This is what happens when wood siding is too close to the ground.
It gets wet, it rots, and it attracts termites!
Wood siding should be 4" or so from the ground whether that be soil or solid surface. Six inches would not be too far.
The further the better. When it is higher from the ground splashing water onto the wood is minimized.
The wood is not sitting in a moist or wet condition, so it is not wicking moisture.
And termites are less inclined to try to reach it with their mud tunnels.
But if wood siding is too close, even siding that has been primed and painted, it is an invitation to trouble!
And the siding in this photo is a buffet!
Microbial growth requires three things - air, food and water. Of course temperatures play a role, but water is the catalyst!
Termites are looking for wood to eat, preferably moist wood. And termites work as a team 24/7/365. A single colony of termites can contain billions, and they come and go, stopping at the Valhalla feast to munch down and return to the queen.
What termites were created to do they do very, very well.
My recommendation: insure that wood siding is better protected by making sure it is at least 4" from soil and moisture. Keep it painted or stained. Fill holes and gaps and cracks with caulking when they occur. Maintenance goes a long way toward the longevity of anything. Fall is the perfect time for such maintenance, before it gets too cold.