From “The Living Landscape,” Rick Darke and Doug Tallamy:
5 Oak planted today (or not eaten by deer) will sequester 216,000 lbs of carbon dioxide in 55 years, they will sequester 426,000 pounds in 75 years. Older trees are far more effective at this.
The stewardship and sustainability of the Ann Arbor’s entire urban forest needs to be on the radar of the Environmental Commission, then the City for quite some time, via an outreach program.
The City’s Natural Features Master Plan, adopted in 2004, call for exactly that. It should be noted that the typical city property in the US (Ann Arbor does better) uses only 10% of its available land area for tree biomass that they could be.