One cold winter day, Danae Schafer and Simon Cain were walking among black spruce trees and tag alder shrubs in Koochiching State Forest in northern Minnesota. As foresters for the Department of Natural Resources, their job that day was to mark the area where trees would be cut down and sold. Simon had recently measured and analyzed trees for this timber sale. In the distance, they saw an evergreen tree that stood out like a giant.

"We noticed this tall, tall tree out in the swamp next to the timber sale area," Schafer said, "so we walked out to it and measured it."

The foresters measured the tree's height, the distance around its trunk, and the spread of its branches, or crown. The coniferous (cone-bearing) tree stood 84 feet tall, had a 52-inch waist (circumference), and spread its branches 18 feet wide. The foresters added up the numbers to see how the size of this black spruce (Picea mariana) compared with the size of other trees of the same species. It turned out to be the biggest black spruce in the state—a Minnesota champion.

Using math, foresters can gain information that helps them care for trees and manage forest lands—choose when and where to plant trees, which ones to cut down, and which ones to leave standing. Whether in a forest, a city park, or your yard, trees produce wood, give wildlife food and shelter, hold soil in place, provide shade, and look beautiful.

This story shows you some ways that you can do math outdoors to learn more about trees. Like a forester, you can calculate a tree's height, volume, and other physical dimensions. And who knows—maybe you'll find a champion.

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