Giant Trees: Mighty Carbon Protectors in Pacific Northwest Forests

Discover how the largest trees play a crucial role in carbon storage and climate change mitigation

By Robert Collins, Environmental Journalist

Recent research in the Frontiers in Forests and Global Change journal has shed light on the significant role that large-diameter trees play in carbon storage within Pacific Northwest forests. Astonishingly, these giants, which constitute a mere 3% of total stems, are responsible for a whopping 42% of total carbon storage in these ecosystems.

Big Trees, Big Impact

Scientists have long known that older, large-diameter trees store disproportionately massive amounts of carbon compared to their smaller counterparts. This recent study supports the idea that preserving these giants is crucial for mitigating climate change.

Protecting the Forest Titans

In 1994, a 21-inch diameter rule was established to protect large, old trees in national forests across the Pacific Northwest. However, proposed amendments threaten to weaken this rule, allowing the harvesting of trees up to 30 inches in diameter. Dr. David Mildrexler, who led the study, emphasizes the vital role these trees play in the forest community:

"Large trees represent a small proportion of trees in the forest, but they play an exceptionally important role in the entire forest community — the many unique functions they provide would take hundreds of years to replace."

A Growing Carbon Storage Solution

The study also revealed that trees over 30 inches in diameter make up only 0.6% of total stems, but account for over 16% of the total aboveground carbon across the forests examined. Dr. Mildrexler explains why allowing large trees to grow larger is essential for climate change mitigation:

"This is why specifically letting large trees grow larger is so important for climate change because it maintains the carbon stores in the trees and accumulates more carbon out of the atmosphere at a very low cost."

Cornerstones of Forest Diversity and Resilience

Large trees not only contribute to carbon storage, but they also support rich ecosystems, act as water towers, and help cool our planet. Dr. Mildrexler suggests that strengthening the 21-inch rule and encouraging local communities to participate in citizen science initiatives can help monitor and protect these forest giants, benefiting both the environment and local economies.

Reference: Mildrexler, D. J., Berner, L. T., Law, B. E., Birdsey, R. A.,