Agroforestry systems are believed to provide a number of ecosystem services; however, until recently evidence in the agroforestry literature supporting these perceived benefits has been lacking. This special issue brings together a series of papers from around the globe to address recent findings on the ecosystem services and environmental benefits provided by agroforestry. As prelude to the special issue, this paper examines four major ecosystem services and environmental benefits of agroforestry: (1) carbon sequestration, (2) biodiversity conservation, (3) soil enrichment and (4) air and water quality. Past and present evidence clearly indicates that agroforestry, as part of a multifunctional working landscape, can be a viable land-use option that, in addition to alleviating poverty, offers a number of ecosystem services and environmental benefits. This realization should help promote agroforestry and its role as an integral part of a multifunctional working landscape the world over.
Montado decline has been reported since the end of the nineteenth century in southern Portugal and increased markedly during the 1980s. Consensual reports in the literature suggest that this decline is due to a number of factors, such as environmental constraints, forest diseases, inappropriate management, and socioeconomic issues. An assessment on the pattern of montado distribution was conducted to reveal how the extent of land management, environmental variables, and spatial factors contributed to montado area loss in southern Portugal from 1990 to 2006. A total of 14 independent variables, presumably related to montado loss, were grouped into three sets: environmental variables, land management variables, and spatial variables. From 1990 to 2006, approximately 90,054 ha disappeared in the montado area, with an estimated annual regression rate of 0.14 % year−1. Variation partitioning showed that the land management model accounted for the highest percentage of explained variance (51.8 %), followed by spatial factors (44.6 %) and environmental factors (35.5 %). These results indicate that most variance in the large-scale distribution of recent montado loss is due to land management, either alone or in combination with environmental and spatial factors. The full GAM model showed that different livestock grazing is one of the most important variables affecting montado loss. This suggests that optimum carrying capacity should decrease to 0.18–0.60 LU ha−1 for livestock grazing in montado under current ecological conditions in southern Portugal. This study also showed that land abandonment, wildfire, and agricultural practices (to promote pastures, crops or fallow lands) were three significant variables influencing montado loss.
The many benefits of agroforestry are well-documented, from ecological functions such as biodiversity conservation and water quality improvement, to cultural functions including aesthetic value. In North American agroforestry, however, little emphasis has been placed on production capacity of the woody plants themselves, taking into account their ability to transform portions of the landscape from annual monoculture systems to diversified perennial systems capable of producing fruits, nuts, and timber products. In this paper, we introduce the concept of multifunctional woody polycultures (MWPs) and consider the design of long-term experimental trials for supporting research on agroforestry emphasizing tree crops. Critical aspects of long-term agroforestry experiments are summarized, and two existing well-documented research sites are presented as case studies. A new long-term agroforestry trial at the University of Illinois, “Agroforestry for Food,” is introduced as an experiment designed to test the performance of increasingly complex woody plant combinations in an alley cropping system with productive tree crops. This trial intends to address important themes of food security, climate change, multifunctionality, and applied solutions. The challenges of establishing, maintaining, and funding long-term agroforestry research trials are discussed.
Olive groves are among the most significant agroforestry systems for ecological, social and economic benefits not only in the Mediterranean area but also in China. Over the long course of olive cultivar introduction, the great majority of global olive development has taken place in Mediterranean regions, and later, it spread to the rest of the world, including China. A true picture of the current status of the olive industry in China is still lacking. This unique study aims to gain a better understanding of the opportunities and challenges in the Chinese olive industry. This study involved both a literature review as well as a field investigation to analyze the study questions, and it consisted of the historical perspective, current status, trends, policies, opportunities and challenges. The introduction and domestication of the olive has been performed in China since 1964. The olive is a suitable tree with a high survival rate in many regions in the southern part of the country, but the olive industry was just recently built up in Gansu, Sichuan, Yunnan after 2000 because only a few areas could produce olive fruit-bearing trees. By 2030, the total plantation areas are expected to increase from 66,400 ha (2016) to approximately 193,400 ha. In the past, approximately 165 cultivars were introduced, among which 28 cultivars that exhibited excellent performance were preliminarily selected. Among the dominant areas for these olives, Longnan has been shown to be the best representative region through the rapid development of its olive industry. Olive oil imports exceeded 90% of total consumption in China, and this import volume increased rapidly by 60 to 70%, except in the last 3 years. A lack of research advances still remains a large challenge for the scientific community. Olive is one of the most important fruit trees can grow in agroforestry systems. At present, the Chinese olive industry is at its initial stage of development, it will be a great potential in the next 20 years especially for olive agroforestry in the low olive fruit production areas. Whether developing olive monoculture or agroforestry more practical measures should be made in the future. This study analyzes the Chinese olive industry from an ultramodern global perspective, with the aim of providing effective measures through a multi-analysis of low production. This study may help to enhance the olive industry.
