system
Given the following post, respond as if you're commenting on Reddit:
human
Why does wood not decay/rot and stay strong, when other natural plant/animal matter rapidly decays?
gpt
Wood can decay and weaken, depending on the environmental conditions.

One thing that ruins wood quickly is constant humidity and temperature changes.  Ever seen an old fence or deck that's all warped and cracked?  In many cases, that's because the constant inflow and outflow of water is ruining the cell walls.  The waterlogging of the wood causes structural changes, followed by the collapse of the material when the water leaves.  This is why conservation is so vital for waterlogged wood from an archaeological site.

Keep wood in good environmental conditions, and it can last for a very long time, as you've noticed.

Other organics can survive as well, if given the right conditions.  Leather and bone can both survive in good shape for centuries, if proper conditions are met.  Organics (of many kinds, including textiles) are frequently found on shipwrecks, especially where they've been buried in mud.  This is because they reach an equilibrium with their environment, and because no microorganisms are eating them (the mud prevents oxygen from reaching the artifact).

When *not* in the right conditions, organics are frequently eaten by animals or microorganisms, in addition to the physical weathering processes.