[Sally Le Page (OP)]

Granville wants to know:

"If 1-2 fully grown trees are enough to sequester one's CO₂ for one year, according to calculations of biomass, why is the tree not enough for the future years? Why do you need to plant a new tree every year for life? It is not like the tree looses its ability to change CO₂ as it ages."

Any ideas?

[alancalverd]

Trees do not grow indefinitely large, and most do not live for ever. And there's a  lot you can do with a healthy adult tree, like turn it in to houses and paper, so it makes economic and ecological sense to keep planting young ones and cut down the old ones.