A woman displays items regularly foraged and cultivated in the forest at a food fair in Luwingu, Zambia. CIFOR/Joe Nkadaani

Forests and trees make an important contribution to human diets in rural areas of the developing world. They provide essential nutrients from vegetables, fruit and nuts and are a source of wild meat, boosting the range of foods that support the health and wellbeing of society, particularly children.

However, at least 2 billion people – more than 30 percent of the world’s population – suffer from vitamin and mineral deficiencies, also known as “hidden hunger.”

In resource-poor countries, in particular, iron deficiency is a major health issue that can cause anaemia, while vitamin B12, zinc, folate and vitamin A are also lacking in many people’s diets. The consumption of processed foods high in salt, saturated fats and sugar only exacerbates undernourishment and obesity around the world, leading to chronic illness or preventable death in some cases.

To address these concerns, the United Nations aims to end malnutrition by 2030, as outlined in its Zero Hunger targets under the Sustainable Development Goals.

Current policy approaches to feeding the world’s growing population focus on agriculture, livestock and fisheries, with an emphasis on increasing yields of staple crops. However, a recent paper sponsored by the Center for International Forestry Research (CIFOR) and the U.S. Agency for International Development demonstrates how diet and nutrition can benefit from a broader landscape perspective that not only addresses agriculture but also integrates forest conservation and restoration.

This can be achieved by using nutritional and dietary guidelines as the foundation for strategic development of integrated mosaic landscapes.

An understanding of the relationship between diet and landscapes can be further improved through multidisciplinary research at universities, focusing on how to sustainably meet food security and nutrition goals, according to the authors.

Their work resulted from a collaboration among 14 scientists from universities and research centers around the world as part of a working group on “Food and Landscape Diversity” funded by the U.S. National Socio-Environmental Synthesis Center (SESYNC).

“Giving consumers the opportunity to eat a diverse, healthy range of foods requires us to look beyond the farm,” says Sarah Gergel, a professor of landscape ecology and conservation at Canada’s University of British Columbia and the paper’s lead author. “Universities have an important role to play in meeting this challenge. We must do more than train scientists in agriculture or forest management, but rather train scholars to better understand the intersection of these disciplines.”

Tree cover in tropical regions has been linked to dietary quality and diversity in numerous studies.

Children, in particular, gain nutritional benefits from forested areas surrounding their communities and have access to fewer food sources when adjacent forest is lost. These landscapes contribute to nutritional diversity in four ways: the direct pathway (wild meat and forest-sourced foods); the agroecological pathway (soil fertility, pollination, pest control and other ecosystem services that support agricultural production); the energy pathway (fuelwood and dung for cooking); and the income pathway (forest products provide livelihoods for rural families), the authors said.

Diverse landscapes – with both farm fields and forests – can offer a range of nutritional functions. Disturbed and secondary forests provide wild foods that are often unavailable in primary forests. Forest edge habitats may feature a higher number of animal and plant species, including nutritional fruits such as guava, while serving as convenient entry points for hunting. Agro-biodiverse small agricultural plots can hold more nutrient-rich produce than larger specialized fields and are the source of most food in sub-Saharan Africa, Southeast Asia, South Asia and China. Rec­ognizing the role of different landscapes could help integrate the various aspects of forests, trees and farms capable of supporting diverse diets, according to the paper.

“Diverse landscapes with trees and forests provide habitat for a variety of wildlife species, including pollinators that aid agriculture,” Gergel says. “Forests near streams also help keep pollutants out of rivers and waterways. These other forest benefits can then feed back and further support human health and nutrition.”

The nexus between forests and diet is complex and requires a deeper understanding of food origin and seasonal variation. Fruit, vegetables or meat purchased in a market, for example, often have an indeterminate origin, whether it be an adjacent forest, a farmer’s field or even another country. This lack of information hinders efforts to identify the contribution that landscapes make to nutrition. Similarly, seasonality affects the availability and consumption of forest foods, presenting knowledge gaps for dietary intake assessments. Thus, enhanced diet diversity metrics are also needed to capture the nutritional contributions from entire landscapes, according to the paper.

From a technology perspective, the authors recommend the use of high spatial resolution imagery from satellites to improve the monitoring and mapping of forests and trees to better characterize landscape diversity. Detailed tracking of even small patches of fruit-bearing trees, for example, could assist nutritional planning. Tracking small remnant forest patches is helpful in guiding conservation and restoration initiatives, which can occur within the same landscapes where food security is of concern.

“The incredible advances in high resolution satellite imagery will revolutionize how we understand forests and their role in nutrition,” Gergel says. “Individual fruit trees, which are an important source of vitamin A, can be mapped from space. And the timing of vegetation ‘green-up’ and drought can be tracked with increasing levels of detail, helping us understand seasonal changes in the forest foods likely to be available on the ground.”

Forest landscapes can play a more prominent role in the fight against “hidden hunger” if they are integrated into poverty alleviation and nutrition strategies. Biodiversity conservation, climate change, land-use change, agriculture, human health and nutrition are all affected by landscape diversity. By recognizing these competing demands, policy makers can adopt food security and nutrition approaches that have more impact in the developing world, Gergel added.