Effective and enthusiastic
Soli&Green, founded by a handful of environmental activists in their thirties, organises planting weekends in winter and helps other organisations that want to do the same.
Since November, it has compiled a list of all the country's reforestation initiatives and estimates that by mid-January, almost a million trees had been planted.
The state does most of the work. The regional commission for agricultural development (CRDA), a public body, provides volunteers with basic training, thousands of tree shoots and a watering truck.
"When we use labourers, we plant around 1,000 trees a day. But with volunteers, we can plant 4,000, even 5,000 a day. There are a lot of them, they are effective and it's free," says Nizar Khlif, a manager at the Siliana branch of the CRDA.
"And there is a participatory approach - they involve the local population."
The arrival of the city-dwelling, backpack-carrying volunteers has inspired Siliana residents.
In 2017, 40 hectares of forest went up in smoke. A suspected arsonist said he had hoped the blaze would compel authorities to recruit forest rangers, and that he would be hired.
"It was as if we'd lost a family member," says 14 year old Khairi Jaied, from a nearby village. "I have many good memories of the forest. It's good to see these people helping so that our region can rebuild its resources."
But the state is increasingly joining forces with local residents and its reforestation strategies seem to be paying off.
Forests and scrubland now cover more than 1.3mn hectares, or around 8.5 per cent of the country, up from 7.4 per cent in 2011, according to the directorate general for forests.
The aim is to reach ten per cent by 2024.
Whether it's post-fire reforestation or fighting desertification in the south by planting palms and olive trees, the task is enormous.
Nessim Zouaoui, 26, says he is sometimes discouraged.
"I spend most of my free time cleaning beaches and planting trees," says the young entrepreneur and activist.
"But we just went to see a neighbouring plot where we worked in March and we realised that we had completely planted a forest. That's really motivating!"
Volunteers plant trees on the Kesra mountains in Tunisia's Siliana region on November 14, 2019