Forest for the Trees — Kristine Kathryn Rusch

Centuries ago, a tsunami hit the Oregon Coast, destroying miles of coastline. When beach erosion reveals the stumps of a dead forest from that disaster, Anne and Louisa cut school to see the trees. But they freak Louisa out. She sees faces trapped inside the wood -- and she believes she has the magic to free them.

“Rusch builds up the suspense with two believable, clearly different young girls.”
-- Best SF