Use the children's treasures to create works of art whether it be a collage, mosaic, or a panorama using natural objects.  

Press wildflowers in books. 

Keep a nature treasure box of small rocks, interesting nuts and other found objects.  Children love to handle and sort their own selected treasures.

Think of things you can do with all of the seasonal found objects.  Try making a mobile out of them using sticks and string.  Or see what happens when you put a piece of white cloth or a T-shirt over leaves or flowers and pound on the fabric.  Using paint or an ink pad, use found objects as natural stamps.

Did you see any wildlife during your visit?  Read stories about wildlife creatures and see if your children recognize any from their trip.  Together, see what other facts you can find out about the creature.