Avoiding Cutting Down Palm Trees For its Fruits in Amazonia Can Reduce Economic and Environmental Damage

Researchers at the University of Leeds and the Peruvian Amazon Research Institute (Instituto de Investigaciones de la Amazonia; IIAP) have found that cutting down the palm tree Mauritia flexuosa for its fruits had caused ecological and economical disturbances in Peru.

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The scientists have prepared a detailed study to show why and where the palm trees fell down and the extent of the economic and environmental damage caused by it.

“Cutting down female palm trees to harvest the fruit has halved the total production of the fruit of this palm that is available to local communities,” said Gabriel Hidalgo, a postgraduate student at Leeds’ School of Geography and lead author of the study.

“This is a clear example of the impact of humans on natural resource levels, in an ecosystem that, on first look, appears undamaged. However, changing the way the fruit is harvested can increase both the number of fruit-bearing palm trees and the value of these Amazonian peatland ecosystems to people.”

The study used data obtained from 93 places across the swamp forests found on the vast lowland tropical peatlands in northeastern Peru. Mauritia flexuosa, the most common species of tree in the peatland ecosystems, has the highest concentration of carbon of any part of the extensive Amazon region.

The fruit of the palm trees known as aguaje is broadly used in the preparation of drinks and food. The fruits are an important source of the economy in northern Peru. The sale of these fruits represents 15-22 percent of family incomes.

Mauritia flexuosa is a dioecious species which means there are both male and female trees. Out of the two, only the female trees bear the fruits. As many female trees are cut down for their fruits, the forests mostly contain male trees and thus produce less number of fruits.

The number of male trees increases and the number of fruits decreases.

The research team discovered that there are few places where the number of fruit-bearing female trees is large as there the fruits are gathered by climbing the trees instead of cutting them.

The alternative harvesting method, climbing, avoid killing of the trees which take 10 years to grow up to 40 metres in height and reach maturity.

The research team in collaboration with researchers at the University of St Andrews and Wageningen University in the Netherlands has evaluated that acquiring the harvesting method of climbing the trees could increase the harvest by 51 per cent and make $62 a year for the local economy.

“This study shows that financially, over the long term, the potential value of the palm fruit ‘aguaje’ for this region of Peru is similar in value to activities such as logging and oil extraction. Sustainable palm fruit harvesting could therefore provide a real economic alternative for local people,” said Dennis del Castillo, head of the PROBOSQUES research group at IIAP.

Increasing the number of these trees in the forests would bring vital environmental benefits. The tropical peatlands are one of the carbon-rich landscapes. This carbon is significant for reducing the amount of greenhouse gases emitted into the atmosphere.

These forests are also a great source of resources and add high cultural value to indigenous communities. The fruit of Mauritia flexuosa is a food source for mammals, fish and birds.

Dr Euridice Honorio, a NERC Knowledge Exchange Fellow on tropical peatlands at the University of St Andrews, started estimating the proportion of the female trees as a sign of the impact of resource extraction on the ecosystems. “This is the first estimate of the total value of this resource to communities in this region and will help to promote sustainable fruit harvesting by communities,” she said.

“Reducing deforestation of tropical forests is a global priority to mitigate climate change. Achieving success depends on increasing the value of standing forests to people who live in these landscapes. This study demonstrates a pathway to do this in one of the most carbon-rich landscapes on the planet,” said Tim Baker, Professor of Tropical Ecology and Conservation at Leeds’ School of Geography.

The detailed research has been published in the journal Nature Sustainability.