Earlier quoted context omitted.
> As these are very large trees, establishing large colonies can have a relatively meaningful impact in carbon capture. Also, they're fast growing, so they capture carbon quickly, and store it for a long time. Plus the fact that, if they're harvested, the wood is relatively rot-resistant. So carbon could be stored over even longer periods, if the wood were used for ~permanent structures. Still, there's something iron…
It might have also been this one: http://www.oregonphotos.com/Sitka-Spruce.html -- it was destroyed by a windstorm in 2007, but I believe it did have such a sign before that. Probably all of the "worlds biggest" trees do.
I sort of remember that it was in Oregon, but doubted myself when I found the one in Washington.