Part 2: You didn't say, but should have said, that you are reading "The Yearling," a 1938 bestseller by Marjorie Kinnan Rawlings, that is set in the "Big Scrub" area of 1870s Florida. Part of its interest to U.S. readers is that it is about a time and place in the U.S. that most of us know little about.
It is FULL of vocabulary, phrases, and colloquialisms that most native English speakers do not know.
I don't know what a bay-head is, I have to guess from context. This is probably what most native English-speakers need to do.
The "head of a bay" is the most inland part. The setting of "The Yearling" is near Cross Creek and Silver Bay Springs, names I didn't know until I found
http://www.npr.org/2011/07/21/138561573/on-location-the-central-florida-of-the-yearling . Now I come from the New England area and think of a "bay" in terms of water, but it seems perfectly clear that in this context, it means the densely overgrown land NEAR the head of the bay--territory that would require constant work pushing through close-grown shrubs.
Fortunately I have a searchable PDF of "The Yearling" so I can check for other places where the word is used and in another place I find: "The deer were feeding on the tender growth, bud of sweet bay and of myrtle, sprigs of wire-grass, tips of arrowroot in the ponds and prairies, and succulent lily stems and pads. The type of food kept them in the low, wet places, the swamps, the prairies and the bay-heads."
So a bay-head is a kind of low, wet land, that grows the kinds of shrubs deer like to eat.