A review of the carbon sequestration potential of fruit trees and their implications for climate change mitigation: The case of Ethiopia

Abstract

Carbon sequestration is defined as the process of capturing and storing atmospheric carbon dioxide. Fruit crops are indispensable both for climate change mitigation and ensuring food security. However, the impact of fruit trees is not adequately investigated. This review assesses the carbon sequestration potential of fruit trees and their implications for climate change mitigation. Fruit trees use photosynthesis to absorb CO₂ from the atmosphere and assimilate it into their cellulose, lowering atmospheric buildup. Horn of Africa is the most vulnerable region for climate change, and Ethiopia is also facing unpredictable weather, which brings sporadic floods and droughts that harm the agricultural sectors. Dramatic rise of CO₂ from 280 ppm in 1850 to 420.2 ± 0.5 ppm in 2023 is reported to link with human activity. In most Ethiopian farms, multipurpose fruit trees are rarely cultivated, and the only experience is planting trees in the homestead areas. Even though fruit trees have an enormous potential to store carbon, the destruction of those trees is also results greenhouse gas. Tree plants, including fruit trees, are thought to absorb 0.42 to 0.65 pentagrams of carbon per year. Above- and below-ground biomasses have been described to sink more than 40% of carbon. Agroforestry practices should adopt all fruit species on the basis of carbon sequestration and climate change mitigation in their growing stratum. Therefore, in order to oblige countries to adopt versatile fruit trees to meet food and nutrition security, carbon sequestration, and climate change mitigation efforts should have both political and economic sustainability.

Keywords:

• carbon pools
• carbon sequestration
• litter biomass
• soil carbon
• store carbon

PUBLIC INTEREST STATEMENT

Carbon sequestration is defined as the course of apprehending and storing atmospheric carbon-dioxide and it is an effective method to reduce the atmospheric carbon-dioxide. Climate change is a pressing issue in Ethiopia exacerbated by human activities such as fossil fuel consumption and deforestation. In Ethiopia, climate variability is highly affecting the environmental settings and causing for soil erosion, drought, desertification, biodiversity loss, flooding, and water pollution, and health risks. Multipurpose fruit trees are an important carbon pool used to store large amounts of carbon in their biomass (above and below ground biomass). Globally, versatile fruit trees are extensively used to sequester carbon from the atmosphere. In general, in addition to the forest trees, cultivation of multipurpose fruits is paramount to protect our environment. Therefore, fruits selection on the basis on their nutrition composition and role of carbon sequestration is imperative for the nations such as Ethiopia.

1. Introduction

Nowadays, carbon dioxide (CO₂) emissions and climate change are global concerns. Moreover, global warming, which is a result of human activity, is the most feared concern of the new millennium (Abbass et al., 2022). Climate change is a pressing issue exacerbated by human activities like high fossil fuel consumption and deforestation, which contribute to the loss of biodiversity (Shivanna, 2022). Carbon is a crucial life component found in plant biomass, soil, geological deposits, atmosphere, and seawater in dissolved forms (Patil & Kumar, 2017). Since the level of carbon dioxide increased from 280 parts per million (ppm) in 1850 to 420.2 ± 0.5 ppm in 2023, a number of factors are stated by different scholars for this increment (Godard, 2017). In Ethiopia, carbon emissions for 2020 were 18,098.00 with 2.2% increment from 2019. While in 2019, 17708.00 were reported with 3.99% rise from 2018. Similarly, carbon emissions for 2018 were about 17,028.40 with 7.22% increment from 2017. Correspondingly, carbon emissions for 2017 were nearly 16,000.00 and 4.17% increments from 2016 were also reported (Hundie, 2021). In general, a total of 3.3 billion tons of carbon per year is reported to be added in to the atmosphere (Ukpanyang & Terrados-Cepeda, 2022). The consumption of solid, liquid, and gas fuels are reported to contribute to carbon dioxide emissions, which are produced during the burning of fossil fuels and the production of cement (Friedlingstein et al., 2022).

The process of carbon sequestration includes CO₂ absorption from the atmosphere and storing it as carbon in biomass such as tree trunks, branches, foliage, roots, and soils (Hurd et al., 2022).

A number of factors, such as tree age, leaf area, and photosynthetic efficiency are reported to affect the carbon capturing process during photosynthesis (Wang et al., 2023). The major quantities of carbon are reported to be stored in above- and below-ground biomass, dead wood, litter, and soil organic matters (Dibaba et al., 2019). Moreover, the amount of carbon that trees store depends on their age, species, soil type, climate, terrain, and management practices (Vacek et al., 2023). For instance, the rate of carbon storage is reported to rise in young trees, but it decreases after reaching the maximum size (Harris & Betts, 2023).

