Everything you need to understand or teach The Ancient One by T. A. Barron.
The Ancient One combines science fiction, fantasy, and myth with environmental activism and adventure to tell the story of Kate Gordon's summer visit to her great aunt Melanie in Blade, Oregon. Soon after she arrives for a summer visit, Kate and her great aunt become embroiled in a battle with unscrupulous and unemployed loggers to save an old growth redwood forest that is also a sacred place to a Native American tribe, the Halamis. While walking in the forest with her great aunt's owl-handled walking stick, Kate is mysteriously transported back 500 years through a time tunnel where she then becomes involved in a mighty struggle between the forces of good and evil for control of the land—a struggle which mirrors the environmental conflicts of her twentieth-century world. In the world of the past, Kate encounters a lush natural environment that is threatened by the Wicked One...