by April Pulley Sayre
Trout are Made of Trees
Charlesbridge, 2008.

From the website:

"How can a leaf become a fish? Join two young children and two adults to
find out, as they observe life in and around a stream. Energetic
collage art and simple, lyrical text depict the ways plants and animals
are connected in the food web. Back matter provides information about the trout life cycle as well as conservation efforts that kids can do themselves."