Trees: a pairing for coffee, chocolate and wine
Favourite foods need agroforestry to survive
This article is part of a Landscape Newsseries on agroforestry, published in partnership with World Agroforestry (ICRAF) in conjunction with the 4th World Congress on Agroforestry.
By Gabrielle Lipton
In Burkina Faso, drought pockets are increasing. The rainy season doesn’t come on time anymore and months of the year will pass with hardly a drop of rain.
But in the midst of this, the Guié agroforestry farm recalls a landscape out of Europe, with hedges and fields and meadows still growing and blooming beneath the ever-stronger sun. With the help of trees, this area is now well adapted to climate change, able to retain rainwater for long periods, lessening the need for irrigation and increasing crop yields.
‘Trees are complementary [to agriculture] and absolutely have to be included as part of farming’, said Seydou Kaboré, manager of the farm, at the 4th World Congress on Agroforestry in Montpellier, France, in May. ‘We won’t consider farming without trees’.
It’s no secret that climate change is affecting food systems. According to a 2017 study, wheat productivity has stagnated after tripling during 1900–1990, due directly to climate change. What’s more, scientists have proven that carbon dioxide and nutrition levels in staple grains have an inverse relationship; as the former goes up, the latter declines.
As climate change has progressed, commercial farming has seen trees disappear from agricultural landscapes in lieu of crops planted to their maximum capacity. But, increasingly, research is proving the deleterious effects of monocultural farming on soil health, the nutritional and marketable value of crops, and the exposure of crops to pests, diseases and increasingly erratic weather.
There’s no doubt that food must be produced en masseto feed the growing global population. And yet, more and more, small-scale family-farming practices — which often include trees — are increasing in popularity throughout the world. Although this sounds counterintuitive, such agroforestry practices, when enlarged to commercial scale, are proving they can provide sustainable and healthy food supply.
Take, for example, French wine. Its packaging and reputation increasingly bely the difficulties that go into its making due to climate change. In the South of France, when unusual amounts of frost covered vineyards in 2017, helicopters were flown in to push warm air down onto the vines to keep them alive. During summer droughts, vineyards have gone up in flames. And even when there aren’t weather disasters, harvests have begun earlier and earlier owing to seasonal shifts, leading to a lower quality of wine because the grapes’ chemical compounds don’t have adequate time to accumulate.
Marie Gosme of the French National Institute for Agricultural Research has advocated for incorporating agroforestry into the region’s famous vineyards, supported by scientific research. She’s found that trees can reduce radiative cooling at night, which decreases the risk from frost, and their shade during daytime can mitigate harsh temperatures.
Collecting data in 2015, she found that vines close to trees were negatively impacted, with reduced photosynthesis and competition for nitrogen in the soil. But, on the whole, the benefits were greater: no water competition between the vines and the trees and better overall vine growth as measured by number of shoots from the vines, number of grape bunches per vine, weight of each bunch and total grape harvest per vine.
Similarly, in Ethiopia, climate change has been hitting the coffee industry — the largest in Africa — hard. Led by Ethiopian plant scientist, Tesfay Gidey, new research modelled the impact of climate change on coffee yields in agroforested Ethiopian landscapes, compared to monoculture, for the next 40 years. The results showed that yields could be reduced by up to 60% in the latter and only up to 25% in the former.
‘It can be concluded that coffee production under agroforestry systems has a higher level of resilience when facing future climate change’, states the study.
Changes in temperature and rainfall are also threatening the future of cocoa. While predictions published last year by the US National Oceanic and Atmospheric Administration said that cocoa could be nearly extinct by 2050, Kira A. Borden, a scientist at the University of British Columbia, says that these judgements are based on the status quo without taking into account what could happen under different management conditions, such as agroforestry, which can dramatically improve the sustainability of the crop.
In her research on cocoa in Ghana — which together with Côte d’Ivoire produces half of the world’s chocolate supply — Borden took individual root samples to learn how the trees were working with cocoa plants. She compared sites in optimal and suboptimal precipitation conditions, sandy and loam soils, and under full sun or shade. In order to determine what was working and what wasn’t, she and her team manually excavated lateral root systems, looking at responsiveness to water and nutrients. They found that in different environments, cocoa plants of the same variety and age were acquiring their food and water in different ways. Shade, interestingly, only had an impact in suboptimal environments.
In Côte d’Ivoire, ICRAF scientist Aster Gebrekirstos has been examining why and how cocoa swollen shoot virus disease (CSSVD) in conjunction with climate change has been affecting production. Through looking at the growth histories of trees with and without symptoms of the virus, she is mapping how climate change and stressful events such as CCSVD affect different cocoa varieties.
‘I found that cocoa is responding to climate variability and trees have been attacked by multiple pathogens with differences in varieties and sites’, she said, noting that deforestation is further spurring problems and that agroforestry can help ecological conditions be more sustainable. ‘The study is ongoing but soon we will recommend which cocoa variety to grow where’.
This is all to say that agroforestry is not as simple as just plant trees.The level of specificity needed for tree incorporation to work well is high, with water, soil and biodiversity conditions all coming into play, as well as the skill level and know-how of farmers to care for a variety of species.
To this end, in 2017, a map was published depicting which tree species could thrive in different areas across Central America. Roeland Kindt, a senior ecologist at World Agroforestry (ICRAF), who published, Suitability of Key Central American Agroforestry Species under Future Climates: an Atlas, is now working on a similar atlas for Africa, with an even higher level of detail. Using more than 25 different algorithms, he’s able to depict models of how to distribute more than 150 tree species across different landscapes.
The next step is to incorporate his findings with future climate projections, to map how species could be distributed in the future. The second phase of the atlas will be verified for accuracy by botanists but he notes that as the climate changes, the atlas will have to, too.
‘It’s my dream that this will become an interactive project’, he says, hoping that it will be continually updated with the help of citizens and scientists to and help keep foods alive and well.
World Agroforestry (ICRAF) is a centre of science and development excellence that harnesses the benefits of trees for people and the environment. Leveraging the world’s largest repository of agroforestry science and information, we develop knowledge practices, from farmers’ fields to the global sphere, to ensure food security and environmental sustainability. ICRAF is one of the 15 members of the CGIAR, a global research partnership for a food-secure future. We thank all donors who support research in development through their contributions to the CGIAR Fund.