It’s not just carbon dioxide that feeds a forest. Trees also depend on nitrogen to grow. And the best buffet of nitrogen comes from moss-loving bacteria. But to get a really nutritious growth of bacteria going, the moss needs to age.
Bacteria, called cyanobacteria, that grow on centuries-old tree moss, are twice as effective at fixing nitrogen as the same type of bacteria living in moss on the ground, according to research by Zoë Lindo of McGill University.
That means old-growth trees may be vitally important to the long-term survival of the coastal temperate rainforests that stretch from Southern Alaska to Northern California.