With the development of society, people increasingly realize that forests have the functions of absorbing carbon dioxide and releasing oxygen, taking medicine, removing dust, sterilizing, purifying sewage, reducing noise, preventing sandstorms, regulating climate, indicating and monitoring toxic substances and so on. So many people began to feel the joy of the big forest in nature and realize the various benefits of the big forest to the human body. When you step into the green forest, you will suddenly feel comfortable and fatigue will disappear. Green in the forest not only brings beautiful scenery to the earth, but also acts on people's central nervous system through various senses, regulating and improving the body's function, giving people a feeling of tranquility, comfort, vitality and spirit, thus improving health.

According to the investigation, the green environment can reduce the secretion of human adrenaline and the excitability of human sympathetic nerve to a certain extent. It can not only make people calm and comfortable, but also reduce the skin temperature of human body by 1℃-2℃, reduce the pulse by 4 -8 times per minute, and enhance the sensitivity of hearing and thinking activities.

Scientists have proved through experiments that when the reflectivity of green to light reaches 30%-40%, it can stimulate people's retinal tissue properly, absorb ultraviolet rays harmful to human eyes in the sun, make eye fatigue disappear quickly, and have a bright spirit.

Studies have shown that plants in the forest, such as Chinese fir, pine, eucalyptus, poplar, Sabina vulgaris and oak, can secrete an aromatic monoterpene, sesquiterpene and diterpene gas "bactericide", which can kill diphtheria, typhoid, tuberculosis, dysentery and cholera in the air. According to the survey, there are 4 million germs in the air per cubic meter in dry and forestless places, while there are only 600,000 germs on the boulevard and dozens in the forest.