We were at school together <a href=" http://www.ofim-madagascar.com/order-imipramine.pptx#falcon ">tofranil generalized anxiety disorder</a> "Tropical forests are a huge carbon sink. If trees could just grow and store carbon, you could have a rapid sink, but if they don't have enough nitrogen they don't take up carbon," said Hedin, adding that nitrogen-fixing trees are uncommon in temperate forests such as those in most of North America and Europe.