynthesis.

Slow down the global warming effect and curb global warming.

One hectare of broadleaf forest absorbs 1 tonne of CO2 per day during the growing season. Forests also improve regional microclimates. Since the establishment of Saihanba Machinery Forest Farm in our province, the forest coverage rate has increased from 20% to 78%, and the annual precipitation has increased from 417 mm to 530 mm.

In other parts of North China, due to the loss of forests and other reasons, the annual precipitation is more than 100 mm lower than that in the 70s of the last century.

4. Forests are terrestrial"Reservoirs"。"The mountains are full of trees, which is equivalent to building a reservoir, and it can swallow it when it rains, and it can spit out when it doesn't rain"。Forests have huge water storage and soil retention functions.

A 100,000 mu forest holds as much water as a 2 million cubic meter reservoir. If there were no forests on Earth, the consequence would be that 70 per cent of the land's freshwater would flow into the sea, and humanity would have a freshwater crisis.

5. Forests are human"Longevity agent"。Because trees and forests provide people with clean air, clean water, and a beautiful environment, trees live a long life. The longevity towns of the world are all wooded and densely vegetated. Bama County, Guangxi.

The average million population has more than four times the world standard with centenarians, and the fundamental reason is that there are many trees and the ecology is good.

6. Forests are the earth"Resource Library"。Forests are the habitats for the survival and reproduction of a variety of animals and plants, and are the world's richest reservoir of biological and genetic resources. 50% of the planet's existing species are found in forests.

Forests can not only provide people with timber directly, but also provide dried and fresh fruits, woody grains and oils, medicinal herbs, edible fungi and industrial raw materials.

Through photosynthesis, carbon dioxide is absorbed and oxygen is released.

Photosynthesis, that is, photosynthesis, is a biochemical process in which plants, algae and certain bacteria, under the irradiation of visible light, undergo light reaction and dark reaction, use photosynthetic pigments to convert carbon dioxide (or hydrogen sulfide) and water into organic matter, and release oxygen (or hydrogen). Photosynthesis is the sum of a series of complex metabolic reactions, which is the basis for the survival of the biological world and an important medium of the earth's carbon and oxygen cycle. Photosynthesis is a biochemical process in which green plants use photosynthetic pigments such as chlorophyll and certain bacteria (such as halophilic archaea with purple membrane) use their cells themselves to convert carbon dioxide and water (hydrogen sulfide and water for bacteria) into organic matter and release oxygen (hydrogen gas released by bacteria) under the irradiation of visible light.

Plants are called producers of the food chain because of their ability to produce organic matter from inorganic matter and store energy through photosynthesis. Through consumption, consumers in the food chain can absorb the energy stored by plants and bacteria with an efficiency of about 10% to 20%. For almost all living beings in the biological world, this process is the key to their survival.

And in the carbon-oxygen cycle on Earth, photosynthesis (which keeps oxygen and carbon dioxide levels relatively stable) is essential.

Under the exposure of sunlight, green plants absorb carbon dioxide and water from the outside world, and use light energy to produce organic matter mainly carbohydrates and release oxygen in chloroplasts. At the same time, light energy is converted into chemical energy and stored in the organic matter produced. This process is called photosynthesis.

The reaction formula of photosynthesis can be expressed as follows: The energy stored in carbohydrates is in sunlight, so photosynthesis must have light to take place. The carbohydrates made by photosynthesis are first of all glucose, but glucose soon turns into starch, which is temporarily stored in chloroplasts and later transported to various parts of the plant body.

In addition to carbohydrates produced by photosynthesis, plants also contain organic matter such as proteins and fats. Proteins and fats are mostly carbohydrate-based and undergo complex changes. In the process of making proteins, nitrogen-containing inorganic salts are also required as raw materials.

Encyclopedia The organic matter produced by photosynthesis, except for a part used to build the plant body and respiration consumption, most of it is transported to the storage organs of the plant body for storage, and the food and vegetables we eat are these stored organic matter. Therefore, the products of photosynthesis are not only necessary for the life activities of plants themselves, but also directly or indirectly serve other organisms (including humans) and are used by these organisms. The oxygen produced by photosynthesis is also one of the most abundant oxygen in the atmosphere.

The water absorbed by the roots from the soil into the plant body, except for a small part for plant life and photosynthesis to produce organic matter, most of it becomes water vapor, which evaporates into the air through the stomata on the leaves, a phenomenon called transpiration. Leaf transpiration and water are closely related to the life of the plant body. Every plant has many leaves, and the total area of the leaves is large and absorbs a lot of sunlight, which is beneficial for photosynthesis.

However, when plants absorb a lot of sunlight, the body temperature of the plant body will continue to rise, and if these heat accumulate in large quantities, the plant will be burned. During transpiration, a large amount of water in the leaves is constantly turned into vapor, which takes away a lot of heat, thereby reducing the body temperature of the plant and ensuring the normal life of the plant. In addition, the transpiration of water in leaves also promotes the rise of water in plants and inorganic salts dissolved in water.

Here's how oxygen is made:

The main components of air in the air-chilled separation method are oxygen and nitrogen. The preparation of oxygen from air using the different boiling points of oxygen and nitrogen is called air separation. The air is pre-cooled and purified (removing a small amount of moisture, carbon dioxide, acetylene, hydrocarbons and other gases and impurities such as dust from the air), and then compressed and cooled to become liquid air.

Then, taking advantage of the difference in the boiling points of oxygen and nitrogen, the liquid air is evaporated and condensed several times in the distillation column to separate the oxygen and nitrogen to obtain pure oxygen (purity) and pure nitrogen (purity. If you add some additional equipment, rare inert gases, such as argon, neon, helium, krypton, xenon, etc. It can also be extracted if it is very small in the air.

The oxygen produced by the ASU is compressed by a compressor, and the compressed oxygen is stored in high-pressure cylinders or directly piped to factories and workshops. Oxygen production in this way requires large-scale complete sets of equipment and strict safety operation technology, but the output is high, and thousands of cubic meters of oxygen can be produced per hour.

And the raw materials consumed are just air that does not need to be purchased, transported, stored in the warehouse. Therefore, since the development of the first cryogenic air separation oxygen generator in 1903, this oxygen production method has been widely used.

The molecular sieve oxygen method (adsorption method) uses a special molecular sieve to separate oxygen in the air by taking advantage of the fact that nitrogen molecules are larger than oxygen molecules. First of all, the compressor forces the dry air to enter the vacuum adsorber through the molecular sieve, so that the nitrogen molecules in the air are adsorbed by the molecular sieve, and the oxygen enters the adsorber and makes a fuss.

When the oxygen in the adsorber reaches a certain amount (the pressure reaches a certain level), the oxygen outlet valve can be opened to release the oxygen. After a period of time, the nitrogen adsorbed by the molecular sieve gradually increases, the adsorption capacity decreases, and the purity of the oxygen produced decreases.

It is necessary to use a vacuum pump to pump out the nitrogen adsorbed on the molecular sieve, and then repeat the above process. This method of producing oxygen is also called adsorption. Small oxygen concentrators using adsorption method have been developed and widely used in household oxygen concentrators.

An average tree can produce about 700 grams of oxygen per day. It has been determined that 1 hectare of forest can release 750 kg of oxygen per day.