An Araucaria tree juts out of Brazil’s misty Atlantic Forest. Photo: Douglas Scortegagna/Wikimedia Commons, CC BY-SA

For hundreds of thousands of years, the distinctive candelabra shape of Brazil’s Araucaria tree (Araucaria angustifolia) has defined landscapes on the southern edge of the country’s Atlantic forest. Humans have never known a world without these majestic evergreen specimens, but my latest research, conducted with colleagues in Brazil and Reading, suggests that their extinction could be just a generation or two away.

At first glance, you might mistake Brazil’s Araucaria for its sister species, the monkey puzzle tree, which is found in Chile and Argentina. But the two have inhabited South America as separate species for eons, after diverging some 28 million years ago.

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If you compressed those 28 million years into 24 hours, North and South America wouldn’t become one landmass until 9:30 pm. Humans wouldn’t appear until 11:45 pm. These are truly ancient plants.

Araucaria trees have been revered for as long as humans have lived in the highlands of southern Brazil. Their starchy, nutrient-rich pine nuts (known as pinhão) underpinned the diets of indigenous groups before the arrival of Europeans, especially in times of scarcity.

brazil argentina araucaria
Left: Brazil’s Araucaria angustifolia. Right: Chile and Argentina’s Araucaria araucana, or monkey puzzle tree. Photos: Shutterstock

The trees also hold great cultural importance. For example, the funeral ritual of the indigenous Kaingang people requires Araucaria knots to keep bonfires burning, Araucaria ashes for face-paint, and a trough made from an Araucaria trunk to hold a traditional fermented honey drink. The Xokleng people even used to define their calendar by the seasons of the pinhão.

Today, pinhão are a regional delicacy, with trade worth millions each year and an annual festival held in their name. But while Araucaria trees are now most valued for their nuts, it was their excellent timber that first led to their downfall. Brazil’s strong economic growth in the 20th century fuelled an unsustainable demand that consumed an estimated 97% of the country’s Araucaria trees. Using our analogy of 28 million years in 24 hours, the species fell from being widespread to “Critically Endangered” in a third of a second.

Sadly, the short-sighted culture of consumption that drove the dramatic decline of the Araucaria hasn’t gone away: human-caused climate change is now threatening to tip the species into extinction. Araucaria trees are adept to relatively cool, constantly moist conditions—which are slowly disappearing as the planet heats up and normal rainfall patterns are disrupted.

Using data on current and predicted temperatures and rainfall, as well as high-resolution maps that include small-scale terrain features, we modelled the likely fate of Araucaria trees over the coming decades. We found that projected climatic changes are likely to significantly loosen Araucaria trees’ grip on its current strongholds in southern Brazil. Our most optimistic scenario predicts an 85 percent loss of the tree’s most suitable habitat by 2070, and several scenarios predicted that this habitat would vanish altogether.

Though these findings are worrying, we were able to identify some potential refuge for Araucaria—areas where the trees have at least a three-in-four chance of surviving long into the future. These are mainly found in colder spots in the landscape, such as sheltered slopes or river valleys where cool, moist air will continue to gather, even as the wider region becomes more inhospitable.

atlantic forest
Darker and redder areas of Brazil’s Atlantic Forest are more climate-resilient. Areas in greyscale have already lost their natural vegetation. Image: Oliver Wilson/Wiley, Author provided

Unfortunately, the legacy of past destruction means that more than a third of these areas have already been deforested, built on, or converted to agriculture and timber plantations. Only 2.5 percent of the remaining area is under any sort of protection, with most of it lying within just two national parks. With the current Brazilian government’s push to loosen environmental protections in pursuit of quick economic gains, these areas may not remain safe for long.

Conserving an ancient icon

While none of our findings are good news for Brazil’s Araucaria, it is not necessarily doomed. There are steps that we can take to ensure its continued survival in Brazil’s southern highlands.

Clearly, all of us must combat climate change and rein in the consumption which drives it. Beyond that, actively protecting Araucaria forests from unsustainable extraction is a top priority. This means keeping existing protected areas safe and creating new ones—especially where these small areas of refuge are vulnerable to damage. It also means working with private landowners outside these areas. While Araucaria forests are better protected in conservation areas, traditional methods of grazing cattle or producing maté tea under the forest canopy can support livelihoods without significant damage to Araucaria populations.

And for truly long-term conservation planning we could learn a lesson or two from the past. Evidence suggests that indigenous people helped Araucaria forests expand beyond their natural boundaries around 1,000 years ago, though how and to what extent isn’t yet clear. Investigating how millennia of climate change and centuries of human actions combined to shape the present-day Araucaria forests may reveal ways of helping them survive the grave challenges of the coming decades.

We are living through the most turbulent point in the long history of Brazil’s Araucaria. Our actions in the next split-second of its 24-hour life will determine whether or not future generations have the chance to treasure this ancient icon.

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MoneySep 18, 2019

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BY Oliver Wilson

Ph.D. Researcher in Environmental Science, University of Reading