im installing concrete pillars to a wooden porch will the concrete adhere to the wood?

No. And, don't remove anything that's currently supporting the porch roof. If they're simply decorative, then you'll need to actually screw them into the wood and preferably the structural framing. They should withstand someone running into them and not just leaning on them.

- FYI, regular porch columns are fully structural and most aren't "attached" at all. Porch columns are normally loaded. Meaning, they're cut long and installed with compression factored-in, they're simply friction-fit. The porch roof usually needs to be jacked-up to properly replace a column.