Land use systems that integrate woody vegetation with livestock and/or crops and are recognised for their biodiversity and cultural importance can be termed high nature and cultural value (HNCV) agroforestry. In this review, based on the literature and stakeholder knowledge, we describe the structure, components and management practices of ten contrasting HNCV agroforestry systems distributed across five European bioclimatic regions. We also compile and categorize the ecosystem services provided by these agroforestry systems, following the Common International Classification of Ecosystem Services. HNCV agroforestry in Europe generally enhances biodiversity and regulating ecosystem services relative to conventional agriculture and forestry. These systems can reduce fire risk, compared to conventional forestry, and can increase carbon sequestration, moderate the microclimate, and reduce soil erosion and nutrient leaching compared to conventional agriculture. However, some of the evidence is location specific and a better geographical coverage is needed to generalize patterns at broader scales. Although some traditional practices and products have been abandoned, many of the studied systems continue to provide multiple woody and non-woody plant products and high-quality food from livestock and game. Some of the cultural value of these systems can also be captured through tourism and local events. However there remains a continual challenge for farmers, landowners and society to fully translate the positive social and environmental impacts of HNCV agroforestry into market prices for the products and services.
The importance of agroforestry systems as carbon sinks has recently been recognized due to the need of climate change mitigation. The objective of this study was to compare the carbon content in living biomass, soil (0–10, 10–20, 20–30 cm in depth), dead organic matter between a set of non-agroforestry and agroforestry prototypes in Chiapas, Mexico where the carbon sequestration programme called Scolel’te has been carried out. The prototypes compared were: traditional maize (rotational prototype with pioneer native trees evaluated in the crop period), Taungya (maize with timber trees), improved fallow, traditional fallow (the last three rotational prototypes in the crop-free period), Inga-shade-organic coffee, polyculture-shade organic coffee, polyculture-non-organic coffee, pasture without trees, pasture with live fences, and pasture with scattered trees. Taungya and improved fallow were designed agroforestry prototypes, while the others were reproduced traditional systems. Seventy-nine plots were selected in three agro-climatic zones. Carbon in living biomass, dead biomass, and soil organic matter was measured in each plot. Results showed that carbon in living biomass and dead organic matter were different according to prototype; while soil organic carbon and total carbon were influenced mostly by the agro-climatic zone (P < 0.01). Carbon density in the high tropical agro-climatic zone (1,000 m) was higher compared to the intermediate and low tropical agro-climatic zones (600 and 200 m, respectively, P < 0.01). All the systems contained more carbon than traditional maize and pastures without trees. Silvopastoral systems, improved fallow, Taungya and coffee systems (especially polyculture-shade coffee and organic coffee) have the potential to sequester carbon via growing trees. Agroforestry systems could also contribute to carbon sequestration and reducing emissions when burning is avoided. The potential of organic coffee to maintain carbon in soil and to reduce emissions from deforestation and ecosystem degradation (REDD) is discussed.
