If we are picking nits, most of the wood in living trees is not alive.
A decade is not a very long period of time in the context of the climate system.
You are being deliberately obtuse.
If a decade (and I didn't say a decade) is not a very long time in the context of the climate system, then how come there are measurable and visible changes in the climate during last decades?
How come there are visible and measurable changes in the ozone layer - for the better?
We typically define climate via the long-term average, about 30 years, to filter out short-tern random fluctuations, but also cycles like the 11/22 year sunspot cycle. The Montreal Protocol on Substances that Deplete the Ozone Layer was signed 1987, nearly exactly 30 years ago. 1996, 20 years ago, emission of controlled substances was not to exceed zero. And we can now tentatively detect the fist signs of a slow recovery of the ozone layer. And that is for a very simple, direct process that only involves the atmosphere, with few feedbacks.
Besides - I was talking of wood being explicitly left to the elements and the ecosystem to reclaim it. I.e. Left to "rot".
On the other hand, while "decades and decades" which may take a piece of wood to rot naturally and decompose back to carbon (which basically never happens as it gets used up by the ecosystem centuries before that can happen) - a bullshit time period or physical state like "permanently" doesn't even exist.
No, wood does of course not decay to "carbon". It mostly gets consumed by other organisms, which use it to produce energy, resulting in, surprise, CO2, either directly or via the route of methane, also a greenhouse gas, and one that relatively quickly decays into CO2 in the atmosphere, thus completing one particular path through the Carbon cycle.
Much of the carbon in the coal we now dig up has been sequestered during the Carboniferous, over a period of 60 million years, ending 290 million years ago. It has thus been sequestered for a around 300 million years. Carbon in most crude oil reservoirs has been sequestered for 100 million years or more. On human and civilisation time scales, that is essentially forever. A few decades is not forever.
If it did - we wouldn't be able to use fossil fuels in the first place. Carbon would have been "permanently sequestered".
Also, you should really go to a museum.
Primarily to look up how long have we actually had museums AND ways to preserve stuff in them.
Then look up all the wooden artifacts found. All they needed to stay preserved for millennia was a thin layer of dirt or water to keep all those aerobic bacteria out.
Hell, we got processed wood from over 4000 years ago.
And yet, the number of wooden artefacts from the past is so low that we actually do put them in a museum to preserve them. Nearly all of them have decomposed, one way or the other, over time. One poster above cited an estimate of 3 trillion living trees, or 375 trees per human. Older estimates are around 400 billion, or 50 trees per human in the ecosphere. How much wooden artefacts does the average human have? I'd be surprised if my furniture makes up one decent-sized tree. The amount of wood in artefacts that are preserved (usually for a small while) is miniscule. We have no ancient triere, although Herodotus tells us there were hundreds built under Themistocles alone. We do have HMS Victory, but none of the hundreds of her contemporary ships of the line.
Sequestering carbon is a piece of cake. Literally. We make cakes out of sequestered carbon.
It's only sequestered if you neither eat the cake, nor allow it to be eaten or to decay otherwise. Otherwise its still part of one of the short-term carbon cycles (plants use photosynthesis to fix carbon from CO2 into complex sugars, animals and bacteria consume these sugars, using the stored energy, and turn them back into CO2).
If we wanted to, we could sequester it all into the ground. We don't want to. Nor do we need to.
We're keeping it sequestered in mobile form. As humans and food for humans. And you need to grab a lot of carbon from the air to feed 7.4 billion humans (and growing) and all our pets and food.
Unless total biomass is increasing, that is not removing CO2 from the atmosphere. Once Waldo dies, it decomposes and releases the carbon from its complex structure back into CO2.
And when we're done with using our carbon we put it under ground. Or we reclaim it and use it to trap more carbon.
Or we put it in a large pile and cover it with more stuff until no air can get to it. Just like we always did.
We know, beyond any reasonable doubt, that neither we nor the environment are sequestering carbon at a rate remotely sufficient to compensate for the fossil carbon we release into the atmosphere. We know that from the simple fact that we can measure atmospheric CO2 (and its isotopic composition), and it goes up by about 2ppm per year at the moment, from sources that matches the isotopic composition of our fossil fuels. We also know that a lot of the CO2 that is removed from the atmosphere goes not into permanent sequestration, much less into human artefacts (if intentional of not), but is absorbed by the oceans, forming carbonic acid and causing a measurable decrease in ph level.