I have been doing this every day, and I can't even tell you how much it helps me.
Breathing is necessary. We breath all day without thinking about it. But once a day I go out into a park or other place with trees and I concentrate on breathing in some of that strength and goodness and breathing out some of my worry and anxiety.
Each time I don't know what I'm going to be breathing in, so I just let it happen and I label it as I feel it.
Sometimes it is the strength of the stones. Or the power of a river. Or the sweetness of flowers. Or the strength and flexibility of the trees. Some times the overwhelming power and enormity of the universe. Each time it is a little bit different.
This is a painting of a feather on a rock.