Trees do not grow there now.
Taken from Tree line - Wikipedia, the free encyclopedia
... * Antarctic tree line
The southernmost latitude in the Southern Hemisphere where trees can grow; further south, it is too cold to sustain trees. It is a theoretical concept that does not have any defined location. No trees grow in Antarctica or the sub-antarctic islands. This tree line would be the southernmost point in the environment at which trees can no longer grow, except there are no landmasses that have a true treeline analogous to the arctic treeline.
Trees used to grow there long ago... Discovery Channel :: News :: Antarctic Forests Reveal Ancient Trees