Ancient, or old-growth, forests are found on every continent with remaining native woodland: from coastal temperate rainforests to boreal taiga and tropical lowland forests. You can experience them in protected parks and national forests where large trees, multi-layered canopies, standing deadwood, and complex soils have developed over centuries. These ecosystems are not only scenic; they are central to biodiversity, carbon storage, and many human cultures.
Temperate and boreal old-growth
In the Pacific Northwest of North America, the Hoh Rainforest in Olympic National Park managed by the National Park Service preserves temperate old-growth with massive conifers and thick epiphyte cover. The Tongass National Forest managed by the U.S. Forest Service contains some of the largest remaining tracts of temperate rainforest and is also an important site for Indigenous stewardship and subsistence uses. Research by Suzanne Simard at the University of British Columbia demonstrates how mycorrhizal networks and belowground connections in these forests support resilience and nutrient cycling, a scientific explanation for why intact old-growth functions differently from second-growth plantations. In boreal regions, pockets of ancient forest survive in Siberia and northern Canada where long-term disturbance has been limited; these areas harbor specialized species and store large amounts of carbon in soils.
Tropical and southern-hemisphere old-growth
Tropical old-growth, such as intact Amazonian forest reserves studied by institutions like the National Institute for Amazonian Research in Brazil, contains the highest terrestrial species richness and complex carbon dynamics. In Australia, the Daintree Rainforest administered by the Queensland Parks and Wildlife Service and Tasmania’s remaining old-growth areas protected under state conservation programs preserve unique lineages and endemic species. Conservation ecologist David Lindenmayer at the Australian National University has repeatedly emphasized the irreplaceable biodiversity values of long-unlogged forests, showing that many species depend on structural features that develop only over centuries. Visiting these forests offers encounters with evolutionary history that cannot be replicated in managed plantations.
Relevance, causes, consequences, and responsible visiting
Old-growth forests matter because they concentrate biodiversity, regulate local and global climate through carbon storage, and sustain cultural practices. The Intergovernmental Panel on Climate Change reports that conserving intact forests is a critical climate mitigation measure because their soils and biomass hold long-term carbon. The primary historical causes of old-growth loss are industrial logging, agricultural conversion, and road building; contemporary threats include intensified logging, fragmentation, and climate-driven disturbances such as drought and fire. Consequences of continued loss include species extinctions, released carbon, and erosion of cultural connections for Indigenous peoples. Writer and scientist Robin Wall Kimmerer at the SUNY College of Environmental Science and Forestry highlights how Indigenous knowledge and co-management can sustain both ecological function and cultural obligations to forests. When visiting, prioritize parks and reserves with clear protection, follow local guidance, and support stewardship led by Indigenous communities to reduce impact and reinforce conservation.