Potential benefits and costs of agroforestry practices have been analysed by experts, but few studies have captured farmers’ perspectives on why agroforestry might be adopted on a European scale. This study provides answers to this question, through an analysis of 183 farmer interviews in 14 case study systems in eight European countries. The study systems included high natural and cultural value agroforestry systems, silvoarable systems, high value tree systems, and silvopasture systems, as well as systems where no agroforestry practices were occurring. A mixed method approach combining quantitative and qualitative approaches was taken throughout the interviews. Narrative thematic data analysis was performed. Data collection proceeded until no new themes emerged. Within a given case study, i.e. the different systems in different European regions, this sampling was performed both for farmers who practice agroforestry and farmers who did not. Results point to a great diversity of agroforestry practices, although many of the farmers are not aware of the term or concept of agroforestry, despite implementing the practice in their own farms. While only a few farmers mentioned eligibility for direct payments in the CAP as the main reason to remove trees from their land, to avoid the reduction of the funded area, the tradition in the family or the region, learning from others, and increasing the diversification of products play the most important role in adopting or not agroforestry systems.
Agroforestry systems may play an important role in mitigating climate change, having the ability to sequester atmospheric carbon dioxide (CO2) in plant parts and soil. A meta-analysis was carried out to investigate changes in soil organic carbon (SOC) stocks at 0–15, 0–30, 0–60, 0–100, and 0 ≥ 100 cm, after land conversion to agroforestry. Data was collected from 53 published studies. Results revealed a significant decrease in SOC stocks of 26 and 24% in the land-use change from forest to agroforestry at 0–15 and 0–30 cm respectively. The transition from agriculture to agroforestry significantly increased SOC stock of 26, 40, and 34% at 0–15, 0–30, and 0–100 cm respectively. The conversion from pasture/grassland to agroforestry produced significant SOC stock increases at 0–30 cm (9%) and 0–30 cm (10%). Switching from uncultivated/other land-uses to agroforestry increased SOC by 25% at 0–30 cm, while a decrease was observed at 0–60 cm (23%). Among agroforestry systems, significant SOC stocks increases were reported at various soil horizons and depths in the land-use change from agriculture to agrisilviculture and to silvopasture, pasture/grassland to agrosilvopastoral systems, forest to silvopasture, forest plantation to silvopasture, and uncultivated/other to agrisilviculture. On the other hand, significant decreases were observed in the transition from forest to agrisilviculture, agrosilvopastoral and silvopasture systems, and uncultivated/other to silvopasture. Overall, SOC stocks increased when land-use changed from less complex systems, such as agricultural systems. However, heterogeneity, inconsistencies in study design, lack of standardized sampling procedures, failure to report variance estimators, and lack of important explanatory variables, may have influenced the outcomes.
The Portuguese montado is an agro-silvo pastoral system quite similar to the dehesa in Spain, and covering in Portugal most of the Southern region of the country, Alentejo. The trees in the montado are cork oh holm oak, and the system is mostly acknowledged due to the cork production, but also due to its singular savanna like land cover pattern, its multiple and complementary productions, the support of a diversity of ecosystems services and its biodiversity. The present special issue covers the diversity of components of the montado and of perspectives required to understand and assess the functioning of the system. This Editorial introduces the montado system, describes its extension and similarities to the dehesa in Spain, and addresses the multiple productions and externalities of the montado. It also refers to the several components of the system. It focus on the uniqueness and values of this system, stressing its potential and threats, and the requirements for integrated knowledge production. In the end of the Editorial, each one of the papers that compose the special issue are presented.
Vitellaria paradoxa is one of the most economically important trees in West Africa. Although being a key component of most sub-Sahara agroforestry systems, little information and argument exist regarding its biomass and carbon potential. Here, we developed biomass equations for V. paradoxa tree components in Sudanian savannas. A destructive sampling approach was applied, which was based on measuring stem, branch and foliage biomass of thirty individual trees selected from a wide spectrum of diameter at breast height (dbh) and tree height (h). Basal diameter (d(20)), dbh, h and crown diameter (c(d)) were measured and used as predictors in biomass equations. Carbon content was estimated using the ash method. Variance explained in biomass allometric equations ranged from 81 to 98%, and was lower for foliage than for branch and stem biomass models, suggesting that leaf allometries are less responsive to tree size than branch and stem allometries. Stem biomass was best predicted by d(20), branch biomass by dbh, and leaf biomass by crown diameter. For aboveground biomass, adding height to dbh as compound variable (dbh(2)xh) did not make any significant change, as compared with model based on dbh alone. However, adding crown diameter to dbh and height reduced the error by 15% and improved model fits. Carbon contents in V. paradoxa foliage, branch and stem were 55.29, 55.37 and 55.82%, respectively, and higher than reference value suggested by the IPCC. Established allometric equations can be used to accurately predict aboveground biomass of the species in the Sudanian savannas of West Africa.
