Using Fractals to Mitigate Climate Change

NOVA: Hunting the Hidden Dimension

Paso Pacifico founder, ecologist Sarah Otterstrom,
ponders our carbon sequestration projects. 

Bill Enquist, a plant ecologist at the University of Arizona, is using fractals to further understanding of forests and how they remove carbon dioxide from the atmosphere to help regulating the Earth's climate. Enquist and his team of scientists are working in forest reserves in the Guanacaste Province in Costa Rica, which borders the area where we work in Rivas, Nicaragua. Their explorations of trees and forests is fascinating, and has a lot of implications for our Return to Forest project to mitigate climate change a few miles north.

BRIAN ENQUIST: If you look at the xforest, it, basically, breathes. And if we understand the total amount of carbon dioxide that's coming into these trees within this forest, we can then better understand how this forest then, ultimately, regulates the total amount of carbon dioxide in our atmosphere.
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CHRISTINA LAMANNA (Santa Fe Institute): So, if we know the amount of carbon dioxide that one leaf is able to take in, then, hopefully, using the fractal branching rule, we can know how much carbon dioxide the entire tree is taking in
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BRIAN ENQUIST: We're going to census this forest. We're going to be measuring the diameter at the base of the trees, ranging all the way from the largest trees down to the smallest trees. And in that way we can then sample the distribution of sizes within the forest.
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NARRATOR: Even though the forest may appear random and chaotic, the team believes it actually has a structure, one that, amazingly, is almost identical to the fractal structure of the tree they have just cut down.

JAMES BROWN: The beautiful thing is that the distribution of the sizes of individual trees in the forest appears to exactly match the distribution of the sizes of individual branches within a single tree.
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BRIAN ENQUIST: By analyzing the fractal patterns within the forest, that then enables us to do something that we haven't really been able to do before: have, then, a mathematical basis to then predict how the forest as a whole takes in carbon dioxide. And ultimately, that's important for understanding what may happen with global climate change.
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NARRATOR: For generations, scientists believed that the wildness of nature could not be defined by mathematics. But fractal geometry is leading to a whole new understanding, revealing an underlying order governed by simple mathematical rules.

GEOFFREY WEST: What I thought of in my hikes through forests, that, you know, it's just a bunch of trees of different sizes, big ones here, small ones there, looking like it's sort of some arbitrary chaotic mess, actually has an extraordinary structure.

NARRATOR:  A structure that can be mapped out and measured using fractal geometry.

BRIAN ENQUIST:  What's absolutely amazing is that you can translate what you see in the natural world in the language of mathematics. And I can't think of anything more beautiful than that.

Read the full transcript or order the DVD on the NOVA website at PBS.org.