How about doing something with the "Tie A Yellow Ribbon" song. It is a very popular idea for over here for missing loved ones. Maybe a little acorn under the shadow of an oak tree? How about something from Winnie the Pooh? Doesn't one of the character's live in a tree? Maybe something simple like a fractured oak leaf? Maybe several oak leaves from several species? There are some lovelyneedle point historical pieces with oak leaves and acorns that could be adapted to applique. (look through Coats of Arms?) Hopefully one of these suggestions will spark an idea.