Hi everyone, just a quick question:

So my young avocado tree has been growing pretty nicely the past two years but now one branch has been growing much faster/thicker on one side, causing my tree to be unbalanced. Now I have it staked so it can stay upright without leaning over too much. My question is how much of that branch can I prune/trim off and when can I do it? I've read early spring, late winter is the appropriate time. Im located in the San Fernando Valley by the way.

Here are some photos

http://imgur.com/KA70IRm,UdJdQlU,haUOy6F,JIPUxrX#0

The branch in question is the one on the left in the first two pictures, towards the top. Thanks!