Photo: Diane Edwardson, January 8, 2010. Several Xmas trees were dumped at the same time on Corralitas Drive near the 2 Freeway. (Click on photo to enlarge.)
Cut up your Xmas tree and put it in the green bin for the City to pick up. They will not pick up the tree if it's sticking out of the bin.
More info: City of LA's Christmas tree recycling program