Cactus Tree?

I found this odd "plant" in my new Los Angeles Neighborhood (Mar Vista) and I had to stop to talk a photo. This might be a variety of cactus that I am not aware of, but to me it looked like a tree (perhaps a birch) grew simultaneously with/outside of a cactus?

In hind sight I wish I had gone across the street to get a full picture of this behemoth of a tree. The top was full on cactus and the bottom looked like a tree stump. I love this mix of textures. Here are some close ups of the texture.