I grow 3 varieties of Xmas trees, have done for 20 + years, needs to be well hiddden though else people nick them as you approach the festive season. You can get Forestry Commission or Natural England grants I think for planting native broadleaves and higher proportion for orchards etc (not for Xmas trees though, but 30cm saplings can be had for a £1, you’ll have big enough ones to sell in about 4-6 years). Planting for Coppicing worth looking at for supplying poles (not the nation) and charcoal burners. All depends on the land and what might grow best there – look what does best surrounding it.
Renting it out to horsey types can be an earner but to pay a fair whack they’ll want good access, water supply and decent stock fence / hedges. And then still probably moan about something.
Use for camping/events for up to 28 days a year, you don’t need planning permission /licence.
Cameron’s mate Hugh Fearnley Whittingstall used to do that land share thing where you let people grow stuff on it (take some produce in return).
I want to do this on our land: http://www.history.co.uk/shows/seeking-salvage but Mrs won’t allow.
Otherwise don’t do anything and just use as an escape to camp on yourself & enjoy