Even highly biodegradable things (e.g. newspaper) typically don't biodegrade on a human timescale when placed in a landfill. This is mostly because of how dense

Even highly biodegradable things (e.g. newspaper) typically don't biodegrade on a human timescale when placed in a landfill. This is mostly because of how densely packed landfills are, creating an extremely oxygen-deprived environment.