According to Prince Charles, coronavirus is challenging society "in a way that we have not experienced for generations".
The 71-year-old royal has underlined the scale of the challenge in an article for the National Trust magazine, in which he expressed his sadness that a 125th National Trust garden party at Buckingham Palace had been cancelled due to the pandemic.
The prince - who is marking a quarter of a century as the charity's president - said: "The global spread of coronavirus is challenging society in a way that we have not experienced for generations and as a direct impact it has, of course, necessitated the temporary closure of the National Trust's properties, parks and gardens too.
"Sadly, the situation has also forced the cancellation of the 125th Anniversary Garden Party that was due to take place at Buckingham Palace on Thursday 14th May, when I had much been looking forward to meeting many of you.
"While this is undoubtedly a great shame, I know the anniversary will not be overlooked and I shall do whatever I can to play my part in celebrating this important milestone - however remotely."
Prince Charles also hailed the work of the National Trust, which focuses on environmental and heritage conservation in England, Wales and Northern Ireland.
He wrote: "This year marks the 125th anniversary of the National Trust. It also happens to be my 25th year as President of this great British institution which, with your valuable support, continues to play a vital role in our national life.
"When our three founders established their new organisation in 1895 it would surely have seemed impossible to them, or indeed anyone else, that a membership of millions of people would one day own and support 250 000 hectares of farmland, 780 miles of coastline and more than 500 historic properties, together with glorious gardens and spectacular Nature reserves.
"This remarkable outcome is due not just to their vision, but to their insistence that owning land and property on behalf of the Nation was essential if it was to be saved for ever from the threat of development and loss of public access.
"We owe a huge debt of gratitude to those pioneers and to everyone whose support over the years has made the current situation a reality. Your membership is much more than a pass to beautiful places: every penny you spend helps keep these places alive and special for the future, and open to all."