When I laid my concrete driveway I used wood to separate the concrete so that in the future I could remove the wood and position proper expansion material. Now I find I can't remove the wood as it is firmly 'stuck' in the joints!! Can I leave the wood in place and will it serve the purpose of an expansion joint. The wood is ordinary cheap pine.
The wood has most certainly taken on more moisture since it has been installed and has swelled into place, locking it in firmly. If you can be patient, and there is a "dry spell" in your local weather patterns, use that time to remove the wood strips.
There will be some concrete bonded to the wood, unless you coated the wood with oil before pouring. To overcome the bit of "grab" the concrete has on the wood, use a block of wood the same width or thickness of the edges and use that as a drive block along with a hammer driving down on the joints to break it loose. Concrete hates vibration. This should allow you to set a 2" screw into the joint and with another block of wood under the prybar or hammer to keep from chipping the concrete, draw the wood out of the joints. That is if the wood has shrunk sufficiently enough. That may take a month of non rainy weather, like a drought season....