The project for what is thought to be Brown's first design will take shape across 40ha of rolling Northumberland countryside at his birthplace, Kirkharle.
The plans were rediscovered in a drawer in 1980, and the Forestry Commission has now pledged £4,000 for beech, oak, Scots pine, shrubs and fruit trees. English Heritage has also pledged to back the project.
Three blocks of woodland covering 3.5ha appear on the Kirkharle masterplan. The project should take around 18 months to complete.
The new scheme is being masterminded by John Anderson, who owns the Grade II-registered parkland, along with Kirkharle Creative, a local community group.
Anderson discovered the original sketch hidden away in a desk nearly 30 years ago. "It's possible that the design reflects actual elements of the 18th-century grounds, but it mainly contains Brown's ideas for the way it could be improved," explained Anderson.