How does afforestation change the climate

Forests, like oceans, can regulate the climate. The transpiration of seawater and the specific heat of water reduce the temperature in summer and increase the air humidity. The evaporation of water makes liquid water change into steam, and water vapor molecules are suspended in the air, which increases the humidity of the atmosphere. At the same time, water consumes a lot of heat during vaporization, and it takes 539 calories to raise the temperature of 1 g water to 100℃. The evaporation of seawater in a large area obviously reduces the air temperature at a certain height above the sea surface and increases the humidity. The specific heat of land soil is 0.2, which is 1/5 of that of water, so the temperature on land is higher than that over the ocean. The air temperature over the ocean is low and the air pressure is high, and the air temperature over the land is high and the air pressure is low, resulting in the wind blowing from the ocean to the land and sea; At night, the land dissipates heat quickly, and the temperature is lower than that over the ocean. At this time, the wind blowing from the land produces the sea-land wind. In this way, the sea and the land constantly exchange temperature and humidity, thus adjusting the climate.

The same is true for forests to regulate climate. Green plants, such as forests, throw water away from the stomata of leaves, which is called "transpiration". This process is the evaporation of water at the stomata, just like the evaporation on the sea surface. Production 1g wood needs 150 ~ 400g water; Trees use 98% of the absorbed water for transpiration to maintain normal life activities. Hundreds of millions of stomata on the leaves of dense forests scatter water vapor into the air continuously, and its transpiration is almost the same as that of the ocean. According to the experiment, the transpiration of broad-leaved forest in summer is equivalent to that of fresh water in the same latitude and area. Due to forest transpiration, the summer temperature in forest areas is 3-4℃ lower than that in non-forest areas. In winter, because forests can prevent ground heat dissipation, the temperature in forest areas is 1-2℃ higher than that in non-forest areas. Forest transpiration increases the water vapor in the atmosphere, which increases the relative humidity of the air by 157 ~ 300%. Therefore, the exchange of temperature and humidity has taken place in forest areas and non-forest areas, which regulates the climate in non-forest areas to a certain extent.

The role of forests in regulating climate is also manifested in the following points-

1. Renewing air: The photosynthesis of forest plants should absorb a lot of carbon dioxide, and at the same time, exhale oxygen to constantly renew the air, thus maintaining the balance of atmospheric oxygen and ensuring the living conditions of people and animals.

2. Reduce the greenhouse effect: The green plants on the earth absorb about 300 billion tons of carbon dioxide every year. Studies show that the enhancement of greenhouse effect is related to forest reduction; More afforestation can reduce the greenhouse effect.

3. Disinfection: Many trees can secrete phytoncide for disinfection. According to research, there are 20,000-30,000 bacteria in the air of city 1 m3, while there are only 30-300 bacteria in the air of forest area 1 m3.

4. Generation of ionized air: The forest can generate negative oxygen ions due to the action of cosmic rays during breathing, forming ionized air with good health care and therapeutic effects.

5. Wind prevention and dust retention (sand): the forest can effectively prevent sandstorms, and the forest belt can obviously reduce the wind speed within 25 times of the forest height; The total leaf area of each tree is 50 ~ 70 times of the crown area, which cooperates with the branches and leaves to prevent sand and wind.

6. Noise reduction: Urban noise is one of the eight public hazards in modern times, which affects mood, hinders work and study, and even endangers life; Forests and hedgerows can reduce noise, while roadside forests and 30-meter-wide forest belts can reduce noise 10- 15 decibels.

Forest is the main force to balance the ecology. We should cultivate forests like raising children and let green plants be everywhere.