Children are natural collectors, and I'm guilty of the same thing myself, often arriving home with just as much "treasure" in my pockets as my daughter. Rather than discourage our little naturalist-in-training, I carved out some space on an end table to display whatever bounty Claire snags on our nature walks.
We filled a few glass vases with some seed pods and birch trimmings (thank you Amanda, your leftover wedding goodies have been put to good use) and turned a really cool chunk of moss into the centerpiece of our nature table by putting it under glass. A handful of pine cones, some great rocks and 'voila!' a display that looks nice to adults and invites the kiddo over to explore. A magnifying glass is tucked into the pull-out drawer under the shelf and having a lamp on the table already was an added bonus. Our nature table has been in set up since late October and I've yet to see Claire abuse it. Other then stacking the birch trimmings on the floor for towers, everything has been gently examined on the table and returned to its rightful place. Leaves, acorns and the occasional dead bug have made an appearance - if you ask my mother, it's quite an upgrade from housing live millipedes in my cake stand. Study on little scientist, observation is an important part of the scientific method!
I picked up a 9 cubby shelf from Freecycle which is perfectly suited to hold mother nature's treasures, it even has a few pull out drawers with windows. One of these days I'll get around to refinishing it and invite Claire to move the display there. In the meantime this table top approach is working well and it's mighty convenient next to the front door. The one hitch with this setup is the dark wood; the seed pods and pinecones are barely visible against it. See the white placemat under the glass vases? That was my solution, not very pretty but it gets the job done.
A seasonal nature table is a huge part of the Waldorf philosophy so there are lots of nature table ideas out there. Here are two of my very favorite which I think are just beautifully executed:
Sew Liberated has a corner cubby that can be closed from marauding cats and toddlers.
Over at The Write Start, all the natural treasures are labeled with easily changed chalkboards. Great idea, right?