Romm on trees and carbon offsets

Here's a great post on Grist by Joseph Romm, author of Hell or High Water, on carbon offsets and trees.

To quote:

Trees are terrific in every way but one: they make lousy carbon offsets. That was the point of the “First rule of carbon offsets.” But a number of comments and some media queries have led me include two rare exceptions: certified urban trees and certified tropical forest preservation. The word “certified” is key in both cases.”