Here are a few possibilities, though:
* Insects: Many tiny insects like ants, aphids, and mites live in woodlands.
* Spiders: Some tiny spider species like the Jumping Spider are incredibly small and live in woodlands.
* Other Arthropods: Springtails and millipedes come in some very small sizes.
To give you a better answer, I'd need to know what kind of creature you're interested in: insects, mammals, birds, or something else? And are you looking for the smallest by weight, length, or some other measure?