We need to store about 10B tons of C per year if we were to be carbon neutral. We're going to need to build a lot of megastructures out of wood to even keep pace.
Besides, they don't have to be buried that deep. People are still finding intact bodies in bogs in England from thousands of years ago. They're just a few feet down.
In the desert things decay pretty slowly, too. See Sylvester, the cowboy mummy in a museum in Seattle that was found in a sand dune in Arizona with a bullet hole in him.
To start reversing the CO2 emission we would need as many trees it takes to take up the current CO2 emissions and then a bit more.
From what I found you can estimate every m³ (a bit less than 1 American fridge) of Wood stores 1 ton of CO2. Say each hectare of Forest with fast growing trees produces ~ 10m³ per year (more when they are cut down but they need to grow over a decade+. So if they take 10 years that is 100m³ wood yield at the end).
Humanity produced by some estimates 37 billion tons of CO2 in 2020. That means you need 3.7 billion hectare of forest.
The USA has a land area of 157.7 million hectare. So you need an area of 23 times the LAND area of the United States of America just for trees just to HALT CO² at today's level.
How well are fast growing trees growing in the Arizona desert btw?
You're right that trees cannot be 100% of the solution. But they can be a big part of it.
> you think 25 years is enough to store CO2 in?
It's starting to rot at 25 years, lying in the rain and mud and beetles. There are logs much much older than that lying around the local woods. There are stumps over a century old. My house is 25 years old, and the wood structure that has been kept dry has no rot at all. None. Zero. Simply by keeping it dry.
Also I live in a house made from wood, stone, straw and dirt. Depending on how you count its about 400 years old. before that it burned to the ground once. And the Wooden parts aren't actually that old they have been replaced as recently as 100 years ago. the inside has been redone in the 80ies tho and a lot of the wood got taken out.
Its silly to argue for wood as a storage medium even on the basis of that.
Limited to rot resistant trees, such as cedars. Even then, not shielded from the rain for 25 years and not seeing much rot would be amazing.
The ancient Egyptian tombs preserved things very well as long as the tomb stayed dry.
This story sounded so cool, I just looked it up. Unfortunately, the bullet hole is apparently fake and the reason he didn't decay is because an embalmer deliberately mummified him immediately after his death by injecting him with an arsenic-based fluid, which killed off all the bacteria and insects invading the body.