David Musson, who has died aged 79, devoted his career and retirement to the National Trust and the conservation of the English countryside.

Mr Musson, a retired National Trust land agent and regional director, raised more than £1m for the charity over 20 years through selling second-hand books and stamps, benefiting projects at Blickling Hall, Felbrigg and other properties.

Brought up mostly in Kent, Mr Musson was determined from a young age to work for the Trust, whose work impressed him.

He studied land management at London University, joining the charity after graduation and remaining for 53 years.

He became land agent in East Anglia, and then regional director for the southern region.

Within weeks of Mr Musson's arrival in Norfolk, in 1969, for his first job, the squire of Felbrigg Hall, Wyndham Ketton-Cremer, left his estate to the National Trust and it was Mr Musson's responsibility to oversee the transfer.

After retirement, he moved to live in Sheringham – with fine views for bird watching, another great interest.

He took his first voluntary job as a room steward at Felbrigg Hall, where in 1996 he oversaw the opening of a second-hand bookshop, the first of its kind anywhere in the National Trust.

Its proceeds funded the walled garden, the 1750 library ceiling and many other much needed conservation projects.

As a result of his initiative, a second bookshop opened at nearby Blickling Hall in 1999, and is the Trust's most successful, bringing in more than £100,000 each year.

Mr Musson also later opened a shop selling second-hand stamps at Blickling which is currently funding the restoration of the stately home's walled garden.

A committed member of the British Trust for Ornithology (BTO), he travelled to their base in Thetford from Sheringham one day each week to work in the ringing office, extracting key information required from worldwide correspondence.

He priced and sold legacies of books for the BTO, sold his own collection of natural history books for the cause, and received the BTO's Jubilee Medal in 1997 in recognition for his voluntary work.

A National Trust spokesman said: 'It is hard to quantify how much richer the organisation is for having such selfless and visionary individuals walk its colonnades and country paths, but those ripples will be felt by future generations who - thanks to the hard work and dedication of people like David - will still be able to reach out and touch the historical and cultural heritage of this beautiful county… hopefully with a quite reasonably-priced second-hand book in tow.'

Mr Musson's funeral will take place at St Faith's Crematorium, Norwich, on Tuesday, November 3 at 12.30pm.