Why Protecting Old Growth Forests Matters More Than Ever

Old growth forests are among the most magnificent and ecologically valuable ecosystems on Earth. In the Pacific Northwest, old growth forests are defined by their large, ancient trees, complex multi-layered canopy structures, abundant standing dead trees and fallen logs, and rich understory communities of mosses, ferns, and wildflowers. These forests took centuries to develop and cannot be replicated by human management within any meaningful timeframe.

Despite their immense ecological, scientific, and cultural value, old growth forests continue to face threats from logging, development, and climate change. In Oregon, less than 4% of the original old growth forest remains, with the vast majority having been clearcut during the 20th century. Protecting these remaining forests is one of the most important conservation priorities of our time.

The Ecological Importance of Old Growth

Biodiversity Hotspots

Old growth forests support an extraordinary diversity of life. The structural complexity of these forests, with their multiple canopy layers, diverse tree species and ages, abundant dead wood, and deep organic soils, creates a vast array of microhabitats that support thousands of species of plants, animals, fungi, and microorganisms.

Many species are found only in old growth forests. The Northern Spotted Owl requires large trees with complex canopy structures for nesting and foraging. The marbled murrelet, a seabird that nests on mossy branches of old growth trees, has declined dramatically as its nesting habitat has been logged. Red tree voles spend their entire lives in the canopy of old growth Douglas firs, building nests from needles and feeding exclusively on Douglas fir needles. These species cannot survive in young, managed forests.

Carbon Storage Champions

Old growth forests in the Pacific Northwest are among the most carbon-dense ecosystems on the planet. Research has shown that a single acre of old growth Douglas fir forest can store over 400 tons of carbon in its trees, soil, and other organic matter. This is two to four times the carbon stored in a young plantation forest.

Contrary to the long-held belief that old growth forests are carbon-neutral, recent research has demonstrated that these forests continue to accumulate carbon even at great ages. Large, old trees are actually increasing their growth rates over time, adding more wood per year than younger trees. This finding has profound implications for climate policy, as it means that protecting old growth forests is one of the most effective strategies for keeping carbon out of the atmosphere.

Water Quality and Watershed Protection

Old growth forests play a critical role in protecting water quality and regulating water flow. The deep, spongy soils of old growth forests absorb rainfall and snowmelt, releasing it slowly into streams and aquifers throughout the year. This buffering effect reduces flooding during wet periods and maintains stream flow during dry periods, providing reliable clean water for downstream communities and aquatic ecosystems.

The large trees in old growth forests also intercept fog and rain on their canopy surfaces, adding significant amounts of water to the local water budget that would otherwise be lost to evaporation. In coastal forests, this fog drip can account for a substantial portion of total summer water input.

Threats to Old Growth

Ongoing Logging

While the rate of old growth logging has decreased significantly since the Northwest Forest Plan was adopted in 1994, old growth forests on some private and state lands continue to be harvested. In Oregon, private forest landowners are not required to protect old growth trees, and some of the last remaining lowland old growth stands are at risk of being clearcut for their valuable timber.

Climate Change

Rising temperatures and changing precipitation patterns pose growing threats to old growth forests. Drought stress makes old trees more vulnerable to bark beetle attacks and disease. The increase in the frequency and severity of wildfires threatens forests that evolved with low-intensity fire regimes. As climate zones shift northward and upslope, some old growth species may become maladapted to their current locations.

Paradoxically, old growth forests may also be our best defense against climate change. Their massive carbon stores would release catastrophic amounts of carbon dioxide if they were destroyed, while their continued growth helps mitigate climate change by absorbing atmospheric carbon. Protecting old growth forests is therefore both a conservation imperative and a climate strategy.

The Cultural and Spiritual Value of Old Growth

Old growth forests hold deep cultural and spiritual significance for many people. Indigenous peoples of the Pacific Northwest have maintained relationships with these forests for thousands of years, relying on them for food, medicine, building materials, and spiritual sustenance. For many non-Indigenous people as well, old growth forests represent a connection to something ancient, enduring, and larger than ourselves.

The recreational and tourism value of old growth forests is also substantial. Visitors from around the world travel to the Pacific Northwest to experience the grandeur of ancient forests, supporting local economies through tourism spending. This economic benefit is lost when old growth is clearcut.

What Can Be Done

Protecting the remaining old growth forests in Oregon and the Pacific Northwest requires action on multiple fronts:

• Strengthen state regulations to prohibit clearcutting of old growth trees on private lands
• Expand federal protections for old growth on national forests and BLM lands
• Support conservation easements and land acquisitions that permanently protect old growth stands
• Fund research on old growth ecology and the effects of climate change on ancient forests
• Educate the public about the irreplaceable value of old growth forests
• Support Indigenous stewardship of ancestral forestlands

Every acre of old growth forest that is preserved today is a gift to future generations. These forests took centuries to develop and cannot be recreated once they are destroyed. The time to act is now, before the last remnants of these magnificent ecosystems are lost forever.