The benefits of vrkasana are many. Your inner thighs, groin and shoulder are all stretchered and strengthened. Your overall posture is also improved when you do this pose on a regular basis. Another great benefit of vrkasana is the calming effect holding the pose has on your mind and central nervous system. As you are developing a deeper sense of balance you are also increasing your mind body awareness.
If you are having difficulty balancing there are options, you can use a wall for support, place a finger on the wall to help stabilize your balance. You also should focus on an area that is not moving in the room to help you maintain steadiness. Another option is placing the toes against the floor to help you maintain your balance. Whatever you do when holding the pose do not place your foot against your knee. Placing the foot hear could cause knee problems and should always bee avoided. Time to practice, develop your balance this week by adding tree pose into your daily practice.