I am a little late on this news, but since it is going to take 13 years to finalize, I don't feel so bad.
Last Saturday, Mayor Menino announced that the city of Boston is going to recieve 100,000 more street trees over the next 13 years.
"As part of the initiative, the mayor will also announce a new partnership with the US Forest Service that designates Boston as an urban experimental forest -- one of three such sites in the country -- where scientists and arborists will conduct research to document the effects of trees on people and the environment."
- Jenna Russell on Boston.com
One of the reasons for this intiative, along with cooler temperatures and cleaner air is, improved psychological affects urban trees have on humans. They are even investigating to see if increasing street trees decreases crime rates. wow.
The article also featured a pretty awesome breakdown of trees in specific areas of Boston: