There have been 1.2 million government-funded trees planted in Northumberland between 2010 and 2018, Forestry Commission data shows.
This works out at 3,888 trees per 1,000 people.
Between 2010 and 2018 the government funded about 15 million trees in England. Figures for trees planted with private funds or by local councils are not included and the data only covers new trees, not replacements for any that were cut down.
Overall tree planting rates across the UK would need to more than double to combat rising temperatures and climate change, according to official figures.
Last year 13,400 hectares of new trees were planted across the UK, most of them in Scotland, but the Committee on Climate Change says this should rise to at least 30,000 hectares a year.
Campaign group The Woodland Trust said more trees were needed to provide summer shade, reduce air pollution, improve water quality and manage flooding.
The government said it had made it "much easier" to apply for planting grants.
Find out about tree planting across the UK here.
This story has been generated using Forestry Commission data, BBC analysis and some automation.