A new Western Forest is to be created across a swathe of the west of England from the Cotswolds to the Mendips, the government has said.

The project, one of the government’s promised national forests, will create 2,500 hectares (6,200 acres) of woodland by 2030 across five priority areas in Wiltshire, Gloucestershire, Somerset and Bristol, with plans to plant 20m trees by 2050.

The government said the announcement was a first step in meeting its manifesto commitment, and would bring trees and woodlands closer to people in cities and towns such as Bristol, Gloucester and Swindon.

The scheme is the first new national forest for 30 years – following on from the establishment of the National Forest in the Midlands – and aims to increase woodlands and tree cover to boost wildlife, help to mitigate the climate crisis, and provide access to nature for people.

Nearly three-quarters of the planned forest’s area is farmland, and the Western Forest will look to integrate trees into the farmed landscape through agroforestry and farm woodlands, which can regenerate soil and protect against drought and flood while producing food.

The project would also work to revitalise existing woodlands and other important natural habitats, officials at the Department for Environment, Food and Rural Affairs (Defra) said. In addition to 2,500 hectares of new woodland, there are plans to bring 1,500 hectares (3,700 acres) more into sustainable management by 2030.

The Western Forest would be spearheaded by the Forest of Avon, one of England’s community forests, and supported by up to £7.5m of government funding over five years, Defra said. The money will help create new woodland that connects established woods, as well as creating mixed habitat and supporting community planting in locations where trees can contribute to alleviating floods and slowing flows of water in storms.

The nature minister, Mary Creagh, said: “We will plant 20m trees in the Western Forest to bring nature closer to people, prevent flooding and support wildlife.”

Alex Stone, the chief executive of the Forest of Avon Trust, said the project would enhance landscapes and improve the lives of the region’s 2.5 million residents, as well as visitors to the area.

She added: “The Western Forest will enhance, connect and improve our urban and rural landscapes, support investment into the region, create jobs and skills opportunities and bring the endless benefits we get back from planting and caring for our trees.”

The National Forest chief executive, John Everitt, said: “This initiative builds on the success of the National Forest in the Midlands, where planting more than 9.8m trees has transformed the landscape, benefiting wildlife, communities and the economy.”