Fruit trees are stated to contribute significantly to the reduction of atmospheric carbon dioxide through carbon sequestration (DiMatteo et al., 2023). Because due to their structural differences from annual crops, fruit trees are told to absorb considerable quantities of atmospheric carbon (Song et al., 2023). Trees and grasslands sink atmospheric carbon; whereas agricultural practices (ploughing, cultivation, etc.) generate greenhouse gases (Zhan et al., 2023). Therefore, it’s vital to use good farming techniques that can lessen emissions through increasing the biosphere’s capacity to store carbon (Lal, 2023). In addition, replacement vegetation on cleared land is also reported to sequester carbon. On the other hand, plants store carbon in the soil where it can be used as soil organic carbon (SOC) through photosynthesis.

Irrespective of the potentiality of fruit crops, large numbers of smallholder farmers in Ethiopia are facing many challenges including awareness gaps, lack of improved varieties, soil depletion, variable weather conditions, pest and disease problems, weak market system, and lack of postharvest facilities, unreliable rainfall, low price, high input costs, low incentives, low output, insufficient extension services, low labour productivity, poor infrastructure and poor harvest management systems. In addition, insufficient researches and documentation on carbon sequestration potential of fruit trees are also the major hindrances affecting fruits cultivation in Ethiopia. Thus, this review aims to assess the carbon sequestration potential of fruit trees and their implications for climate change mitigation.

2. Methodology

During the literature review, the authors used various strategies. Reputable journals from the Scopus, Web of Science, and PubMed databases were used for the compilation of this review. The inclusion criteria primarily focused on articles published after 2019, except for relevant facts and books.

3. Global climate change

Agriculture is one of the key sectors in Africa and is critical to the continent’s growth. It is identified to employ over 65% of the labour force and contributes to 32% of gross domestic production (GDP) (Osabohien et al., 2019). However, Africa continent in general and the Horn in particular is the most at risk from climate change (Sharmake et al., 2023). Frequently, in the Horn of Africa, unpredictable weather affects agricultural production through bringing drought and sporadic floods (Tirado et al., 2015). Africa’s agriculture is therefore anticipated to be mostly vulnerable given that the continent already experiences high temperatures and diminutive precipitation (Davis, 2023). By the 2060s and 2090s, the region’s mean annual temperature is predicted to rise by 1.1 to 3.1°C and 1.5 to 5.1°C respectively (Mengesha Tadesse, 2023). These massive escalations are estimated to cause droughts and floods as well as steady degradation of the natural resources (Dongmo, 2022).

Apart from presenting additional complications, climate change poses a risk to realizing development and poverty reduction goals (Meyfroidt et al., 2022). Hence, the consequences of climate change could be quite severe because 80% of the world’s population relies on weather-dependent agriculture and the majority of which is small-scale farming or pastoralists (Bogale & Erena, 2022). Furthermore, extreme climate variation may disturb environmental settings and may cause soil erosion, deforestation, drought, overgrazing, desertification, biodiversity loss, flooding, and water pollution, food insecurity, energy shortage, and health threat (Oljirra, 2019). Thus, the people who depend on the environment, mostly the poorest and marginalized societies, will inevitably be the ones who suffer severely in effect of the climate change (Wassie, 2020). Correspondingly, the impacts on agricultural production, food security, and water availability are the common challenges of climate change in Ethiopia (Bogale & Erena, 2022).

Although fruit trees are reported to sink carbon, the attention for this approach is very low in developing countries including Ethiopia (Chakravarty et al., 2019). For example, apple trees intercropping with rajmash and oats were stated to store the highest ecosystem carbon, and 1.5–2 times higher than other cultivated crops (Zahoor et al., 2021). Moreover, fruit orchards and vineyards are told to acculumalate a substantial amounts of carbon by their structures (Sharma et al., 2021a). Thus, orchard management can enhance carbon pools in biomass and soil, but forest trees are chiefly considered for carbon trading and ecological amenities (Guidi Nissim et al., 2023). This could be partly explained by the lack of studies on the carbon storage capacity of various fruit trees (Plénet et al., 2022). Due to the expansion of agriculture in the tropical regions, forest resources are highly threatened. So, if fruit orchards are properly managed, they are reported to contribute a lot for sustainable development (Altieri & Koohafkan, 2008).

