The UN has a recommendation for refugee camps that might surprise you

With a record 69 million people driven from their homes by war and persecution, the United Nations on Wednesday urged countries hosting large numbers of refugees to plant more trees as deforestation risks denuding landscapes and triggering conflict.

Four out of five people who flee their homes rely on firewood for cooking and heating, which is a major cause of deforestation in surrounding areas, said the U.N. refugee agency (UNHCR) and the Food and Agriculture Organization (FAO).

"Basically we need more energy sources," said Andrea Dekrout, a Geneva-based environmental expert with UNHCR.

"In certain cases, forestry can meet that end," she said, adding that the U.N. is also trialling the use of cooking gas as an alternative fuel in Tanzania and Bangladesh.

Humanitarians, refugee-hosting countries and businesses plan to sign a global action plan in July to provide all displaced people with access to sustainable energy by 2030, in line with global development goals.

The two U.N. agencies published a manual on Wednesday advising governments and humanitarians to plant fast-growing trees for energy, food and fodder in areas hosting large numbers of displaced people to reduce tree loss and conflicts.

"It seems like a simple thing to plant a tree," Dekrout told the Thomson Reuters Foundation. "But it has to be the right kind of tree, in the right place and planted the right way. It has to first survive and later, produce."

Uganda and Bangladesh are two priority countries, on the frontline of Africa and Asia's largest refugee crises and host to more than 2 million uprooted people, mostly from South Sudan and Myanmar.

Conflicts in these two countries were major drivers of displacement in 2017, which saw the biggest increase in the global number of refugees in a single year.

In Uganda's Bidibidi refugee camp, each household uses about 20 kg of wood per day, the U.N. found in a 2017 survey, predicting that all the surrounding trees would be felled within three years if alternatives were not found.

Arturo Gianvenuti, a forestry specialist with the FAO said plans have been developed to create dedicated plantations in Uganda to increase firewood supplies and promote the use of alternative energy.

In neighbouring Tanzania, UNHCR said trees nurseries have been started in camps hosting refugees fleeing the Democratic Republic of Congo and Burundi who have clashed with locals over firewood.

If deforestation around refugee camps is not addressed, degraded soils and water shortages could render local farmers and fishermen destitute and force more people to leave their homes, experts said.