So, I'm building my world, and in the metadata I'm seeing multiple instances of the same tree, some with EP09 or whatever after them. My question is, when building a world, if I want the trees to change seasonally (with the seasons EP), do I need to place specific trees, or will any trees loose their leaves and change with the weather? If I place a base-game oak tree, is that going to look weird when my world is snowy?

I don't think it matters, as a world I built without Seasons works fine with Seasons installed, and all trees lose their leaves just fine.

But test to be sure- you can download this to change seasons:
https://www.modthesims.info/download.php?t=481816

Oh ok, great. Thanks so much! Before I commence placing hundreds of trees in my world, I wanted to make sure I was doing it correctly.