Letter from the CEO

Aspen trees, like these found in the Roaring Fork Watershed, are clonal organisms and among the oldest know living organisms.

Protecting forests made of ancient and new carbon

Hyperion, a coastal redwood in California, is considered the world’s tallest tree at 380 feet high. The General Sherman, a giant sequoia in California, is the world’s largest tree in volume, at 36 feet in diameter, 275 feet tall, and with an estimated 52,000 cubic feet of volume. Árbol del Tule, a cypress in Oaxaca, Mexico, is the world’s stoutest tree at 46 feet in diameter. ACES’ own Hallam Lake preserve includes Colorado’s largest narrowleaf cottonwood tree.

But more interesting than size is the age of trees. Methuselah, a bristlecone pine in California, is 4,789 years old. Woolly mammoths walked the earth when this tree was born, nearly 2,800 years before Jesus! Pando, an aspen stand in Utah, is the oldest of clonal trees with roots estimated to be 14,000 to 80,000 years old. That’s before the invention of agriculture, in the middle of the last ice age, and before the first humans inhabited North America.

But the most important story of trees relates to their role with the carbon they hold. That story begins with the origin of all trees.

Nobel Prize–winning physicist Richard Feynman once posed a seemingly simple question: Where do trees come from? We think of trees as coming from the earth—roots firmly planted in the ground. But Feynman pointed out that this isn’t exactly true. Trees come from the air.

And it’s this simple fact that has put modern society on the brink of ecological disaster! To understand why, we must go back millions of years to the rise of Earth’s first forests.

Billions of years ago, Earth’s surface was too hot for plant and animal life. Our planet’s atmosphere was a dense blanket of carbon dioxide, similar in composition to that of Venus. Solar rays would pass through and become trapped, creating the ultimate greenhouse effect. Over time, cyanobacteria began to remove carbon and release oxygen into the atmosphere as a result of photosynthesis, eventually tempering the climate enough for the first plants to evolve.

About 500 million years ago, these plants were no more than ankle high. To further colonize Earth’s surface, plants needed to evolve structures to allow them to grow taller to compete vertically for sunlight.

Almost 400 million years ago, the evolution of complex plants would forever alter the nature of our planet. With vertical plant communities, the world’s first forests, springing up in response to increased access to sunlight, ushered in an unmatched era of growth on our planet, called the Carboniferous Period.

Plants began to produce lignin, strong yet flexible polymers, primarily composed of carbon, that allowed plants to grow taller. These polymers were, essentially, the precursors of wood. These tall, fern-like plants were the first to exhibit tree-like structures. This was a game changer!

Through photosynthesis, these first forests pulled massive amounts of carbon from the atmosphere, replacing it with oxygen, a plant’s waste product. So, Richard Feynman was right! Question: Where do trees come from? Answer: Carbon from air.

At the height of this period, 300 million years ago, habitat creation by our first forests paved the way for animal life on land to flourish as well.

However, this change happened so fast that other ecosystem services couldn’t keep up. The plant decomposers of the time (fungus and bacteria) hadn’t yet evolved to process lignin. So, when these early trees died, instead of decomposing, they piled up and were buried in the mud for millions of years.

That layer of organic matter buried during the Carboniferous Period (359 to 299 million years ago), “ancient carbon,” became the coal and oil that we burn today. Humans are now reversing the work that our first forests did millions of years ago to make our planet a habitable place by releasing that carbon back into the atmosphere at unprecedented rates.

In addition to releasing “ancient carbon” stored by trees hundreds of millions of years ago, humans are rapidly depleting the “new carbon” stored by today’s forests. Earth’s forest ecosystems hold more carbon than is in the atmosphere. By clearing native forests for development and agriculture, humans are releasing this carbon, which is responsible for 35 percent of all greenhouse gases. Combined with the release of “ancient carbon,” the carbon cycle is drastically out of balance, resulting in the climate change we face today.

ACES’ Forest and Climate division is working to address this through public education and on-the-ground forest health restoration. Whether it be through our Forest Health Index (an educational tool used in schools), our Know Your Trees guidebook, conducting prescribed burns (with our partners), or managing beetle infestation with pheromone treatments, ACES is working to create resiliency in our regional forests while getting the word out on the issues facing forests beyond Aspen.

Finding creative ways to keep the “new carbon” in our forests and the “ancient carbon” in the ground is our challenge. This report shares our efforts. I hope you’ll join our movement.