Vrksasana is the Tree pose, a balancing pose that requires a stable and strong standing leg and openness through the hips. For some, the balancing aspect of this pose is the most challenging. For others, opening the bent leg is too much for the hips, which throws the back out of alignment. There are several pieces to this pose that can be broken down and accessed in different ways, as I've shown in the 6 different variations.
I often advise teachers in my training to think about a pose from different perspectives and relationships to gravity. For example, the image of the pose in the top left corner could be described as side-lying tree and takes the weight bearing out of the pose, but if I continue to align along the outside of the hip of my extended leg, I will discover some balancing challenges.
When we open their minds to these types of adaptations we expand our asana options to offer our students with different abilities or challenges. No one arrives at a yoga class hoping to stay exactly the same after the class as before the class; we all want some level of transformation, but I believe in meeting my students "at the trail head," by which I mean that I establish what they can do before I take them down the path of yoga and offer them something more challenging. This is my approach to asana, meditation, chanting, pranayama and even the language that I use. I do this because I believe that yoga is inclusive.