“The proposals we are having to consider are extremely difficult and upsetting for everyone,” he said.
“We are looking at potentially cutting or reducing some of our high-profile and much-valued programmes.
“None of us want to make these decisions but they cannot be avoided unless there is significantly better news from the government on our funding.”
The restructure is expected to be concluded ahead of a meeting on 21 March, when members will agree next year’s budget.
A spokesperson for the Department for Environment, Food and Rural Affairs (Defra) said: “Our national parks and green spaces are a source of great national pride.
“That’s why this government is investing £400 million to protect and restore nature, including in our national parks.
“However, we will go further and give people better access to nature by creating new National River Walks and three new National Forests for families to enjoy.”
