by Michael Smith (Veshengro)
A single tree, it is reckoned, will absorb one ton of carbon dioxide over its lifetime and the shade provided by trees around a home can also reduce your air conditioning bill by ten to fifteen per cent.
While this is true we have to remember, however, what lifetime and absorption here means.
Only while the tree actually is of a good age will it absorb carbon. After a certain age a tree, actually, becomes a carbon producer and a methane producer too. Namely when it begins to decay on the inside, after its true productive life.
It is for that reason that trees are felled by proper foresters just before that time. Coppicing, on the other hand, makes for trees that are continually absorbing carbon.
Thus simply saying that a single tree will absorb one ton of carbon dioxide over its lifetime is misleading to some extent for one has to remember that not every tree has the same operational lifespan and some live longer than others.
Conifers, such as pine and spruce, have an active life of about forty years after which they begin to die off from the inside and thus becoming a producer of the decay gas methane. At the same time the amount of foliage is being reduced reducing the efficiency of carbon sequestration and not long after the tree will, in fact, become a net carbon producer.
Deciduous trees, aka broadleaved trees, have a longer active life but again it depends on the species. An oak has about eighty to a hundred years maximum before it becomes a carbon producer, other broadleaved trees have a shorter span, birch being one of the lowest.
While a tree is growing it, actually, absorbs more carbon than when it has come to the final stages of its life and thus making use of the trees and then either replanting or encouraging natural regrowth, as in the finest woodland management system known to man, coppicing, will ensure continuous carbon sequestration.
Alas, this factor is something that the “we must not cut down any trees” brigade does not like to talk about and no, Nature does not regulate it itself. Not in woodlands that have been managed before at least.
Leaving woodlands unmanaged creates death and not new life, regardless of what some in the environmental movement like to believe, and therefore the simple statement of “a single tree will absorb one ton of carbon dioxide over its lifetime” is rather misleading to the uninitiated.
Foresters, even and especially commercial foresters, are not the enemy of the woodlands and the trees; they are their custodians. They are farmers who plant a crop but will never, in general, harvest this crop. They create for a future that they will never see. They have been doing it for centuries.
Britain was once an island of trees and our woodlands have been managed by coppicing for several thousands of years by now and they have served us well.
The charcoal produced in British coppice woods was what fuelled the industrial revolution and not until the arrival of coal and oil did that change.
The furnaces and the smithies of the country were fuelled by British charcoal from British woods (predominately). Other industries too used the resources of those well managed woods and wood and wood products were everywhere. But that is a story for another time.
© 2013
