Agroforestry For Biodiversity And Climate Resilience

by Nathan King

There is a paradigm shift toward farming with trees to meet climate neutrality and biodiversity goals. The European Commission plans significant funding for agroforestry farms under the Farm to Fork Strategy and the Biodiversity Strategy for 2030 [1, 2]. These are the how, where, and why of agroforestry: farming with trees. 

The Farm to Fork and Biodiversity Strategies for 2030 adopts agroforestry as a nature-based solution. Nature-based solutions help society towards socio-ecological goals, such as climate action and promoting life on land and below water [3]. 

Carbon-negative farming, wildlife corridors, flood mitigation, pest reduction, and erosion barriers are but a few of the benefits that make agroforestry farms more resilient [4]. Women and Indigenous peoples are more vulnerable than men to environmental degradation and natural disasters [5]. Therefore resilient farming systems such as agroforestry are vital for gender equality and cultural heritage. 

The European Green Deal promotes agroforestry systems as natural carbon sinks and biodiversity hotspots [1]. Another benefit of agroforestry is nutrient cycling. When nutrient cycling is managed with agroforestry, water quality improves and farmers rely less on chemical fertilizers, pesticides, and herbicides [6]. Just as there is a Water Framework Directive and Air Quality Directive in the EU, experts have called for a Nutrients Framework Directive in order to manage nutrient cycling in environmental systems [7]. Trees also produce useful household materials: wood fuel, fiber, animal fodder, compost, and timber. 

Carbon and agroforestry   

Agricultural practices such as land clearing are carbon intensive. Burning or decomposing vegetation releases stored carbon into the atmosphere. Tillage also emits carbon, because plant residues combined with oxygen decompose rapidly. Soil tillage affects two-thirds of arable land [8]. Clearing, planting, and harvesting farmland often requires heavy machines that burn fossil fuel. Agriculture is thus implicated in the climate crisis for its direct emissions tied to global warming. 

Trees absorb carbon dioxide during photosynthesis through their leaves. A large tree, therefore, stores several tons of CO₂ aboveground and belowground. Trees store carbon underground in their roots, and by exuding organic acid into the soil to extract soil nutrients and promote the growth of soil organisms [9]. Temperatures are more moderate in the shelter of trees, the ground is shaded, and livestock can graze under the trees, creating multiple economic uses for the land without increasing carbon emissions. 

Designing agroforestry systems according to location

Locations with shorter planting seasons benefit from cultivating rows of trees as windbreaks to shelter crops and wildlife (Image, top right) [9]. Home gardens need not be confined to a box; shade trees reduce daytime temperatures and reduce drought conditions (bottom right) [9]. Another way to grow food using agroforestry is to maintain an existing forest by selectively removing trees to plant crops (bottom left) or by raising animals in the forest (top left).

Figure 1. Agroforestry system configurations [9]. 

Nutrient conservation with agroforestry

In addition to yields, agriculture in the 2020s must provide ecosystem services such as adequate water filtration, wildlife habitat, carbon sequestration, and nutrient cycling [6]. There is a need to reverse biodiversity and carbon losses from unsustainable agricultural activities because farming affects 50% of the earth’s land area and only 38% remains for forests and 11% for shrubs and grassland [11]. 

Animals return 90% of the nutrients they consume [12]. Excess nutrients can negatively affect air, water, and soil resources. Agroforestry is a nature-based solution: trees absorb excess nutrients, aerate the ground for better infiltration, prevent odor drift, and shelter animals from harsh weather. Agroforestry such as forest farming and silvopasture combines layers of vegetation and minimizes disturbances so overall species counts are higher, weeds are suppressed, and crops are more resilient to airborne pests and diseases [6]. 

Ecosystem resilience with agroforestry

The advantages of continued land use for agroforestry are hosting biodiversity and cycling nutrients, as well as afforestation and land regeneration, so agroforestry is ideal for revegetating degraded land [12]. Carbon storage and biodiversity in agroforestry depend on species selection [13]; access to locally-adapted varieties will also be facilitated by the Farm to Fork Strategy. 

With the same principles of minimal disturbance, a forest can become an agroforestry farm by removing trees to grow crops on the fertile forest floor [10]. Global commodity crops such as coffee, tea, and cocoa grow in agroforestry systems, with reduced inputs and nutrient runoff compared to unshaded varieties [14]. Specialty crops and higher crop variety are possible in agroforestry designs, such as growing edible fungi in underutilized low-light places around the farm [15]. New and attractive employment opportunities are possible as well as ecotourism [6]. 

Temperate zones have different agroforestry designs than tropical and subtropical regions because there is less solar energy available for photosynthesis at more extreme latitudes. Tropical agroforestry systems have abundant solar energy and thus denser plantings, while temperate agroforestry could be organized in alleys, such as cropping cereals between walnut, chestnut, and hazelnut trees. Young trees grow rapidly in alleys, providing additional farm resources and habitat [12]. 