Just like forest trees, planting fruit trees in homesteads and other agricultural fields are indicated to improve the carbon sink (Jerikias & Zakio, 2022). In Ethiopia, most of the fruit trees are cultivated around the homesteads because they are important sources of food and income mainly in rural areas (Sinare et al., 2022). Fruit trees are described to use CO₂ as an input for the photosynthesis process and it is absorbed from the atmosphere and assimilate it into their cellulose and lowering atmospheric accumulation (Gressel, 2008). Thus, to take use of their capacity for carbon sequestration, several fruit trees with adaptive species and cultivars might be chosen (Zsögön et al., 2022). Fruit trees on homesteads are reported larger than those in normal fruit orchards because they are not properly managed and hence pruning the trees could offer farmers with wood biomass energy (Lyashenko et al., 2022).

According to a study done on biological carbon sequestration through fruit crops (perennial crops natural “sponges” for absorbing carbon dioxide from atmosphere), CO₂ is a major contributor to the greenhouse effect and can be naturally removed from the atmosphere by storing it in the biosphere (Patil & Kumar, 2017). In addition, mango trees had also special microclimatic conditions appeared to favor waste photodegradation, and thus eliminating the nutrients that were not incorporated into the soil (Reyes-Martín et al., 2021). For instance, the carbon pool of fruit trees is presented with a model example of an apple tree in Figure 1.

Figure 1. Typical representation of an apple tree along with a schematic depiction of carbon pools.

Source (Lakso et al., 1999).

According to a study conducted at Indonesia’s Purwodadi Botanic Garden in 2022 to estimate the carbon stock of numerous local fruit species collections, the majority of the indigenous fruit trees examined are potential carbon sink and should be encouraged in restoration programmes to reduce climate change (Yulistyarini & Hadiah, 2022).

A study conducted on the carbon sequestration potential of mango orchards in the tropical hot and humid climate of Konkan region, India, stated that polyembryonic seedling-grown mangoes have very high carbon sequestration potential than the grafted mangoes (Ganeshamurthy et al., 2019).

Furthermore, a survey done on the carbon sequestration potential of orchards and vineyards in Italy indicated that strong fruit tree ecosystems have positive net ecosystem productivity and net ecosystem carbon balance (Scandellari et al., 2016).

Moreover, a research conducted to evaluate the contribution of Tropical Fruit Plants and Soil Properties to the potential of Carbon Sequestration in Open Land Utilization for Mixed Plantations showed that there is a connection between soil properties and soil organic carbon, with low N-total content resulting in low soil organic carbon (Oviantari et al., 2021).

Similarly, a study done on the carbon sequestration potential of agroforestry systems in degraded landscapes in West Java, Indonesia, indicated that carbon stock variance is correlated with species density and variety (Siarudin et al., 2021).

On the other hand, research conducted on the management of soil organic matter and carbon storage in tropical fruit crops in Brazil stated that converting native forest to fruit crops reduced soil organic matter content and quality, impacting carbon dynamics and agricultural soil stocks (Guimarães et al., 2014).

According to a research done on fruit-based systems: a feasible alternative for carbon sequestration, fruit trees may grow for years and continue to store carbon as they increase biomass (Tesfay et al., 2022).

Assessment studies conducted on the appraisal of carbon capture, storage, and utilization through fruit crops in India indicated that the carbon storage potential of fruit trees may vary based on growth, development, and environmental conditions (Sharma et al., 2021b).

A field modelling study carried out to understand the carbon sequestration by fruit trees in apple orchards in Changping District, Beijing-China reported that carbon emissions resulting from management practices would not be offset through carbon storage in apple trees before they reached the mature stage (Wu et al., 2012). Consequently, in addition to producing apples and providing fruits, apple production systems could be assumed as carbon sinks when fruit production is excluded (Figure 1). According to a report from the United Nations Environment foresight013-brief, “Early warning, Emerging issues and futures,” It is significant that soil, through the oxidation of soil carbon contributes to climate change (Momani & Alzaghal, 2009).

A study done on carbon sequestration potential of tree crop plantations: Mitigation and Adaptation Strategies for Global Change in Denmark have shown that tree crop plantations can sequester carbon more effectively on low-carbon land (Kongsager et al., 2013).

