[aukust]

Anecdotal evidence suggests to me that European spruce stores more CO2 than it sheds way over 80 years old as a spruce grows in mass significantly decades after reaching that age.

However here is a study that tries to bring some light to carbon pools on over-mature 167-213 year-old trees: https://www.mdpi.com/1999-4907/9/7/435/pdf

[bryanlarsen]

Anecdotal evidence tells me that spruce trees are really good at suppressing undergrowth due to their acidic needless so claiming a mature first is a net emitter makes sense to me. The trees may be growing, but nothing else is.