The nitrogen cycle requires bears. Brown bears catch salmon in streams and rivers. Then the brown bears carry the salmon farther inland, and they bury these nitrogen-rich fish in the ground for later retrieval. But bears have short memories, and often they forget the fish where they left them, far inland from the streams. And the fish bodies decompose, leaving a reservoir of nitrogen in the ground. This creates a rich and fertile environment for large trees to grow, and in fact