According to a study done to assess the growth, carbon stock, and sequestration potential of oil palm plantations in Mizoram, Northeast India, there is significant carbon storage in oil palm plantations, with higher values than shifting agriculture fallows (Singh et al., 2018).

Similarly, research was done to evaluate the role of citrus orchards in reducing climate change through carbon sequestration in Pakistan’s Sargodha District in 2021, measuring carbon with straightforward methods can yield reliable results that increase the participation of developing countries in various payment initiatives like REDD⁺ (Yasin et al., 2021).

Correspondingly, according to the case study report from Htee Pu Climate Smart Village on the financial and environmental benefits of fruit trees in Myanmar’s central dry zone, there is an increase in interest worldwide in ecosystem restoration and rehabilitation of damaged landscapes (Manilay et al., 2021). Climate-Smart Agriculture can be used as a strategy by agricultural and development organizations to address degradation on small farms and related landscapes. On the other hand, carbon investors are reported to depend on farmer preferences (Roshetko et al., 2002). Comparatively, fruit trees and other crops often have lower carbon footprint value than animal products (Table 1).

Table 1. The average carbon footprint values of a few fruits cultivated worldwide

Type of fruits	Mean value of carbon concentration	References
Papaya	0.3kg (0.67lb) of CO2e/kg	Choinova (2023) Choinova (2023) Choinova (2023)
Jack fruit	0.9 kg CO2e/kg
Guava	0.15 kg CO2e/kg
Passion fruit	0.77 kg CO2e/kg
Dragon fruit	0.9 kg CO2e/kg
Banana	0.21 kg (0.48 lb)/kg
Mango	0.21 kg (0.46 lbs) CO2e/kg
Avocado	0.19 kg CO2e/kg
Pineapple	0.09 kg (0.20 lb) of CO2e/kg
Orange, Lemons and Limes	0.3kg (0.66 lbs) CO2e/kg
Apples	0.24 kg (0.53 lbs) CO2e/kg
Plum	0.4 kg (0.88 lbs) CO2e/kg
Peach	0.17kg (0.38lbs) CO2e/kg
Pomegranate	0.39kg (0.87lb) CO2e/kg
Cherry	0.584 kg CO2e/kg
Apricot	0.16kg (0.36lb) CO2e/kg
Kiwifruits	0.9 kg CO2e/kg
Grape	0.64 kg (1.42 lbs) CO2e/kg
Pear	0.34 kg CO2e/kg
Strawberry	0.39kg (0.88lb) CO2e/kg
Blueberries	0.45kg (1lb) of CO2e/kg
Raspberries (Aggregate fruit)	0.15kg (0.33lb) of CO2e/kg

4. The impact of climate change on food security

Climate change is reported to affect all pillars of the food security (Stavi et al., 2022). For example, in Ethiopia, climate change (external factors) is commonly mentioned to affect Ethiopia’s food security (Rahman et al., 2022). Globally, many research works are performed to evaluate the effects of climate change on agricultural production and food security of smallholder farmers (Wheeler & Von Braun, 2013). However, understanding about how anthropogenic climate change will affect local communities or individual households is somewhat limited. Because it is challenging to differentiate the effects of human interference and those of natural weather variations on climate change (Osberghaus & Fugger, 2022). Furthermore, it is difficult to anticipate both the potential good and negative effects as well as how they will all interact in different settings (Goswami et al., 2022). The National Adaptation Programme of Action in Ethiopia (NAPAE) highlights to accurately assess the impact of climate change across socio-economic sectors (Singh, 2020). Correspondingly, evaluating issues like crop consequences, productivity, carbon effects, socioeconomic changes, and technological advancements are remain challenging (Abbas, 2022). Climate change is reported to affect the growing seasons of agricultural crops (Thornton et al., 2014). Agricultural sector is the main source of income, hard currency, and food security of Ethiopia (Guyalo et al., 2022). Due to the dominance of small-scale farmers who mostly depend on rain-fed agriculture and traditional farming, Ethiopia is highly vulnerable to climate change and climate variability. According to Ethiopia’s regional vulnerability analysis, arid and semi-arid areas like Afar and Somali are sensitive to climate change (Bogale & Erena, 2022). Although Borena and Tigray regions experience good agricultural productivity in the highlands and midlands, persistent drought are affecting the lowland areas of the two regions (Deressa et al., 2008).

