Why do trees stems grow new "parts" inside and not outside i.e. why is the oldest part of the stem the innermost "ring" and not the outermost?

Wouldn't grow something from the inside require a very strong force to "move" the already present one? Instead growing from the last "layer" towards the outside would require a lot less force, but perhaps a lot more matter.

Is it even correct that trees grow concentrically?

Now that I think about it, how do plants grow in general? Hahaha

Update: for everyone wondering, yes, my question doesn't make sense because the i.e. contradicts the question. I don't want to correct it because I don't know which part to correct since I was wrong, I thought trees grew new parts inside and pushed older parts outside. So I could correct the i.e. and swap "innemost" with "outermost" but that would mean that people would read a question stating something that is wrong, or I could correct the question and swap "inside" with "outside" but I was wrong and I'm glad I learnt something today. We can all agree that I asked a weird question in a weird way, thank you all for your answers.