ONE of the country's foremost experts on nature conservation has died.

David Arnold-Forster, chief executive of English Nature, died yesterday as he looked forward to returning to work following treatment for cancer.

A native of Skipton, North Yorkshire, Mr Arnold-Forster worked for the Ministry of Defence in the field of arms control, especially chemical weapons, and played a part in the reconstruction of post-war Bosnia.

He is best known in the region for his six years in charge of the North York Moors National Park Authority.

He became chief executive in 1994 at a critical time for the authority and oversaw the change to independent local government status. He went on to initiate a series of radical conservation plans for moorlands, rivers and farms across the national park and is remembered for his boundless enthusiasm for the task.

In January 2000, Mr Arnold-Forster was appointed to the top job at English Nature, making him the Government's most senior advisor on nature conservation.

Later the same year, the then Agriculture Minister Nick Brown appointed him as chairman of the Hills Task Force to identify ways in which the Government could assist upland farmers in developing sustainable businesses. Friends said he was especially proud of the role because of his deep concern for hard-pressed hill farmers.

Sir Martin Doughty, chairman of English Nature, said: "His organizational skills impressed me hugely and his energy was breathtaking.

"David was a human dynamo. It is a cruel blow that someone with so much to offer should die so young.

"Our heart's go out to Anita, David's wife."