We should ensure that the Tongass National Forest in Alaska remains the world’s largest intact coastal temperate rainforest for the simple reason that this is a place where there are salmon in the trees.

Scientists have found high concentrations of a nitrogen variant — called Nitrogen 15 — in trees near salmon spawning streams. Nitrogen 15 comes from the ocean by way of adult salmon leaving the sea and transporting it in their bodies. Some of the world’s highest densities of grizzly and black bears drag and drop great quantities of salmon from close to 5,000 forest spawning streams to the forest floor. Over time, the nutrients from the salmon decompose into the soil, and the trees absorb them through their roots. Up to 70% of nitrogen in streamside foliage is of ocean origin.

This remarkable ecological phenomenon used to play out all over the Pacific Northwest too. But we broke that connection when we decimated our historical salmon abundance and old-growth forests to a mere 10% of what once was. The Tongass is our last chance to get it right, to show restraint, to show that we can learn to live on Earth without wrecking our home.

Amy Gulick, Clinton