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Primary Forest Overview


Earth’s spectacular primary (“old growth”) forests are unique and irreplaceable. They are the homelands of Indigenous Peoples and essential to the livelihoods of local forest communities, they are essential to cultural diversity, they protect over two thirds of the planet’s land and freshwater species, including countless endangered species, they are natural quarantine areas, preventing the spread of zoonotic diseases like COVID19, they fight climate change by storing vast amounts of carbon and drawing down carbon from the atmosphere and they ensure reliable, high quality freshwater supplies. Primary forests are essential life-support systems, critical to addressing many of our most urgent environmental and social problems.

Primary forests and large, old trees provide unmatched biodiversity, clean water, and carbon benefits (our Chief Scientist, Dr. Dominick DellaSala and Dr. William Moomaw summarize their values.

Giant sequoia in the Sierra National Forest
Photo: D. DellaSala)

But they are going fast. We’ve already lost over a third of Earth’s forests. Less than a third of our remaining forests are primary and we lose millions of hectares of primary forest each year. We have not succeeded in making industrial activity – including industrial logging – sustainable in primary forests, even with best practices. We urgently need to protect our remaining primary forests.

All primary forests are critical, large or small, wherever they are found! Even small patches are important because they are essential building blocks and providing the seed banks and seed dispersers (birds, pigs, monkeys etc.) we need to bring the forest back where it’s been cleared. We need to protect these patches and do ecological restoration work around them to buffer and reconnect them to larger areas of forestWe need to stop the destruction, degradation and fragmentation of all of Earth’s remaining primary forests if we want to maintain a livable planet, and we need to act now: our planet is on fire and we are running of time!

Primary Forest Frequently Asked Questions

What is a primary forest?

A primary forest is a forest that is the result of natural processes rather than human management and that has not been degraded by industrial activities. Mature trees dominate the canopy and a primary forest contains most or all of its native plant and animal species. Primary forests include all successional age classes (young to old-growth) having no industrial human activities, including primary forests regenerating after wildfire.

More specifically: a primary forest is a forest whose vegetation structure, species composition and ecosystem dynamics are predominantly the product of natural physical, ecological and evolutionary processes, including natural disturbance regimes such as fires, storms and landslides. Primary forests retain all, or the large majority, of their evolved, characteristic native plant, animal and microbial species, have few if any invasive species, are dominated at the landscape scale by mature canopy trees, have unpolluted waters, contain extensive coarse woody debris, and have not been subject to industrial land use activities such as commercial logging, mining and ranching.

As a “chapeau” term, primary forest covers a range of related terms including “old growth forest”, “ancient forest”, “primeval forest” and “intact forest landscapes”.

Why are primary forests important?

Primary forests are irreplaceable life-support systems. They ensure a wide range of vital ecosystem services that are either unique to primary forests, or that are of a superior quality and quantity to other forest types (such as degraded forests, secondary re-growth forests, plantations). In particular, they:

  • Protect the most biodiversity (plant, animal and microbial species, functional types, complex food webs, co-evolved species relationships);
  • Store vast carbon stocks. Primary forest store much more carbon than degraded forests or plantations and their carbon stocks are also more stable because primary forests are more resistant to change, and more resilient. Primary forests also draw down more carbon out of the atmosphere every year. To avoid dangerous climate change, we must protect the massive carbon stocks already accumulated in primary forests.
  • Provide the cleanest freshwater, prevent erosion and help regulate local water cycles, and;
  • Prevent the spread of zoonotic disease to humans. Deforestation and degradation of primary forests and associated road building (e.g. logging or mining roads) enables bushmeat trade and wildlife trafficking and facilitates disease transmission to humans.
  • Are the homelands of Indigenous Peoples around the world and are crucial for sustaining traditional culture and community livelihoods. Primary forests have often remained in good condition because of community and indigenous stewardship.

Importantly, primary forests provide more and higher quality ecosystem services because of their higher levels of biodiversity and ecosystem integrity. So to protect a primary forest’s ability to provide its full range of benefits it is critical to protect it from inappropriate land use activities, including industrial disturbance.

How much primary forest is left?

We have already lost over a third (about 35%) of the planet’s forests. Of the planet’s remaining forests, less than a third (about 30%) or just under 1.3 billion hectares are primary forests.

How much primary forest are we losing?

According to the UN’s Food and Agriculture Organization we are losing about 4 million hectares per year, though FAO statistics on primary forests significantly underestimate loss because the government reports they are based on are not always reliable and some governments do not report on primary forest loss at all. The recent scientific literature suggests that forests are being fragmented and degraded at very high rates. For example, a study in 2015 found that 70% of the world’s forests were now within one kilometer of a forest edge (road, clearing, pipeline etc.). A 2017 study found that large, contiguous blocks of forest (50,000 hectares or more) had decreased by over 7% since the year 2000.

Why are we losing primary forests?

Industrial agriculture is a primary driver of deforestation globally, including of primary forests. Primary forests are being cleared to make room for crops such as palm oil, soy etc. and for cattle ranching. Oil and gas extraction and mining also contribute to deforestation, as do large-scale infrastructure such as roads and hydropower projects.

Primary forests are also being degraded primarily by commercial logging and by fuelwood gathering. Despite decades of efforts to develop best-practices for the logging industry, commercial logging has not proven sustainable in primary forests and often leads to total deforestation as degraded forests whose valuable timber has been removed are converted to agriculture.

In many regions, growing human populations are expanding the footprint of slash and burn agriculture. Helping communities farm more sustainably and develop alternative development pathways based on forest conservation is a prerequisite for protecting the world’s remaining primary forests.

What can we do to stop primary forest loss?

We know the range of mechanisms that are effective at protecting primary forests. Protected areas with good governance and adequate funding can successfully protect primary forests. Similarly, community conservation initiatives and Indigenous Peoples have a proven track record of protecting primary forests – often over millennia. Payments for ecosystem services schemes have also met with success. Conversely, it is crucial to stop viewing commercial logging as a sustainable and viable solution for protecting primary forests. Commercial logging has not proven sustainable in primary forests anywhere.

We need to “flip” incentive structures so that national and multilateral subsidies are directed to mechanisms that have demonstrated capacity to achieve primary forest protection – and to restoring degraded forest or regenerating forest. Currently, subsidies for industrial agriculture, extractive industries and other industrial developments far outweigh conservation funding. Shifting this balance to support actors on the ground that have a commitment and vested interest in keeping primary forests standing – especially indigenous and local communities – can have a profound and rapid effect on primary forest protection globally.

Help restore degraded lands and manage wildland fires safely!

Help restore degraded lands and manage wildland fires safely!