Until I learned of their prognosis, I was one of the four in five people who could not identify an ash tree. Now I see them everywhere. I have opened my curtains to a sprawling ash every morning for years; all day long I overlook a straggly individual from my desk. Both are healthy, but I’ve added them to the list of things to worry about.

A child hoisted a Tunisian flag up a pole beside a palm tree in the concrete courtyard of her school in Tunis. The national anthem blared and gardening gloves were handed out to the watching crowd of environmentalists, local politicians and call-centre employees, who were on a corporate responsibility outing and wearing matching T-shirts printed for the occasion. The Eid al Shajara (‘tree festival’) has taken place annually on the second Sunday in November since 1958. Tunisia’s first president, Habib Bourguiba, said he wanted to ‘awaken in the nation a lively interest for trees, an appreciation for their aesthetic and economic value’.