The Problem with Trees as a means of reducing Carbon Dioxide levels.
Trees are regarded as part of the ‘lungs of the planet’
Trees appear to be a natural simple solution to reduce the effects of Global warming.
A recent study carried out at Kielder Forest has calculated that the Forest’s 150 million trees lock up 82,000 tonnes of carbon* annually. This means that as a rough estimate each tree at Kielder is locking up 0.546 kg of carbon per year – equivalent to 2 kg of carbon dioxide.
Source: http://www.forestry.gov.uk/pdf/6_planting_more_trees.pdf/$file/6_planting_more_trees.pdf
But just how many trees would be needed to absorb the human introduced Carbon Dioxide in the Atmosphere. ?
Applying the relation of Carbon to Carbon Dioxide.
1 Gt of carbon = 3.67 Gt of CO2
1ppmv of CO2 = 2.13 Gt Carbon
1ppmv = 7.81 Gt of CO2
Natural Atmosphere levels.
The natural atmosphere sink level of Carbon = 720 Gt Carbon
The natural atmosphere sink level of CO2 = 2642 Gt of CO2
The natural atmosphere sink level of CO2 in ppmv
720 Gt Carbon x 3.67 = 2624 Gt CO2 / 7.81 = 338 ppmv of CO2
Human Additions.
If all of the fossil fuel reserves of the planet were burnt
humans would add to the natural atmosphere sink of CO2
by 768ppmv - 338ppmv = 430ppmv CO2 = 916 Gt of CO2
= 250 Gt of Carbon
Applying the Kielder amount of Carbon and CO2 absorbed by a tree.
15,000,000 trees in Kielder Forest would absorb = 82,000,000 kg of carbon
1 tree locks up 0.546 kg of carbon / year
This equates to 3.67 x 0.546 kg = 2 kg of CO2 per year
= 0.000000000002 GtCO2 / year
Scenario 1 – Plant enough Trees to reduce CO2 levels into the Atmosphere.
This needs 916 Gt CO2 / 0.000000000002 Gt CO2 = 458,000,000,000,000 trees
This allows for every person on the planet. = 65,428 trees
Allow 2500 trees per hectare as at Kielder Forest
Planting these trees would require = 183,200,000,000 hectares
Source: http://www.forestry.gov.uk/forestry/infd-6xjf34
This will require about 60,000 times the area of the total woodland in Britain in 2011.
Source: A report to mark the International Year of Forests 2011 Woodland Trust
Allow for planting trees at a rate of 750 hectares / year = 244,266,666 years
Source: http://www.forestry.gov.uk/forestry/infd-6xjf34
Allow for 5 years growth per tree = 1,221,333,330 tree years
Allow £100 / tree = £45,800,000,000,000,000
Conclusion
This indicates a slow atmospheric CO2 to carbon absorption and conversion by the trees in one year.
It also indicates a very large number of trees will be needed.
It indicates a large area of land will be needed.
It indicates a planting time programme that is unfeasible.
It indicates that the growth rate per tree will not allow for harvesting and secondary use of the forests being planted. This is a waste in resources.
There will also be a large number of people, greenhouses and nursery facilities to propagate the seedlings, care for the mature trees and to farm them for timber.
It indicates a cost for the work that is unfeasible.
If only the atmospheric absorption is allowed for then tree planting does not seem to be viable. However allowing for the atmosphere as a percentage of total carbon sinks can reduce the Gt that the atmosphere will need to deal with reduces the total Gt load.
Scenario 2 – Plant enough Trees to reduce CO2 levels into the Atmosphere but allowing for absorption through the other planetary carbon sinks.
Total Earth carbon sink potential = 75,127,382 Gt Carbon
Total atmosphere carbon sink = 720 Gt Carbon
= 0.0009 % of total Carbon sinks
Of the 916 Gt of CO2 0.0009 % would be absorbed
by the atmosphere = 0.008244 Gt CO2
This allows for 0.008244 Gt / 0.000000000002 = 4,122,000,000 trees
Allow 2500 trees per hectare as at Kielder Forest
Planting these trees would require = 1,648,800 hectares of land
Source: http://www.forestry.gov.uk/forestry/infd-6xjf34
This will require about half the area of the total woodland in Britain in 2011
Source: A report to mark the International Year of Forests 2011 Woodland Trust
Allow for planting trees at a rate of 750 hectares / year = 2,198 years
Source: http://www.forestry.gov.uk/forestry/infd-6xjf34
Allow for 5 years growth per tree = 10,992 tree years
Allow £100 / tree = £412,200,000,000
Conclusion
This indicates the same slow atmospheric CO2 to carbon absorption and conversion by the trees in one year.
It indicates a very large number of trees will be needed.
It indicates a large area of land will be needed.
It indicates a planting time programme that is unfeasible.
It indicates that the growth rate per tree will not allow for harvesting and secondary use of the forests being planted. This is a waste in resources.
There will also be a large number of people, greenhouses and nursery facilities to propagate the seedlings, care for the mature trees and to farm them for timber.
It indicates a cost for the work that is unfeasible.
End Summary
Planting trees to solve the increase in global climate temperatures caused by natural and then human fossil fuel emissions is not currently a viable solution.
Ian K Whittaker
Websites:
https://sites.google.com/site/architecturearticles
Email: iankwhittaker@gmail.com
09/09/2013
14/10/2020
887 words over 2 pages