5. The role of fruit trees in mitigating climate change

5.1. Carbon pools in fruit tree ecosystems

5.1.1. Store carbon

Photosynthesis is the process by which trees absorb CO₂ from the atmosphere, mixing it with water and sunshine to produce glucose and oxygen (Manilay et al., 2021). Researchers stated that carbon is stored in the biomass of trees (above and below the ground) as well as in the soil organic matter beneath the canopy of trees (Vashum & Jayakumar, 2012). Numerous studies have shown that fruit plants, such as mango plantations in the Philippines, sequester CO₂ levels ranging from 47.66 to 62.33 tons/ha of CO₂ (Janiola & Marin, 2016). While Chavan and Rasal reported that the Philippines had a higher concentration of 206.6 tons/ha CO₂ (Chavan & Rasal, 2012). Research indicates that mango trees have various carbon stocks, including 1.5 tons/ha CO₂/ha, 80.74 tons CO₂/ha, and 45–85 tons CO₂/ha (Babbar et al., 2021; Ganeshamurthy et al., 2019; Prasanna & Selvaraj, 2016). According to the study done on Jackfruit, it is reported to contain 26.7 tons of CO₂ per hectare (Manilay et al., 2021). In addition, estimates of CO₂ sequestration per tree for guava (0.012 tons CO₂/tree) and mango (0.21 tons CO₂/tree) were reported by the researchers (Kumar & Kunhamu, 2021).

5.1.2. Above and belowground biomass

A study done in Indonesia estimated that the carbon sequestration capacity of fruit tree biomass, with average carbon stock values ranging from 382 Gg to 245,726 Gg (Gunamantha et al., 2021). Accordingly, Ades fruits have a carbon sequestration potential of 951.1356 tons per hectare above ground and 191.5545 tons per hectare below ground, which can help reduce climate change (Shiferaw et al., 2022). High CO₂ exposure is reported to boost photosynthesis in tropical and subtropical fruits, and increase tree biomass, thereby reducing atmospheric carbon dioxide (Pandya et al., 2013). The coffee agroforestry system’s in the above-ground carbon component has a higher carbon store compared to other carbon components (Niguse et al., 2022). Soil organic carbon and below-ground carbon pools are reported as the next largest sources of carbon storage, each with an average capacity of 156.6 tons of carbon per hectare (Ajonina et al., 2014). In general, the coffee agroforestry system is stated to store 30.5 Gg of carbon, with coffee plants specifically contributing 4.4 Gg to the system Table 2.

Table 2. Carbon stock potential of fruit trees in different carbon pools

No.	Carbon pools in the fruit tree ecosystems	Level of carbon stock	Ref.
1	Store carbon	Photosynthesis converts CO2 into glucose and oxygen, while trees store carbon in biomass and soil organic matter. Fruit plants sequester CO2 differently with varying carbon stocks, such as mango and jackfruit.	Manilay et al., (2021)
2	Above & below ground biomass	Indonesian study finds fruit tree biomass has high carbon sequestration capacity, with an average sequestration of 951.1356 tons per hectare and 191.5545 tons per hectare. Coffee plants contribute 4.4 Gg.	Shiferaw et al., (2022)
3	Litter biomass	Litter has low carbon storage capacity and low sequestration potential, but aboveground litter input increases soil organic carbon pools and microbial biomass, benefiting sequestration despite decomposition.	(Bhattacharyya et al., (2022)
4	Soil carbon	Soil is the largest terrestrial carbon sink, storing organic matter. Reducing loss involves minimal disturbance, clay particle management, and organic carbon addition.	(Mayer et al., (2022)

5.1.3. Litter biomass

According to a study done to assess the carbon sequestration potential of Ades fruits and its contribution to climate change mitigation, litter has a poor carbon storage capacity and low sequestration potential, with a mean carbon storage capacity of 2.1 tons C/ha⁻¹ (Kassahun et al., 2015). Additionally, the litter biomass had an average carbon dioxide sequestration potential of 9.44 tons/ha⁻¹. Litter addition is reported to increase soil organic carbon (SOC) pools and microbial biomass, indicating that aboveground litter inputs benefit SOC sequestration despite the accelerated decomposition (Feng et al., 2022). Moreover, rapid and consistent changes in soil C content with altered litter inputs provided important insights into plant residue management to enhance soil C sequestration (Xu et al., 2021). In general, aboveground plant litter inputs are important sources of soil carbon (C) (Table 2).

