Originally posted by VS045
planting a few trees will somehow remove the same volume of CO2 from the atmosphere
Have trees changed since I studied Biology - do they now not remove CO2 and excrete oxygen?
45.
[:D] Thank you for helping illustrate the point - yes, photosynthesis utilises CO2.. but plants also 'breathe' and utilise O2 and releasing CO2. Looking at a tree life-cycle over several years sees much of the 'absorbed' CO2 released back into the air. The proportions are complex to work out, but the concept of a forest being a CO2 absorbing 'machine' is flawed. One of the main factors for this is that there are several rate-limiting steps, such as a limit of nitrogen in the soil.
[Ironically, driving cars which release plenty of nitrogen, ultimately allows trees to absorb a bit more CO2, so there is a vaguely interesting pseudo-argument that driving cars is good for CO2 reduction...

]
Hence the concept of taking a flight, then planting fifty trees, is more about making yourself feel good than any science.