It comes after Eastbourne Borough Council teamed up with Eastbourne Eco Action Network CIC
It was to support the Eastbourne United Nations Association's carbon offsetting scheme in Uganda.
In a scheme that has so far seen 175,418 trees planted in Uganda, a council donation of £7,000 will see another 14,000 trees helping to sequester carbon in the African country.
Andrew Durling, Chief Executive of Eastbourne Eco Action Network, said: "Airbourne is the biggest festival in Eastbourne's yearly calendar and inevitably has a large carbon footprint, primarily due to the many thousands of visitors coming into town by car throughout the festival.
"While measures to decrease the festival's carbon footprint over time are being taken, there is a need to offset the current carbon emissions as much as possible. Much of that will be done within the borough through initiatives such as tree-planting schemes run by Treebourne, but the scale of offsetting needed is more than can be accomplished within the borough alone."