Research published in this special issue on cocoa agroforestry illustrates the multifunctional role of shade trees for sustaining cocoa production and improving farmers’ livelihoods, and addresses tradeoffs between higher cocoa yield and the provision of ecosystem services to local households and global society. Indeed, the use of diverse shade in cocoa cultivation is threatened by a new drive towards crop intensification. The removal of shade trees diminishes smallholders’ ability to adapt to global change driven by demographic pressure, food insecurity, cocoa price volatility and climate change. Some forms of crop intensification may reduce ecological resilience of cocoa production systems, making adaptation strategies, combining shade trees with innovative management practices, essential for sustaining cocoa yield. Managing trade-offs between yield and environmental services at the cocoa plot and landscape scales requires a multi-disciplinary approach to identify key management options that goes beyond the artificially polarized debates around intensified versus traditional agroforestry practices, or more generally, land-sparing versus land-sharing strategies. The global challenge facing the cocoa sector today is how to increase cocoa production to meet growing demand, without expanding the area under cocoa. This means finding sustainable ways to maintain cocoa production within today’s producing regions, particularly West Africa, through a series of technical innovations geared towards smallholders. Inappropriate intensification may result in heavy deforestation on new pioneer fronts, such as the Congo basin, and existing cocoa being replaced either by other agricultural commodities, or by less resilient and less environmentally friendly production practices.
Agroforestry systems are known to provide ecosystem services which differ in quantity and quality from conventional agricultural practices and could enhance rural landscapes. In this study we compared ecosystem services provision of agroforestry and non-agroforestry landscapes in case study regions from three European biogeographical regions: Mediterranean (montado and dehesa), Continental (orchards and wooded pasture) and Atlantic agroforestry systems (chestnut soutos and hedgerows systems). Seven ecosystem service indicators (two provisioning and five regulating services) were mapped, modelled and assessed. Clear variations in amount and provision of ecosystem services were found between different types of agroforestry systems. Nonetheless regulating ecosystems services were improved in all agroforestry landscapes, with reduced nitrate losses, higher carbon sequestration, reduced soil losses, higher functional biodiversity focussed on pollination and greater habitat diversity reflected in a high proportion of semi-natural habitats. The results for provisioning services were inconsistent. While the annual biomass yield and the groundwater recharge rate tended to be higher in agricultural landscapes without agroforestry systems, the total biomass stock was reduced. These broad relationships were observed within and across the case study regions regardless of the agroforestry type or biogeographical region. Overall our study underlines the positive influence of agroforestry systems on the supply of regulating services and their role to enhance landscape structure.
In temperate Europe alley cropping systems which integrate strips of short rotation coppices into conventional agricultural fields (ACS) are receiving increasing attention. These systems can be used for crops and woody biomass production at the same time, enabling farmers to diversify the provision of market goods. Adding trees into the agricultural land creates various additional benefits for the farmer and society, also known as ecosystem services. However, tree-crop interactions in the temperate region have not been adequately substantiated which is identified as a drawback to the practical implementation of such systems. In order to bridge this gap, the current paper aims to present a comprehensive overview of selected ecosystem services provided by agroforestry with focus on ACS in the temperate region. The literature indicates that compared with conventional agriculture ACS have the potential to increase carbon sequestration, improve soil fertility and generally optimize the utilization of resources. Furthermore, due to their structural flexibility, ACS may help to regulate water quality, enhance biodiversity, and increase the overall productivity. ACS are shown as suitable land use systems especially for marginal sites. Based on the available data collected, we conclude that ACS are advantageous compared to conventional agriculture in many aspects, and therefore suggest that they should be implemented at a larger scale in temperate regions.
