Discover the climate benefits of old-growth forests vs. reforestation. Which strategy is more effective in carbon sequestration and biodiversity conservation? Read more to explore the best approach for climate action.

Written by Warrence Oghenevwegba

Published on: March 11, 2025, 10:36 P.M

Old-Growth Forests vs. Reforestation: Which Matters More for Climate Action?

Forests have long been our planet’s natural climate warriors, absorbing carbon dioxide and stabilizing ecosystems. Yet, as deforestation accelerates and global temperatures rise, the debate over the best approach to forest conservation intensifies. Should we focus on protecting ancient, old-growth forests, or is large-scale reforestation the key to reversing climate change?

Can We Replace the Irreplaceable?

Imagine an untouched forest, its towering trees standing for centuries, creating a complex, self-sustaining ecosystem. Now picture a newly planted forest, its young saplings growing in neat rows, promising a greener future. Both serve critical environmental functions, but are they truly interchangeable?

The Role of Old-Growth Forests

Old-growth forests—such as the Amazon Rainforest, Canada’s boreal forests, and the Pacific Northwest’s temperate rainforests—are ecological powerhouses. These ancient landscapes store vast amounts of carbon, regulate water cycles, and provide habitat for countless species. Their layered canopies, rich soils, and deep root systems create a biodiversity hotspot that cannot be easily replicated.

According to research, mature forests absorb significantly more carbon than younger forests. Their deep, undisturbed soils lock away carbon for centuries, preventing its release into the atmosphere. A study published in Nature found that old-growth forests continue absorbing carbon at a steady rate, making them vital in climate mitigation.

However, old-growth forests are rapidly disappearing. Logging, agriculture, and infrastructure expansion threaten these irreplaceable ecosystems. When cut down, the carbon stored in their biomass and soil is released, exacerbating global warming. Protecting these forests isn’t just about conservation—it’s about maintaining the planet’s most effective carbon sinks.

The Promise and Limitations of Reforestation

Reforestation—the process of planting trees in deforested or degraded areas—has gained momentum as a climate solution. Initiatives like the Bonn Challenge and the Trillion Trees Campaign aim to restore millions of hectares of forest worldwide. The logic is simple: more trees mean more carbon sequestration, right?

While reforestation holds promise, it has limitations. Newly planted forests take decades to mature and capture carbon at the levels of old-growth forests. Additionally, many large-scale reforestation projects focus on monoculture plantations—single-species tree farms that lack biodiversity and resilience. Unlike natural forests, these plantations often require intensive management and may not store carbon effectively in the long run.

Moreover, tree planting alone cannot offset continued deforestation. The World Resources Institute (WRI) estimates that we lose 10 million hectares of forest each year, far outpacing current reforestation efforts. Without simultaneously halting deforestation, reforestation becomes a futile race against time.

A Balanced Approach: Conservation and Restoration

Rather than viewing old-growth conservation and reforestation as competing strategies, a balanced approach is necessary. Preventing deforestation must be the priority—once an ancient forest is lost, it takes centuries to rebuild its ecological functions. Policies that protect primary forests, support Indigenous land rights, and enforce sustainable land-use practices are essential.

At the same time, reforestation should be strategic and science-driven. Instead of monoculture plantations, restoring diverse, native forests can enhance carbon sequestration and biodiversity. Agroforestry—integrating trees into agricultural landscapes—offers a way to increase tree cover while supporting livelihoods.

Organizations and governments worldwide must invest in both conservation and restoration efforts. Countries like Costa Rica have successfully combined forest protection with reforestation incentives, leading to a net increase in forest cover while boosting their economy.

Which Matters More? Or Do Both Matter Equally?

Old-growth forests and reforestation are not mutually exclusive. While protecting ancient forests must take precedence due to their irreplaceable ecological roles, reforestation can complement conservation efforts by restoring degraded lands and expanding green cover.

The real question is: will humanity act fast enough to preserve what remains while restoring what we’ve lost? The future of our planet depends on making the right choices—starting now.