How can a fence made of wood be both a naturally occurring thing and a human-made nonliving thing?

Answer 1

Its materials are natural products that were *once* living.
The fabrication of those materials into planks, posts, and rails requires human action.
The object, a "fence" is a human construct based upon an abstract idea that is realized using materials that, in this case, are naturally occuring and once-living. *Any* fence, in this sense, is man-made and non-living independent of what the materials are: a fence made of wood, petroleum-derived plastic, forged metal, or laser beams is still a fence, and so a human construct.

Answer 2

Wood is naturally occurring because it grows as part of a tree and the wood being turned into a fence post, etc is man-made and non-living

Answer 3

The wood from the fence was once part of a living tree. But when it is cut down and milled it becomes a product and is used to make a fence. It is no longer living but it is not exactly man-made either.

Answer 4

Its living and dead plants.

You could plant trees close together in a line, and put up frames between them, and plant something like ivy to grow and make a living fence.

You could make a wooden picket fence. Thats pretty human made.