Staff at the National Forest have said they will fight for compensation if a proposed HS2 high speed rail route through its woodland gets the go ahead.
The preferred route of phase two goes north from Birmingham to a new station at Toton Sidings, near Nottingham.
The route would pass directly through woodland - covering an area of 200 sq miles (320km) in Leicestershire, Derbyshire and Staffordshire.
Chief executive Sophie Churchill said trees and wildlife would be affected.
She said: "The National Forest Company is a strong advocate for sustainable development, which includes sustainable economic growth.
"However, this is potentially another major transport route cutting a line right across the forest, and one which by the time it comes about would require the removal of considerable semi-mature trees, up to 40 years old.
"It will also affect wildlife and biodiversity and be disruptive to communities."
The preferred route of phase two running northwards from Birmingham will have stops at: Manchester, Manchester Airport, Toton, Sheffield and Leeds.
Ministers say the railway will stimulate regional economies, and it has been welcomed by some business leaders.
But critics say the plan is flawed, saying it will blight the countryside and require public subsidy.