A recent study by scientists from the Department of Environment and Natural Resources (DENR) has found that the remaining beach forest on Pag-asa Island in Kalayaan, Palawan, stores nearly 10,000 tons of carbon dioxide, making the country’s westernmost inhabited island an important carbon sink in the West Philippine Sea.
The research, published in the Philippine Journal of Science in August 2025, revealed that the 7-hectare beach forest holds a total of 375.58 tons of carbon per hectare, equivalent to 9,648.6 tons of carbon dioxide.
“Pag-asa Island’s beach vegetation plays a critical role in storing atmospheric carbon,” the study stated, adding that large-diameter native trees such as Barringtonia asiatica (botong) and Calophyllum inophyllum (bitaog) make up 94 percent of the island’s total biomass.
The study, conducted by the Ecosystems Research and Development Bureau (ERDB), marks the first scientific assessment of species diversity, community structure, and biomass carbon stock in Pag-asa’s beach forest.
Researchers identified 20 plant species from 19 families, with Calophyllum inophyllum and Barringtonia asiatica emerging as the most abundant.
Despite its ecological value, the study warned that Pag-asa’s forest cover has drastically declined, from 11.05 hectares in 2017 to only 1.77 hectares in 2023, based on satellite data. Built-up areas have expanded to 25.5 hectares, driven by increasing land conversion and infrastructure development.
The researchers urged the government to protect the island’s vegetation and called for reforestation using high-biomass native species and the establishment of a long-term monitoring system.
Their findings come as Congress deliberates a bill that seeks to declare the Kalayaan Island Group (KIG) and Scarborough Shoal as marine protected areas under the Expanded National Integrated Protected Areas System (E-NIPAS) Act.
In his explanatory note for House Bill No. 3090, Rep. Franz Fernandez Legazpi of Pinoy Workers Partylist said the measure aims to safeguard both the marine and terrestrial biodiversity of these contested territories.
“The Kalayaan Island Group and the Scarborough Shoal are biologically rich and ecologically significant clusters of islands, reefs, and atolls. These maritime features are home to diverse marine species, including endangered sea turtles, coral reef systems, seabirds, and commercially valuable fish stocks,” Legazpi wrote.
“It is imperative that we adopt a conservation-based approach to the governance of the KIG and Scarborough Shoal. This measure will not only help preserve the Philippines’ ecological patrimony but will also reaffirm our commitment to upholding responsible stewardship and sovereign rights over our maritime domains,” he added.
The Pag-asa Island study reinforces these conservation goals by highlighting the island’s ecological value beyond its geopolitical importance.
“Oceanic islands like Pag-asa provide vital habitats for coastal biodiversity and serve as significant carbon storage systems,” the researchers said.
They recommended that national agencies such as the DENR, the Department of Agriculture–Bureau of Fisheries and Aquatic Resources, and the Department of Tourism coordinate to develop a unified plan for conserving the island’s natural resources.
The authors concluded that protecting Pag-asa’s remaining vegetation is not only an ecological priority but also a symbol of the country’s environmental and sovereign stewardship in the West Philippine Sea.
