Time to just give up and cut this tree down?

I've had this volunteer bird cherry tree for a few years and it's always seemed unhappy and prone to aphids. This year it finally flowered a little bit so I thought it was improving. I'd maybe leave it for the summer and maybe dig it up to try transplanting to a more suitable location for it or giving it away. 

However it's now absolutely covered in what I am assuming are aphids of some kind. It only had a few flowers. Should I just give up on it now and cut it down to put it out of its misery? With all these insects on it should I put the branches in the regular bin instead of the green waste? Are these even aphids?