With tea tree braids or simply tree braids hair is cornrowed using extensions.
As the corn row continues, more and more hair is added but bits of the hair extension are left protruding. Once the braid extends just past where your hair ends, a knot is tied to stop the braid from unravelling.
This is an awesome protective style that doesn't add too much pressure to hair. watch the video at the bottom to understand how they work better.
Crochet braids are more similar to weaves than to braids. With crochet braids a crochet needle is used so sew braids / curly hair extensions into hair that has been corn rowed.
How long do they take to put in?
4 hours or less. They should take less time than tea tree braids but I personally think tree braids would last longer and better.