LI Shuhua, YAO Yanan, LIU Chang, KANG Ning

Green space refers to the land covered by plants, and the effect of green space on human health is profound and extensive.In recent years, a series of comprehensive studies on green space health function have emerged in China.Consequently, the purpose of this paper is to systematically sort out the specific effect and mechanism of green space on human health, and on this basis, to put forward the proposal of green medicine.

1 The Effect of Green Space on Human Health

Green space is beneficial to human health, which has extensive empirical support.It is proved by domestic and foreign researches that people's selfreported health is better as living in a high-quality green space.It involves physical health, psychological health, and social health.

2 The Mechanism of Green Space to Benefit Health

2.1 Approaching nature is the most basic attribute of human beings

After more than a million years of human evolution, many responses of humans to the natural environment have developed based on the genetic evolution, including feelings, cognition, and behavior.Thus, being in the green space with plants as the main elements can satisfy the basic demands of people to return to nature.In the study of human environmental preferences, various hypotheses have been incorporated into the "biological hypothesis".These theories have also been utilized in the practice of architectural and environmental design.

2.2 Improving the conditions of living environment

Natural elements in green space, especially plants, can improve environmental conditions and provide ecological products that are beneficial to people's health.Also, it can improve thermal comfortability and reducing noise.

2.3 Stimulating five senses

Sky, sunlight, plants, water and the other landscape elements in the green space can bring rich sensory stimulation.The eyes, ears, nose, skin and tongue can feel and receive environmental information.Then the nervous system produces a comprehensive impression in the human brain.

2.4 Providing supportive space for physical activities

Moderate amount of physical activities is an important foundation for maintaining health.Green space is an important place for outdoor activities, which provides venue support for various activities.

2.5 Inspiring association

Contacting with green space and feeling the vigorous vitality of plants can inspire people's yearning and love for nature.Feeling the connection with other life and the cultural meaning of plants can make people have rich association."Mind wandering" and "meditation" are often forgotten by modern people, but are very high-level and healthy spiritual experiences.

2.6 Tree energy and aura

Plants are the source of energy.Many places in the world have "Tree Qigong Therapy".Of course, the energy and aura of trees and their utilization in horticultural therapy, forest therapy and other aspects need to be further studied and verified.

Tab.1 Comparison of Western Medicine, Traditional Chinese Medicine and Green Medicine

3 Green Medicine Proposal

Through the above research on the health efficacy and mechanism of green space, as an auxiliary medical means of modern medicine (Western medicine) and traditional Chinese medicine, here we will call the method, which uses green space as the medium and can cure chronic diseases, mental diseases and disorders and prevent the diseases in the future, as green medicine, and put forward the following proposals for it (Table 1).

3.1 A Proposal of green medicine

1) Perspective of green medicine.

Unlike white medicine (Western medicine), green medicine must have a diversified perspective, a holistic perspective and an ecological perspective.

2) Service object of green medicine.

The service objects of green medicine are mainly those suffer from senile diseases, chronic diseases, mental and psychological diseases, sub-healthy people and rehabilitation diseases.Besides, green medicine is effective in maintaining physical and mental health of healthy people and preventing diseases.

3) Green prescription.

For the above target of green medicine service, green prescription is to go out into the nature.Similarly, during the implementation of horticultural therapy, different plant species and horticultural operation contents should be selected according to the physical conditions of different participants.The plants, the operation and the walking routes selected for the patients and participants in the green space are green prescriptions.

3.2 Constructing green space from the perspective of human health

In order to give full play to the health and hygienic effect of green space, we must consider the functions, the service object, the selection of plant species, the design methods and the maintenance and management of green space carefully.Meanwhile, it is necessary to formulate utilization procedures and plans according to the physical and mental health characteristics of service objects.In addition, when using therapeutic green space, special guidance professionals would be necessary, such as forest therapists, horticultural therapists and so on.