5.1.4. Soil carbon

Soil is the world’s greatest terrestrial carbon sink, with soil organic matter constituting the majority of the carbon stored there (Berhe et al., 2008). How much carbon is kept in soil organic matter depends on the addition of carbon from decomposing plant residues and carbon loss through respiration, and both natural and human disturbance of the soil (Trumbore, 1997). Thus, by using different agricultural techniques that disturb little soil, farmers may be able to slow down or perhaps stop the loss of carbon from their fields (Reicosky, 2003). There was a substantial correlation between the distribution of individual soil particles and soil organic carbon (Gunamantha et al., 2021). For instance, the association between soil organic carbon and sand and silt particles is reported to be extremely poor and hostile (Dong et al., 2017). Sandy soils are stated to have low organic carbon content, but clay particles have the strongest positive relationship (Eusterhues et al., 2003). Hence, in order to trap more carbon in the soil, soil management and the addition of organic carbon through crop leftovers or manure are more crucial than the texture of the soil (Blanco-Canqui, 2013). Moreover, at a depth of 0–50 cm, 0–75 cm, and 0–25 cm, the largest positive association between clay dispersion and soil organic carbon was reported (Somasundaram et al., 2017).

Both exchangeable potassium and available phosphorus exhibit a stronger negative correlation with soil organic carbon (Jakšić et al., 2021). Soil carbon storage decreases with increased plant nutrients, but their availability is strongly linked to soil organic carbon (Elbasiouny et al., 2022). In addition, total nitrogen and available phosphorus were reported to have positive and negative relationships, with negligible effects at low concentrations. Similarly, soil organic carbon stock at a depth of 60 cm is reported from 73.2 tons C/ha⁻¹ for the Syzygium-shaded coffee stratum to 103.2 ton C/ha⁻¹ for the mixed-tree-shaded coffee stratum (Niguse et al., 2022). Thus, the presence of multiple plant species with varying degrees of decomposition could account for the high soil organic carbon stores in the mixed tree-shaded layer (Chatterjee et al., 2019). Organic matter in the soil distresses its capacity to store carbon to decline with the depth (Torn et al., 1997). While the distribution of individual soil particles did not demonstrate a significant association with soil organic carbon, and the average carbon stock per hectare of soil reported was 440 kg/ha⁻¹ (Mathew et al., 2020).

5.2. Environmental elements affecting fruit carbon stocks

Research done on factors affecting woody carbon stock in Sirso moist evergreen Afromontane forest, southern Ethiopia: implications for climate change mitigation stated that there were differences in the carbon stock of woody species depending on the kind of community, altitude, and slope gradients (Mewded & Lemessa, 2020). Moreover, geographical factors and vegetation mix are vital when selecting trees for climate change mitigation, especially fruit trees (Mewded & Lemessa, 2020). Different altitudinal gradients are stated to have various quantities of above-ground carbons (Eshetu et al., 2020). For instance, in the upper altitude gradient the maximum above-ground carbon concentration was reported to be 187.3 27 tons/ha⁻¹, while in the lower, it is estimated to be 84.7 9.2 tons/ha⁻¹. The highest value of the upper altitude might be due to the topography, where the upper altitude has a nearly sharp slope that has isolated itself from human impact. In general, the results has shown that the altitudinal gradient has a significant effect on the above-ground biomass, and when altitude increases, the above-ground carbon also increases (Fotis et al., 2018).

5.2.1. Disturbance level

In addition to environmental conditions, the amount of carbon storage is influenced by a number of factors. For instance, a significant amount of carbon was reported to be stored in the tree biomass and soil in the citrus-based plantings (Yasin et al., 2021). Citrus trees’ age, growth patterns, and management techniques influence carbon stocks, making them potential climate change sequestered through fruit-based agroforestry systems (Dagar & Yadav, 2017). In every least disturbed area, the above ground biomass and carbon stocks are reported to be varied extensively (Gebeyehu et al., 2019).

6. Fruit tree production and research experiences in Ethiopia

Ethiopia’s agricultural sector has just lately started to produce fruit, and the majority of its native fruits are wild, and there are no adequate improved varieties (Rahiel et al., 2018). Most of the fruits grown in commercial farms and orchards are exotic and were only recently introduced to Ethiopia. Producers, merchants, and users are therefore unfamiliar with their management. Fruit production and consumption have a number of problems that need to be properly identified and addressed (Salgueiro et al., 2010). Ethiopia’s fruit is primarily grown in backyard gardens and small-scale farms, with domestic consumption being the primary market (Gebre Mariam, 2003). The most common fruits grown in Ethiopia are peaches, avocado, mangoes, citrus, Lemons, Mandarins, Papayas, Pineapples, and plums, and the quantity is by no means insufficient (Melke & Fetene, 2014). However, children are only collected and served the native fruits like “Agam,” “Kegaa,” “Shola,” and “Koshim” among others.