Agroforestry may be present on farms and in home gardens in your region; the following lists the extent of agroforestry types in European countries:

Table 1. Stratification of European agroforestry, Agroforestry in the European Union [6].

Conclusions

Farming activities affect half of the world’s land surface [11]; although most people live in urban areas, farming is a tradition in which every human is a stakeholder.  Despite the potential for carbon storage, farming, forestry, and land use are major sources of carbon emissions, responsible for 18% of global emissions [16].

With agroforestry, carbon emissions are decoupled from food yields because perennial crops conserve soil, water, animal fodder, fuel, fertilizer, and pest management resources. Expanding agroforestry systems will have further benefits, such as nutrient cycling, carbon storage, and increasing biodiversity. Agroforestry systems are nature-based solutions to some of society’s ecological problems. 

Funding agroforestry on a larger scale represents a paradigm shift in agricultural administration by the European Union toward conserving biodiversity and adopting carbon-negative farming routines. The policy shift recognizes that the climate crisis harms agricultural producers and consumers alike, while biodiversity loss further threatens ecosystems. In contrast, agroforestry facilitates healthy, productive ecosystems and responsible management of natural resources for the future.

References:

[1] Farm to Fork Strategy. https://food.ec.europa.eu/system/files/2020-05/f2f_action-plan_2020_strategy-info_en.pdf, accessed on 4.4.2023.
[2] EU Biodiversity Strategy for 2030. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex%3A52020DC0380, accessed on 4.4.2023.
[3] Sustainable development goal 15, Life on Land. https://www.un.org/sustainabledevelopment/biodiversity/, accessed on 4.5.2023.
[4] Nature-Based Solutions Resource Guide. https://www.whitehouse.gov/wp-content/uploads/2022/11/Nature-Based-Solutions-Resource-Guide-2022.pdf, accessed on 4.5.2023.
[5] Social issues and agroforestry solutions. https://www.fao.org/forestry/agroforestry/90000/en/, accessed on 4.4.2023.
[6] Augere-Granier, ML. Agroforestry in the European Union. European Parliament Briefing, https://www.europarl.europa.eu/RegData/etudes/BRIE/2020/651982/EPRS_BRI(2020)651982_EN.pdf,  accessed 16.02.2023.
[7] Wassen, M.J., Schrader, J., Eppinga, M.B., Sardans, J., Berendse, F., Beunen, R., Peñuelas, J. and Van Dijk, J., 2022. The EU needs a nutrient directive. Nature Reviews Earth & Environment, 3(5), pp.287-288.
[8] Tillage practices. https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Agri-environmental_indicator_-_tillage_practices, accessed on 5.4.2023.
[9] Fujii, K. and Hayakawa, C., 2021. Root exudation and biodegradation of organic acids in a tropical forest soil under dipterocarp and pioneer trees. Plant and Soil, 469, pp.213-226.
[10] Brick, E.S.R., Holland, J., Anagnostou, D.E., Brown, K. and Desmulliez, M.P., 2022. A review of agroforestry, precision agriculture, and precision livestock farming—The case for a data-driven agroforestry strategy. Frontiers in Sensors, 3, p.998928. https://www.frontiersin.org/files/Articles/998928/fsens-03-998928-HTML/image_m/fsens-03-998928-g002.jpg. Accessed 20.02.2023.
[11] Ritchie H and Roser M, https://ourworldindata.org/land-use, accessed 21.02.2023. 
[12] Agroforestry from Paradigmshiftfilm Sweden (2020) Agroforestry in Europe – with Philipp Weiss, Martin Wolfe, Martin Crawford, Johanna Björklund. Available at: https://youtu.be/n4T3MiA7p_0, accessed 14.02.2023.
[13] Celentano et al., Carbon sequestration and nutrient cycling in agroforestry systems on degraded soils of Eastern Amazon, Brazil, accessed 14.2.2023.
[14] de Sousa, K., van Zonneveld, M., Holmgren, M., Kindt, R. and Ordoñez, J.C., 2019. The future of coffee and cocoa agroforestry in a warmer Mesoamerica. Scientific Reports, 9(1), p.8828.
[15] Bruhn, JN, Woodland specialty mushrooms: Who grows them and what are the problems? https://www.fungifun.org/docs/mushrooms/scef2000/scef535%20Woodland%20specialty%20mushrooms%20Who%20grows%20them%20and%20what%20are%20the%20problems.pdf. Accessed 20.02.2023.
[16] Ritchie H and Roser M, https://ourworldindata.org/emissions-by-sector#agriculture-forestry-and-land-use-18-4, accessed 3.5.2023.

Additional links: 

Wakelyns Organic Agroforestry, Suffolk, UK (wakelyns on Instagram)
Agrosintropia (YouTube and Instagram)
Ecoar Agrofloresta (Instagram)
Regen. Agroforestry Podcast (regenerativeagroforestry on Instagram)
University of Missouri’s Center for Agroforestry (mizzouagroforestry on Instagram)
European agroforestry locator: https://www.agforward.eu/map-of-agroforestry-research-and-demonstration-in-europe.html