|The challenge of the vriksha-asana is maintaining balance on one leg. Poor balance is often the result of a restless mind or distracted attention. Regular practice of this posture will help focus the mind and cultivate concentration (dharana).
When practicing vriksha-asana it may help to imagine or picture a tree in the mind and apply the following technique: Imagine that the foot you are balanced on is the root of the tree and the leg is the trunk. Continue by imagining the head and outstretched arms as the branches and leaves of the tree. You may be unsteady for a while and find the body swaying back and forth, but don't break the concentration. Like a tree bending in the wind and yet remaining upright, the body can maintain balance.
Aim to achieve the "rootedness" and firmness of a tree. Regular practice of the vriksha-asana improves concentration, balance and coordination. Because the weight of the entire body is balanced on one foot, the muscles of that leg are strengthened and toned as well.
As you advance in this posture and are able to remain standing for more than a few moments, try closing the eyes and maintaining your balance.