According to Feng Shui, people should plant trees around their houses. In ancient Feng Shui books, such a principle is recorded: The east of a house is blue dragon location. There should be flowing water in the location. If there is no water flow, man should plant 9 willows her. The west of a house is white tiger location. There should be wide way in the location. If there is no wide way, man should plant 7 catapal bungeis trees her. The south of a house is rosefinch location. There should be pond in the location. If there is no pond, man should plant 9 cherry baies her. The north of a house is black tortoise location. There should be hill in the location. If there is no hill, man should plant 3 elms her. These trees are Feng Shui trees. It was also a tradition that every village had its own Feng Shui forest. Feng Shui forest lay normally on the entrance of the village. Feng Shui trees and Feng Shui forest must not be damaged. The tradition was weakened in the last century. But now more and more Chinese try to recover the tradition. Some psychologists think that "blue dragon on the left, white tiger on the right, rosefinch in front, and black tortoise on the back" is the most comfortable layout for human. This layout is created based on our memory about our mothers' wombs.
Except the "Blue dragon, white tiger, rosefinch and black tortoise" principle, there are also rules about what and how many plants there should be in the home garden and close to the house. High and big trees are Yang trees, low and soft trees, such as vine, are Yin trees. If most of the trees around the house are Yin, the environment must be Yin. Vice verse. The best environment is Yin Yang balanced. In Feng Shui subject there is much knowledge about adjusting Yin and Yang relationship with Feng Shui trees. On another side, determining the Yin Yang nature of an environment according to the plants around the house, man can make a wise decision when they will buy an house. An Yin environment is harmful to health. The more Yin there is, the more harmful it is. Everyone should have certain Fengshui knowledge and enough Fengshui conciousness to make a good living environment for himself/herself.