On the other hand, Ethiopia, where agriculture is the country’s key sector, is severely affected by the recurrent drought and poverty (Mohamed, 2017). Ethiopia primarily uses fruit trees for income generation (domestic market), and household consumption. However, some other African countries are integrating fruit trees for environmental protection and climate change mitigation.

A review done in Malawi reported that appropriate tree management practices can increase carbon sequestration and socioeconomic benefits (Mng’omba & Beedy, 2013).

According to a study conducted in Kampala, Uganda (Africa) to examine the carbon sequestration of fruit trees under various management regimes in 2022, mango fruits have a great potential to sequester carbon emissions and reducing global warming (Ganeshamurthy et al., 2019).

While in Ethiopia, research done on fruit trees’ role in reducing climate change is very limited, rather than most of the studies are focusing on forest trees and shrubs.

A study conducted to compare the biomass and soil carbon stock potential of various agroforestry practices and home gardens in the South Wollo Zone of Amhara regional state of Ethiopia reported that the total carbon stock in the home garden practices was 100.4 Mg C/ha⁻¹, and the highest soil carbon stock was recorded from home garden agroforestry (94.2 Mg C/ha⁻¹), followed by cultivated land (73 Mg C/ha⁻¹) (Seid, 2022). Hence, the results of this study show that home gardens contribute the highest soil organic carbon and biomass, with a mean total ecosystem carbon of 84.3%.

A study done on a comparative assessment of soil organic carbon stock potential under agroforestry practices and other land uses in the lowlands of Bale, Ethiopia, stated that shade-grown coffee agroforestry in Ethiopia’s Dallo Mena district stores the highest carbon (Mengistu & Asfaw, 2017). Consequently, agroforestry practices offer a dual advantage including income generation, providing ecosystem services, storing and conserving significant amounts of carbon inside the system (Montes-Londoño, 2017). In addition, coffee fruits are the most profitable land-use practices since they provide a variety of benefits like income generation, carbon sequestration, and biodiversity preservation (Niguse et al., 2022). In July 2019, Ethiopia’s government gained international attention when it announced that it had set a record by planting more than 350 million trees in a single day (Fikreyesus et al., 2022). The Green Legacy Initiative programme, which aims to plant 20 billion trees in four years, was launched by the country’s leaders in 2019 (Fikreyesus et al., 2022). However, the government of Ethiopia lacks interest to integrate multipurpose fruits with forest trees. In 2023, Ethiopia’s government and society are prioritizing the promotion and advocacy of versatile fruit trees, which are projected to become the primary focus in the coming years.

7. The role of fruit trees for sustainable environment

Fruit tree planting is important for a healthy and prosperous future because all fruit trees play a crucial role in maintaining the balance of our planet (De Groot et al., 2002). Here are a few of the contributions that fruit plants perform. For example, storm water management in urban areas are reported to require trees including fruit trees for hydration and reducing erosion problems (Zhang et al., 2016). Thus, the inclusion of trees may assist in some of the drainage concerns if the area is extremely wet (Figure 2).The best places to put trees and other vegetation as a mitigation means are around buildings or nearby the pavement in parking lots and on streets (Akbari, 2009). But, the most efficient way to cool a structure is reported to plant deciduous trees or vines to the west, particularly if they shade the building’s windows and a portion of its roof (Maleki, 2011). Moreover, vegetation is described to reduce urban heat by providing shade and evapotranspiration, because tree plants cool the environment (Aboelata & Sodoudi, 2019). For instance, shaded surfaces are stated to be cool between 11–25°C, absorb less heat, and reduce radiation from direct exposed areas (Bayu, 2022). In addition, comparative monoculture integration of fruit trees with other plant species slightly increases crop diversity, which benefits some taxa’s species richness without reducing yields (Jayathilake et al., 2021).

Figure 2. Contributions of fruit trees to the sustainable environment (short summary).

Moreover, integrating native fruit plants in coffee farms for bird conservation is indicated to be crucial (Carlo et al., 2004).

Fruit trees produce oxygen and absorb carbon dioxide, making substantial contributions to the oxygen and carbon dioxide cycle (Olah et al., 2009).

