Everyone knows that trees absorb carbon monoxide, but how long does the tree need to be alive before someone is able to cut it down and burn it without having ANY negative impact on the environment? (When the tree is burned, is more CO released than was absorbed by the tree?) I was thinking about 10 years to off-set the polution.

Everyone knows that trees absorb carbon monoxide, but how long does the tree need to be alive before someone is able to cut it down and burn it without having ANY negative impact on the environment? (When the tree is burned, is more CO released than was absorbed by the tree?) I was thinking about 10 years to off-set the polution.

For a start it's carbon dioxide (CO2) not carbon monoxide (CO which is a very poisonous gas).

In theory at any point in the life of a tree/plant it has absorbed all the CO2 that would be contained in the plant (barring that released due to respiration).

The way to take the CO2 from the atmosphere is to let the trees grow as the carbon is then contained in the wood/cellulose. Burning them would just release it back into the environment, so what your effectively doing is storing the carbon and releasing it at a later date which isn't actually reducing the overall amount of GG's. Letting the trees grow and not burning them will still mean though at somepoint in the future the CO2 will be released.

And obviously the amount of trees needed to 'offset' pollution depends on various factors (eg climate, type of tree, size, amount of emissions)

That's why fossil fuels have brought down atmospheric levels of CO2 in their formation. The plants absorbed the CO2 and were locked inside the earth, thus bringing down the overall level and changing the atmospheric composition which allowed for an environment that species like humans could evolve to live in.

Then the humans get smart and discover that they can burn that stuff for energy, so they add the carbon right back to the atmosphere.

Would decomposition release it into the atmosphere as well?

Yeah. The only way to not have the carbon released back into the atmosphere is if it is sequestered away through some means like burial.

Obviously, the CO2 released is offset if you plant another tree.

-deus-

Thanks for your input, I did it as extra credit and the teacher raised my grade a full letter. =D