

California gives the federal government way more in tax money than it gets back.
Yes, but
The US needs California way more than California needs the US.
this is not true. California benefits from access to the US dollar. An independent California would either have to come up with its own currency - one that is not artificially inflated by being the world trade currency - or use the dollar at the mercy of the US.
The Amazon, like most tropical rainforests, is poor in potassium and other leachable minerals. Sand from the Sahara brings in new minerals.