Old Growth Forests: What they Are and Why They Matter

Forests currently absorb around 30% of all global carbon emissions. And of that, the world's largest and oldest trees are estimated to store a whopping 50% of all the aboveground carbon. But when old trees are cut down, they release their stores of carbon right back into the atmosphere. This is one of many reasons why it is particularly important to protect old growth forests. Where carbon storage is high, plant and animal diversity tends to be richer than anyplace else. 

The cool, shaded environments that older-aged forests provide is a much-needed respite for sensitive species, and for those that need time to migrate and adapt to a changing climate. Large trees create increasingly rare pockets of complex habitat for threatened and endangered aquatic and terrestrial species. And it doesn't stop there — the canopy of these forests have their own ecosystem, often supporting a range of mosses, lichens, insects, and birds — and even seedling trees where there are pockets of soil on branches.

Healthy trees and forests act as an all natural water treatment system. They can catch rainfall, regulate stormwater runoff, and purify waterways by absorbing pollution that is in the soil. Across the world, human settlements big and small rely on the services provided by forested areas for their clean drinking water. And if you haven't guessed yet, old growth forests excel particularly well at this — these same services also help reduce the impacts of extreme weather events such as forest fires and floods.

Majestic old-growth trees, the ring of bird song, the rustle of woodland creatures in the undergrowth and the canopy above — it's no small wonder that old growth forests attract visitors for a range of recreational activities such as hiking, camping, educational programming, forest bathing, and more. And of course, these recreational activities provide social and economic benefits to local communities.

Old-growth forests also help people breathe easier, both by intercepting particulate air pollution and by absorbing harmful greenhouse gases such as nitrogen dioxide and ozone. One famous example of this? The Amazon Rainforest produces and estimated 20% of all oxygen that is produced on land.

Approximately 28% of the Earth's land area is managed by Indigenous peoples, and we are very fortunate for that. What they give, the land gives back: the old growth forests that indigenous peoples have called home for time immemorial provide priceless cultural, medicinal and ecological value to these communities, extending far beyond subsistance activities such as hunting, gathering, and fishing.

While every old-growth forest is unique, what they have in common is a constantly growing and changing complexity that promotes symbioses among the species that call them home. Cast your eye anywhere in an old-growth forest and you will likely see several different species of mosses and lichen, broken branches, trunks that are cracked open, many species of trees, decaying “nurse logs” on the forest floor, a vast and layered canopy above. Over time, all these conditions have created pockets for a wide variety of life. According to scientists, this diversity is essential for resilience against a changing climate, protection against disease and infestation, encouraging genetic and species biodiversity, and more.