In recent weeks, Paul Redman has ended his workday by donning walking shoes and traversing the entire breadth of Longwood Gardens, the grand assemblage of conservatories, fountain terraces and gardens in the former du Pont estate in southeastern Pennsylvania.

For Redman, the botanical garden’s chief executive, the daily walks have brought home the two paradoxical realities of the past few weeks: the beauty of the Mid-Atlantic spring in a highly cultivated setting, and the total absence of visitors to soak it in.

The earliest fossilised trees, dating back 386 million years, have been found at an abandoned quarry in New York.

Scientists believe the forest they belonged to was so vast it originally stretched beyond Pennsylvania.

This discovery in Cairo, New York, is thought to be two or three million years older than what was previously the world's oldest forest at Gilboa, also in New York State.

The findings throw new light on the evolution of trees.

What did they find?

The Blue Mountains Botanic Garden is one of the properties ravaged by the fire, with staff on Monday morning confirming that damage to parts of the garden is “significant.”

The gardens are closed due to the fires and staff say they are still assessing the full extent of the damage.

“Thankfully, most of the Garden’s Living Collection along with the main buildings are safe at the moment,” staff said.

The garden will remain closed for at least another week, according to staff.