The Tree posture in Yoga is an important posture for the martial artists as it mimics the crane stance.
The important items to remember is that it is a balance posture and should be held for 30+ seconds. Start the posture by raising your leg and placing the foot to the side of the opposite knee. Reach your hands to the sky and look forward. Hold the pose for 30 seconds.
If you fall out of the pose simple reset yourself and try again. You will become more proficient as your work this pose.
WHY IS THIS POSE IMPORTANT FOR MARTIAL ARTS
Often in empty hand Kata work students come across the crane stance. The crane stance should typically be held for at least a half to 1 second within a kata in order to show proficiency in executing the stance. However, far too often students rush through the crane stance and it is barely noticeable. So, it is best to slow yourself down and execute a proper crane stance. Practicing the Tree posture in Yoga will help you to developer stronger muscles so that your Crane stance in your Kata work will look sharp and strong.