England’s largest temperate rainforest is set to become a protected nature reserve.

The Borrowdale Valley in Cumbria was declared a national nature reserve by Natural England and the National Trust on Wednesday.

This means the 721-hectare National Trust site has been marked out as an area of focus for conservation and nature restoration efforts. 

Once abundant in the UK because of the oceanic climate, temperate rainforests now cover less than 1 per cent of England’s surface.

Borrowdale, which is as wet as a tropical rainforest albeit much cooler, regularly sees the highest rainfall in England.

The humidity and low-temperature range make it a globally rare biodiverse habitat, with lush woodlands that are full of mosses, ferns and lichens.

The area also provides the ideal breeding habitat for otherwise declining birds including the redstart, pied flycatcher and tree pipit, and is one of the few remaining strongholds for native red squirrels.

The upland woodlands are rich carbon stores full of rare lichens, mosses and liverworts. These specialised plants hold an important place in a busy farmed landscape.

Conservation efforts will focus on supporting and restoring many of these species, the organisations said.

The National Trust said it is also aiming to modify some carefully selected sections of the existing paths to make them more accessible and protect Borrowdale’s longstanding cultural heritage.

The charity added that it is working with tenant farmers to help them access payments for further conservation work as they prioritise traditional practices which have shaped the landscape for generations, such as traditional fell farming.

Over time, the plan is for the nature reserve to grow so it includes other vital parcels of woodland in the area, helping to create wildlife corridors.

Jane Saxon, general manager for the north and west Lakes at the National Trust, said: “The new declaration is a testament to the increased focus on caring for and enhancing the rainforest while celebrating the impact this unique landscape has had on the natural and cultural heritage of the Borrowdale valley.

“By creating this nature reserve, we are actively managing the woodlands for nature conservation and access through compatible practices.”

Marian Spain, chief executive at Natural England said: “This landmark declaration is an important step forward for nature recovery in England.

“Operating at a landscape scale, reconnecting parcels of the forest and creating corridors for wildlife will make these iconic habitats more resilient to the impacts of climate change.”

Pete Barron, a local resident and conservationist, said: “With having lived within sight of this woodland now for 30-plus years, it’s part of my life.

“The access and special qualities of the woods are highly valued by the local community all year round.”

The nature reserve status comes as part of the Government’s temperate rainforest strategy – a new plan to recover these habitats found in Cornwall, Devon and Cumbria, backed by £750,000 in research and development funding.

It comes as Bradgate Park and Swithland Wood in Leicestershire, which inspired Sir David Attenborough when he was a child, was also declared a national nature reserve on Monday as National Nature Reserves Week kicked off.

These reserves are the latest to be declared as part of the King’s Series of National Nature Reserves as he supports Natural England to leave a lasting legacy for people and nature.

The Environment Department (Defra) also announced the extension of the Moccas Park and Gillian’s Wood national nature reserve in Herefordshire on Wednesday.