At the last election, the Conservative Party promised to plant millions of trees. But, as Reality Check correspondent Chris Morris reports, it is going to have to dramatically speed up the planting to meet the target.
Campaigners have called on the government to do more to address the "unacceptably low" level of woodland cover in the United Kingdom, arguing it is causing the country both economic and environmental damage.
Only 13% of the UK's total land area is covered in trees, compared with an average elsewhere in the EU of about 35%. In England, the figure is just 10%, and efforts to plant more trees have been falling short.
A statement from the Department for Environment, Food and Rural Affairs (Defra) says: "Planting more trees is at the heart of our work to protect the environment for future generations."
But critics say the government is not doing enough.
100 years to grow
On the Bromborough estate in Northamptonshire, four hectares (10 acres) of new woodland were planted two years ago.
It's a mix of fast-growing species such as grey alder, coniferous trees such as larch and Douglas fir, and species such as sycamore and oak that will take more than a century to reach maturity.
"It provides us with different products," says Justin Mumford, from the forestry consultants Lockhart Garrett. "But it also creates a resilient woodland, a robust woodland."
The trouble is, across the country, there isn't enough of it.
Tree planting is a devolved issue, so there are different policies in place across the United Kingdom.
But Stuart Goodall, the chief executive of Confor - which represents the forestry and sawmilling sector across the UK - says all of them are "failing miserably."
"There's a big need to plant trees both to provide a future supply of wood for the sawmilling industry in 20 years' time," he says, "but also to hit our climate change targets - we need to lock up carbon."
"So we're failing on both those counts."
Between 2010 and 2015, there were 11 million trees planted as part of government schemes in England.
The 2015 Conservative Party manifesto promised to plant another 11 million trees over the next five years, but planting was well behind schedule when the snap election was called earlier this year. In 2015-16, 642,000 trees were planted in England. In 2016-17, it was 802,000.
The 2017 Tory manifesto repeated the pledge of 11 million, and added that another one million trees would be planted in towns and cities. There is some catching up to do.
Elsewhere in the UK, the picture is mixed. Forest and woodland currently cover about 18% of Scotland, and the Scottish government intends to increase that to 21% by 2032. Its current target is to plant 10,000 hectares of new woodland every year, rising to 15,000 per year by 2024-25.
The Welsh government promised in 2008 to plant a tree for every child born or adopted in Wales, and in 2014 it extended that to plant another tree in Uganda for every child. This year, it plans to restock government-owned woodland with five million trees.
So both Scotland and Wales appear to be planting faster than England. But the overall lack of tree cover means the UK has now become the second largest net importer of timber in the world, after China.
"We buy a lot of timber in from France," says David Kinns, who owns a family-run sawmill and timber merchants near Milton Keynes, "in fact [our timber comes from] all over the world."
He too, is unimpressed with government targets.
"Eleven million isn't many trees. They'll take a long while to grow, and they won't all come to fruition."
The other problem with the Conservative manifesto commitment is it is almost impossible to say what 11 million trees means in terms of land area, because they can be planted at a density of anything between 1,000 and 2,500 per hectare.
Secondly, the government's five-year target is not a net figure, so it doesn't take account of the number of trees being cut down.
Conservation charity the Woodland Trust says it is extremely difficult to get an accurate figure for the number of trees being felled in England every year.
But it believes that England may have reached, or be on the cusp of, deforestation - cutting down more trees than it plants.
It puts the government's long-term ambition - of increasing woodland cover to 12% of land area in England by 2060 - into sobering perspective.
Meeting that target would require at least 5,000 hectares of tree cover to be added every year.
In the past few years, planting levels have been far below that.
Even the 12% figure is considerably lower than a recommendation made in 2012 by the Independent Panel on Forestry, which said the government should be aiming for 15% woodland cover by 2060.
In other words, tree planting in England is falling well behind a target many experts believe was insufficient in the first place.
So can anything be done?
Defra says it is committed to working with landowners to grow woodland cover. It highlights a new £19m Woodland Carbon Fund to encourage large-scale planting.
And it argues it has made it easier to apply for schemes such as the Countryside Stewardship Woodland Creation grant, which offers up to £6,800 per hectare to plant, weed and protect trees.
But again, some experts beg to differ.
There may be an increasing number of farmers who want to see trees forming part of their farming systems, but it has to be worth their while.
"There are all sorts of reasons at the moment why you wouldn't want to plant trees," says Beccy Speight, the chief executive of the Woodland Trust, "and there's not a huge amount to incentivise you to do so."
"As a farmer you can lose some of your basic farm payment if you have tree cover. So that's a problem."
The Woodland Trust also says the grant schemes that exist are still too complex and the timescale around applications is too tight.
A post-Brexit replacement for current schemes under the Common Agricultural Policy could provide one opportunity to change the way grants for farmers link up with trees and woods.
But, realistically, tree planting is unlikely to emerge as a top priority in what will be a complex negotiation.
Tree cover in the UK has increased considerably over the past century, after it reached a historic low at the end of World War One.
But the UK is still far behind comparable developed economies around the world.
And last year the rate of planting in England fell to its lowest level in more than 40 years.