The Carbon-Storing Palm
The Palmyra palm, Borassus flabellifer, is a feature of the arid region of northern Sri Lanka, particularly in the Mannar district. While culturally significant, providing food, drink, and building materials for centuries, the tree possesses a less obvious quality: its ability to sequester large amounts of atmospheric carbon. A study conducted in the nearby Jaffna district found that Palmyra-dominated areas have an average total carbon stock of 108.53 megagrams of carbon per hectare (Mg C ha-1). This total includes both the carbon stored in the trees themselves (biomass) and within the soil.
The tree's effectiveness as a carbon sink comes from its physical structure. The wood of the Palmyra palm is remarkably dense, with some measurements showing 1020-1140 kg per cubic meter when air-dried. A detailed analysis of the palm's component parts reveals how this carbon is distributed. The woody trunk holds the highest concentration, with studies showing it contains up to 49.8% carbon. The leaves also store a significant amount, around 48.4% carbon. Even the extensive root system, which allows the palm to thrive in dry conditions, contributes to the overall carbon storage, with a concentration of about 42%. On average, the biomass carbon stock in these areas is estimated at 72.48 Mg C ha-1, with an additional 36.05 Mg C ha-1 stored in the top 30 cm of soil.