Extension 17.7: Planting Trees

Energy, Ch. 17, extension 7 Planting trees 10
Africa. F. Myers (760) of the World Wildlife Fund instead used tropical pines and
eucalyptus to estimate a net fixation of 10 tonnes of carbon per hectare per year. Thus,
foresting of 465 to 670 Mha, compared to a current forest area of 3.4 Gha, would be
required to sequester the 5 Gt/yr released by fossil fuel burning. (40) Marland and
coworkers at the New Zealand Forest Research Institute found that Pinus radiata that is
harvested and replanted socked away 112 tonnes of carbon per hectare over the course of
the lifetime of the trees. (761)
A recent estimate of the one-time cost of planting enough trees to absorb 2 to 3 Gt of
carbon per year is $186 to $372 billion. (762) It would cost $230 to $1,000 per hectare for
planting plus land cost of $400-$1,000 per hectare. (762) The estimated cost is $2.2/t of
carbon removed. (40) This cost should be compared to the cost of doing nothing. A sea
level rise could cause $300 million in land loss alone. A recent estimate by the EPA of the
total cost of protecting against a 1 m rise in sea level would be $73 to $110 billion. (496) Of
course, not all the CO 2
would have to be compensated. It would be possible, for example,
to forest 300 Mha for $120 billion and achieve a 26% CO 2
reduction. (763)
One study of vegetative storage asserts that “[t]emporary carbon stores would only be
beneficial for climate change impacts related to the cumulative impact of CO 2
, but it could
even worsen impacts mediated via the instantaneous effect of temperature or those related
to the rate of change. Hence, the planting of trees is only beneficial in reducing climatechange
impacts if the most serious impacts are those related to the cumulative effect of
increased temperature.” (764)
Costs are expected to range between $10 and $150 per tonne and worldwide up to 2
Gt/yr could be stored at this price, but secondary benefits occur as well that can reduce
the final cost—if these are high enough, forest storage of CO 2
may be a “no regrets”