38 environmentalists and students from Abingdon and Witney College helped to plant 1,000 trees outside Ascott-under-Wychwood in West Oxfordshire.
The 1,000 trees consist of oaks, willows, hawthorns and other native trees and bushes to help stop soil erosion and flooding from the river Evenlode.
The project was coordinated by the Wychwood Project charity, established to help preserve the former Norman royal hunting forest.
Helen Datson of the Wychwood Project said: “It was a very successful day.
“The weather was kind, it was extremely muddy and we were up to our calves sloshing about but the conditions for planting were good and we had a lot of fun.”
Thursday’s task was planned with help from the Evenlode Catchment Partnership, another environmental group who are helping stop flooding on the river.
The new woodland will also provide a home to a broad range of animals from insects to birds and mammals.