The organisation made the announcement, which it says will cost £90m-100m, on Thursday to mark its 125th anniversary.
By the end of the decade, it says the new trees and natural regeneration of woods will cover more than 18,000 hectares (44,000 acres), an area one and a half times the size of Manchester. It will mean that 17% of the land the National Trust looks after will be wooded, up from 10%.
The focus will be on planting on farmland – including in upland areas – that the trust owns, rather than in country estates, but the director general, Hilary McGrady, said the National Trust would be working with farmers to deliver the targets.
The charity says a similar level of tree cover is needed nationwide to meet government targets to cut greenhouse gas emissions.
Other initiatives announced by the trust include maintaining peat bogs, investing in more renewable energy and cutting its carbon footprint.
Efforts will focus on the National Trust’s own pollution, but McGrady acknowledged the impact of visitors, many of whom travel by car to the organisation’s properties.
She said the trust was measuring the impact of visitor emissions and suggesting ways to encourage more sustainable transport.
The charity, which was founded in the 19th century to protect and care for natural and historic places, plans to work with other organisations to create “green corridors” that connect people in urban areas to nature.
“As Europe’s biggest conservation charity, we have a responsibility to do everything we can to fight climate change, which poses the biggest threat to the places, nature and collections we care for,” McGrady said.
“People need nature now more than ever. If they connect with it then they look after it. And working together is the only way we can reverse the decline in wildlife and the challenges we face due to climate change.”