The Lorn Tree (Arboregal Book 1)
by D.G. Sandru
Four youngsters, Melissa, Perry, Nathan and Michelle materialize in a desolate world where giant, mile-high trees, support all life. They find shelter in the Lorn Tree among the Lorns. Soon after they discover that an evil spirit, Hellferata, wants them dead. Fearful Lorns want to expel the youngsters from their tree, which would be a dead sentence since monsters roam the land at night.