Anyone know what type of fruit tree this is? Thank you.

I suspect that is a Mulberry seedling - likely Morus alba.

That's a big pest plant in most of the eastern US, but I'm not sure how it behaves in California.

I agree with Mulberry.

Sure looks like one.

It is illegal to plant them in New Mexico because of pollen output. Btw, they grow really fast.

Thanks for confirming. I suspected it was mulberry. Must have grown from seeds dropped by a bird from a neighbors tree. I will probably dig it out and plant it in a container.