Image copyright PJ Stephenson Image caption The study calculates that almost one-in-six people depend on forests for food and income

Forests can play a vital role in supplementing global food and nutrition security but this role is currently being overlooked, a report suggests.

The study says that tree-based farming provides resilience against extreme weather events, which can wipe out traditional food crops.

It warns that policies focusing on traditional agriculture often overlook the role forest farming could play.

The findings were presented at the UN Forum on Forests in New York, US.

The report is the result of a collaboration of more than 60 leading scientists, co-ordinated by the International Union of Forest Research Organisations (IUFRO) on behalf of the Collaborative Partnership on Forests (CPF).

"The report is not trying to suggest that people should start relying on forests more than conventional agriculture," explained Bhaskar Vira, the chair of the panel which compiled the report.

"It is very much about the complementary roles that forests can play alongside conventional agriculture.

"The evidence shows that a large number of people still rely on the food from forests and trees to supplement their diet," Dr Vira, director of the University of Cambridge Conservation Research Institute.

Branching out

Global estimates suggest that one-in-nine people are still suffering from hunger, and the majority of them are in Africa and Asia.

Image copyright T.SUNDERLAND Image caption The role of trees and forests in food security is often overlooked by policymakers

The report highlights a range of measures that offer "great potential" to improve food security and improve people's quality of life.

It calculates that almost one-in-six people directly depend on forests for their food and income. It adds that in the Sahel region of Africa, tree-related production contributes an average of 80% to household incomes, particularly from shea nut production.

The report also highlights the importance of forests as a source of firewood and charcoal, essential to enable people to consume the calories found in conventional food crops. Globally, an estimated 2.4bn people use this renewable fuel source for heating and cooking.

More than wood

The authors also emphasise links between forests and conventional farming. For example, forests are a crucial habitat for key pollinators of many food crops. Without forests, the vital ecosystem service provided by birds and insects would be diminished, resulting in increased food security concerns.

"This report reminds us of the vital role of forests in building food security," observed Thomas Gass, assistant secretary-general for policy in the UN Department for Economic and Social Affairs.

"It makes a convincing case for multi-functional and integrated landscape approaches, and for community-level engagement to re-imagine forestry and agriculture systems."

Another benefit lies in forests' ability to add diversity to the food production system, explained Christoph Wildburger, co-ordinator of the IUFRO Global Forest Expert Panels.

"Large-scale crop production is highly vulnerable to extreme weather events," he said.

"We know that forests already play a key role in mitigating the effects of climate change. This report makes it very clear that they also play a key role in alleviating hunger and improving nutrition."

Image copyright M.KLEINE Image caption Forest fruits provide valuable sources of income as well as nutrition for millions of people

Dr Vira added: "What we are saying to policymakers is to start thinking more about the landscape as an integrated production system rather than the current and conventional view that often places agriculture and forestry in opposition to each other.

"We make a really strong case for thinking about the landscape holistically."

Late last year, the Global Nutrition Report warned that most countries in the world faced a serious public health problem as a result of malnutrition.

It said that every nation except China had crossed a "malnutrition red line", suffering from too much or too little nutrition.

According to that report, malnutrition led to 11% of global GDP being "squandered as a result of lives lost, less learning, less earning and days lost to illness".

Dr Vira told BBC News: "One really important insight we got was that conventional agriculture was good for the calorific intake but not so good when you started to think about healthy and balanced diets.

"When we talk about food security we need to stop focusing simply on calories. It is hugely important to recognise how much of a balanced diet comes from outside of conventional agriculture, particularly from trees and forests.

"Forests matter when it comes to human wellbeing."