Countryfile's Plant Britain aims to combat climate change and boost wellbeing and wildlife. Woodland Trust are providing the opportunity to apply for trees as part of a special ballot or through their free tree packs scheme.
The BBC said the 750,000 trees match the 750,000 children who will be starting primary school in September.
On 29 November on BBC1, Matt Baker is in Cheshire, planting the first trees, supplied by Woodland Trust, in what will become the Countryfile Plant Britain wood, while Anita Rani is in Bradford, helping residents of the Canterbury Estate to plant trees in their front gardens and at the local primary school and in Hackney with voluntary organisation Tree Musketeers.
Margherita Taylor is at Wytham Woods in Oxfordshire, discovering how trees capture carbon. Steve Brown is in Neath, south Wales, to learn which trees to plant in which location, while John Craven discovers a micro-forest and Ellie Harrison visits Westonbirt Arboretum in Gloucestershire.
There are also messages from tree lovers HRH The Prince of Wales, Dame Judi Dench and Brian May.
