More than half of the tree cover in Pacific atolls is largely composed of “abandoned and overgrown” colonial-era coconut palm plantations, reveal satellite images in a study published in December 2024.
What the study says:
- While coconut palm is an integral part of the cultures and economy of Pacific Island communities, colonial powers have driven a rapid spread of coconut plantations on Pacific atolls over the last 200 years, primarily to supply the global coconut oil market. Yet, the extent of these coconut plantations hasn’t been fully mapped, said researchers from the University of California, Santa Barbara (UCSB), U.S., and The Nature Conservancy (TNC).
- To fill this gap, the researchers analyzed 460 satellite images with the help of machine learning, producing very high-resolution vegetation maps of 235 out of the 266 Pacific atolls. The maps showed that coconut palms covered 58.3% of the islands’ tree cover, surpassing native broadleaf trees in terms of canopy area.
- The study found that 51.2% of the coconut canopies occur in monocultures. “Even on atolls where planting and harvesting ceased decades ago, former coconut plantations persist and exclude competing vegetation,” the authors wrote.
- The researchers also compared atolls with climates equally suitable for coconut palm and found that atolls that historically exported coconut products had on average 32.1% more coconut canopy coverage. The researchers wrote that this shows the “significant and persistent effects of plantations on forest compositions in the tropical Pacific.”
- In general, the study found that coconut palms occurred more in large, wet islands, “reflecting their high rates of water use and thus their potential to deplete critical groundwater resources.” This, the authors wrote, suggests that the islands’ native vegetation, which is important for wildlife and soil formation, were deprived of the needed resources due to the spread of coconut plantations.
What this means:
“Coconut oil used to be essential to atoll economies, but today most coconut palm plantations are abandoned and overgrown,” lead author Michael Burnett from UCSB said in a statement.
Burnett added that with Pacific atolls facing growing climate threats, “it’s critical to figure out where these abandoned plantations are using up critical land and water resources, and where there may be opportunities to restore the native forests to the benefit of islands and islanders.”
Atolls also play an important role in ocean health, which is why restoring their ecosystems should be a priority, said Alex Wegmann, study co-author and lead scientist for TNC’s Island Resilience Strategy.
Elizabeth Terk, Micronesia conservation director for TNC, added that restoring the atolls’ abandoned coconut plantations to native forests would help their native biodiversity recover and aid in climate resilience, although “striking a balance between cultural heritage and environmental stewardship is essential.”
The researchers said that mapping the atolls’ tree cover is an important first step in this direction.
Banner image of coconut palm in Palmyra Atoll by USFWS/Andrew S. Wright via Flickr (CC BY-NC 2.0).
