How many trees should the UK parties plan to plant?

The Brexit party today joined the other major parties in promising to plant millions of new trees in an effort to appeal to climate-change-conscious voters in the election. Planting trees remains one of the cheapest and most powerful measures for reducing carbon emissions in the atmosphere. 

The Liberal Democratic party manifesto promises a plan to plant 60 million trees a year. Labour stated in its manifesto that it will ensure the NHS becomes a 'net zero-carbon service' linked with 'an NHS forest of 1 million trees'.

The Conservatives have said they will plant 30 million trees a year by 2025 if they win the election, half as many as the Liberal Democrats. Spending figures for the period between 2015 and 2018 reveal that forestry spending dropped by almost £20m a year during the time when the Conservatives governed. Tree-planting in England failed to hit its targets in the past year.

In its general election policies launched today, the Brexit party stated that it will invest in the environment via planting "millions of trees" to capture CO2, thus remaining vague over how many it wants to plant. It also stated that it would "promote a global initiative at the UN".

To what extent do these promises fulfil the 2050 net-zero goal the UK announced in June this year? The Committee on Climate Change (CCC) urged in its 'Net Zero' report published in May that the country would need to raise its afforestation efforts. By 2050, it would need to achieve a sustained increase in tree-planting rates, from the current rate of just below 10,000 hectares per year to at least 30,000 hectares per year, to reach the net-zero carbon emission goals in 2050. 

The number of trees needed by then would translate into roughly 1.5 billion trees, or around 48.4 million trees a year. 

Today's planting rate is much slower. In its last report for 2018/19, the government claimed fresh progress to meet its goals in planting 11 million trees within its five-year plan running from 2017 to 2022. E&T finds it to be a fraction of both what is needed and the rates suggested by the Conservatives and Lib Dems. The Liberal Democrats pledged to plant 30 times the 2018/19 rate of 2.1 million trees.  

In July, a new study was published which found that 1.2tn native tree saplings could naturally grow worldwide. 

In 2017, an analysis by E&T found evidence that councils in London were chopping down trees at an unprecedented rate. 

Another analysis from 2018 found that England may run soon out of oak trees.