Question
I want to know how much carbon a tree will take up on average over its lifetime?
I realise this will depend on:
type of tree<
where it grows
how long it lives
But I only need a rough figure (though it would be useful to know each of these points to give it context)
Answers
Sequestration rates will vary depending on species, location (regional and site specific) and the planting and tending regime (if it's a plantation forest), amongst other things.
Sequestration rates change over the life of a tree as well. Eucalypts for example have high upfront seq rates but suffer from earlier senescence (i.e. they decay earlier). Fir trees grow more slowly but have a longer life span, so sequester carbon longer. Many pines fall somewhere in the middle. Again, this varies across sub species and regions.
To answer your question though. A tree that only sequesters 1 tonne doesn't sound healthy enough to last 100 years! A plantation pine tree (like those in North America or New Zealand) might sequester between 700 and 1200 tonnes over a typical 30 year rotation, prior to harvest.
Check out the look up tables published by the New Zealand Ministry of Forestry on growth rates for forests in the NZ ETS: http://www.maf.govt.nz/sustainable-forestry/ets/guide/lookup-table-guide.pdf
Yes you are right that it will depend on those factors. I have seen multiple sources say that a tree absorbs around 1 tonne of CO2 in its lifetime. Thats the rough figure.
I have found this document on how to calculate the amount of CO2 sequestered in a tree in an year. You might find it interesting - http://www.plant-trees.org/resources/Calculating%20CO2%20Sequestration%20by%20Trees.pdf
Here is some other interesting info I found that would give you a better context.
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