It's just a quote I ran into while doing research. It's from William Wood's New England's Prospect, 1634. He's talking about the deer in New England and how hard they are to catch with dogs.
"In summer it is hard catching of them with the best greyhounds that may be procured because they be swift of foot. Some credible persons have affirmed that they have seen a deer leap threescore feet at little or no forcement; besides, there be so many old trees, rotten stumps, and Indian bars, that a dog cannot well run without being shoulder-shot."
I wonder what the, "Indian bars," are that Woods is talking about? A look in the dictionary shows that, "bars," can mean:
"something that impedes or prevents action or progress. synonym - obstacle"
What's more, Woods is also saying that, "Indian bars," are quite numerous.