The animals’ natural behaviour of grazing, felling trees, eating bark and taking dust baths opens the canopy, allows woodland regeneration and creates new spaces for other wildlife.
Wildlife monitoring and research will show, over time, what effect the bison are having.
But Hannah Mackins, bison and conservation grazing ranger, said they were already starting to see a difference in the part of the wood they have been in until now.
“Walking through there, we have a lot more light on the woodland floor, we have species growing through that wouldn’t have had before, because it was so dense with trees, bracken and brambles,” she said.
“They are having a great impact already.”