Fruit trees engage in a process known as photosynthesis, which converts water and carbon dioxide gas into oxygen and glucose using sunlight (Mohan et al., 2009). The trees aid in air purification and better air quality during the gas-exchanging process (Bolund & Hunhammar, 1999). Fruit trees are therefore critical to the oxygen and carbon dioxide cycles and to the world ecology (Wittwer, 1995). Foot-tall trees, like apple trees, can sustain four people at once by releasing up to 15 tons of oxygen per acre while absorbing 10–20 tons of carbon dioxide annually (Uning et al., 2020).

Fruit-bearing trees mitigate the negative effects of CO₂ pollution, yet they still require CO₂ for survival (Ramirez & Kallarackal, 2015). The air is cleaned or filtered by trees, which remove carbon dioxide and release new oxygen into the atmosphere (Cooper & Alley, 2010). One acre of mature fruit trees is reported to be able to absorb as much CO₂ as 26,000 miles of driving (Aiyeloja, 2013).

8. Review gaps and future lines of work

In the coming years, fruits carbon sequestration research is poised to revolutionize fruit production and sustainable environment. In Ethiopia, the fruit production segment is hindered by poor growers’ skill and lack of improved varieties. Although there are numerous types of fruits in the country, they are not characterized based on their role of carbon sequestration. Even in agroforestry systems, the idea of carbon sequestration is almost abandoned. Researches conducted on multipurpose and resilient fruits are not adequate. In addition, international cooperation with institutes, companies, and universities are weak pertinent to climate change mitigation. The societal insights about the cultivation of multipurpose fruits are not widely addressed. Therefore, fruits production models should be calibrated and integrated with predictive and systematic agronomic approaches.

9. Conclusion

In conclusion, climate change is a pressing issue in Ethiopia exacerbated by human activities such as fossil fuel consumption and deforestation. Although, 85% of the country’s population depends on weather-dependent agriculture, climate change is posing risks to realizing development and poverty reduction goals in Ethiopia. The country has already experienced high temperatures and diminutive precipitation. In Ethiopia, climate variation is affecting environmental settings and causing soil erosion, drought, desertification, biodiversity loss, flooding, and water pollution, and health threats. On the other side, different countries in the world are using fruits for various purposes such as for food and nutrition security, climate change mitigation, and sustainable development. Because fruit trees are an important carbon pool used to store large quantities of carbon in their biomass. Both above and below ground biomass are used to store different amounts of carbon. Globally, multipurpose fruit trees are widely used or cultivated to sequester carbon from the atmosphere. However, it is not widely practiced in Ethiopia, rather unintended fruit cultivation activities are adept largely in the homestead areas. The type of fruits proposed for cultivation is not considered on the basis of their versatile advantage, rather they are selected based on their economic response alone. Thus, fruit tree cultivation experiences are not assuming climate change mitigation strategies through carbon sequestration in Ethiopia. In general, in addition to forest trees, the cultivation of multipurpose fruits is paramount to protect our environment. Hence, selection of fruits on the basis of their nutrition composition and the role of carbon sequestration are vital for countries such as Ethiopia.

Authors’ contribution

The concept of the study was developed by Yohannes Gelaye while the design, data analysis and synthesis, interpretation and drafting and final write-up of the paper were performed by both Yohannes Gelaye and Sewnet Getahun.

Availability of data and materials

Data sharing is not applicable to this article as no new data were created or analyzed in this study.

Acknowledgments

The authors acknowledge https://hindawi.writefull.ai/software.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/23311932.2023.2294544.

Additional information

Funding

This work was not supported by any funding.

Notes on contributors

Yohannes Gelaye

Yohannes Gelaye is a lecturer and researcher in the Department of Horticulture, College of Agriculture and Natural resources, Debre Markos University, Ethiopia. He did his Master’s degree in Horticulture at Bahir Dar University, Ethiopia. Since December 2014, Yohannes is working at Debre Markos University and teaching courses like Plant biotechnology, Plant propagation, Design and agricultural experimentation, Vegetable and fruit crops production and management, Ornamental horticulture, Plant physiology, Coffee production, processing and quality control, Crop protection, and Nutrition sensitive agriculture. His research interest is Biotechnology, Biochar in agriculture, Adapting to drought stress, Byproduct utilization, Climate change induced disease and pests, Drought induced physio-morphological, molecular and biochemical changes, Agro-nanotechnology, Artificial Intelligence, Crops and soil improvement, Postharvest science and technology, Food safety, and Nutrition, and food security.