I have a 4-year-old black lab who chews wood occasionally, and she used to love to chew up shoes and would go so far as to pull the insoles out and chew those up too. She'll also pick up sticks or rocks in the yard sometimes and start to chew them, but we handle it by taking whatever it is away immediately and giving her something else as a distraction. We did the same thing with the shoes--if we caught her with one, we told her no and took it away right away and gave her something else, like a ball or a stuffed toy, something that was "approved." I think she eventually associated the balls and toys with being a lot more fun than the shoes and rocks, because the balls could be thrown and bounced and played with and the shoes couldn't.
She doesn't show any interest in shoes anymore, since she has plenty of other toys around. I think if you show a consistent response when she's chewing the wood and give her a more appealing alternative, she may get past it. Bailey still chews sticks sometimes if she's bored, but usually we can get around it by showing her a tennis ball... she's not too attached to wood as a toy, and tennis balls/squeaky balls are her favorite.
We do give her rawhide to chew sometimes, but she tries to chew it too fast and tends to choke, which is scary. Most of the time we give her dental chews, like Greenies, to help with her chewing needs. They're edible and break into smaller pieces than the rawhides do, and she and her sister, Chewy, absolutely love them.

You may not be able to completely rid your dog of her chewing tendencies--she is a lab, after all--but they're smart animals, and they can learn quickly.