Ludi -
Re Carbon banking, a few points I hope may be of interest.
Some Elephant grasses will sequester more carbon from the air in a summer over a given acreage than some young trees will achieve
(given suitable rainfall, soil temp, etc), but they don't last. Trees of course last 50 to 250 years.
While it's accurate to say that trees will die & release their carbon (as CO2 & CH4)
if they're seen as part of a sustained woodland then younger trees are of course taking in that carbon,
and so maintaining the overall bank.
There is some confusion of terminology between "sink" & "bank."
While woods do 'bank' carbon, it may be released by fire or felling for agriculture.
In the right conditions they will build soil under them which might logically be called a carbon 'sink,'
though it too can be disrupted and made to release its carbon.
That soil building is not automatic though - I understand the Amazon Forest is around 60 MYrs old
and has an average of just one foot of soil under it.
The one carbon destination that is indisputably a 'sink' is on the ocean floor
where vast numbers of the minute cabonate 'shells' of plankton fall and build sediment.
Their carbon is taken from carbon flowing in with rivers and sequestered with wave-splash from the air above.
Your observation of the need for global-scale reforestation effort seems to me spot on -
but it won't be funded, let alone maintained, by taxes (let alone Greenpeace et al).
The best they will manage is little gesture patches -worthy but irrelevant to the scale of planting needed.
If truly widespread reforestation is to be achieved, then it will be productive and profitable to the local community.
Given that energy is the huge new market that forest could supply, location becomes important,
for wood's energy content is only about 55% of that of coal by weight, so haulage has to be minimized.
While the Burlington VT Wood-Fired power stn is exemplary,
our primary shortage will be of household gas and of liquid fuels such as methanol,
both of which can be commercially produced from wood feedstock.
Both of these are far more energy-dense and so more worth transporting than the original fuelwood.
Finally, it's worth noting that sustainable harvesting of fuelwood doesn't remove Coppice-woodland's function as a carbon bank,
and the fuelwood can itself displace fossil fuels' usage under appropriate government.
To clarify this, if a wood is seen as 20 plots felled at one per year and allowed to regrow from the stump,
then after 20 years the first to be felled holds 20 years' growth, the next 19y-g, the next 18y-g, and so on.
In fact the wood holds about 10y-g on average across its area, which is the amount of its sustainable carbon bank.
regards,
Backstop