In extensive low input farming and in agroforestry systems, the importance for biodiversity of managed productive fields with respect to unmanaged marginal habitats that occupy a low proportion of farm surface, is still poorly understood, contrasting with the well-known key importance of marginal habitats in intensive systems. We analyzed the importance of open and wood pastures and marginal habitats for species richness of Iberian dehesas in Central-Western Spain. We sampled 155 plots classified into 9 general habitat categories: wood pastures (n = 41 plots); open pastures dominated by annual plants (n = 11), by perennial plants (n = 15) and co-dominated by annuals and perennial plants (n = 16); shrublands (n = 19); agricultural crops (n = 12); herbaceous strips (n = 10); woody strips (n = 11); and water bodies (n = 10). In each plot we measured the abundance and species richness of four taxonomic groups: vascular plants, bees, spiders, and earthworms. We detected 431 plant species (37 ± 2.5 CI95 in 100 m2 on average), 60 bee species (3.1 ± 1.1 in 600 m2), 128 spider species (7.4 ± 1.2 in 1.5 m2) and 18 earthworm species (2.5 ± 1.0 in 0.27 m2) in 145 sampling plots. Wood pastures supported fewer species of spiders and earthworms at the plot level, but more plants and earthworm species at the landscape level than open pastures. The low proportion of shared species among habitats and among plots within each habitat type, and the high proportion of species found in unique plots or habitats indicated that every habitat contributes to farm biodiversity. Overall, our extensive survey confirms the hypothesis that the high diversity of dehesas depends on the coexistence within farms of a wide mosaic of habitats, including marginal habitats, which seemed to harbor a disproportionately high number of species as compared to their small extent. Results support policy measures for the maintenance of farm keystone structures such as linear features, small wood/shrub patches and ponds, and reveal that these measures should not be exclusively applied to more intensive farming systems.
Silvopastoral systems are sustainable production systems characterized by greater biodiversity and multifunctionality, compared with other livestock production methods. The complex functional dynamics, however, make silvopastoralism a difficult construct to design and study. The key design criterion for these complex land use practices is to optimize the use of spatial, temporal, and physical resources, by maximizing positive interactions (facilitation) and minimizing negative ones (competition) among the components, for which the principles of sustainable land use systems are relevant. In this paper we address the cardinal questions, how the general ecological principles common to complex natural systems apply to the design and management of silvopastoral systems and how sound management might be identified with the notion of sustained maximum yield. In particular, we explore (1) spatial and temporal heterogeneity for maximizing resource use efficiency, (2) competitive interactions in perennial systems, (3) structural and functional diversity for resource conservation, and (4) integration of the principles of disturbance ecology in silvopastoral system design.
Whilst the benefits of agroforestry are widely recognised in tropical latitudes few studies have assessed how agroforestry is perceived in temperate latitudes. This study evaluates how stakeholders and key actors including farmers, landowners, agricultural advisors, researchers and environmentalists perceive the implementation and expansion of agroforestry in Europe. Meetings were held with 30 stakeholder groups covering different agroforestry systems in 2014 in eleven EU countries (Denmark, France, Germany, Greece, Hungary, Italy, Netherlands, Portugal, Spain, Sweden and the United Kingdom). In total 344 valid responses were received to a questionnaire where stakeholders were asked to rank the positive and negative aspects of implementing agroforestry in their region. Improved biodiversity and wildlife habitats, animal health and welfare, and landscape aesthetics were seen as the main positive aspects of agroforestry. By contrast, increased labour, complexity of work, management costs and administrative burden were seen as the most important negative aspects. Overall, improving the environmental value of agriculture was seen as the main benefit of agroforestry, whilst management and socio-economic issues were seen as the greatest barriers. The great variability in the opportunities and barriers of the systems suggests enhanced adoption of agroforestry across Europe will be most likely to occur with specific initiatives for each type of system.
Agroforestry has importance as a carbon sequestration strategy because of carbon storage potential in its multiple plant species and soil as well as its applicability in agricultural lands and in reforestation. The potential seems to be substantial; but it has not been even adequately recognized, let alone exploited. Proper design and management of agroforestry practices can make them effective carbon sinks. As in other land-use systems, the extent of C sequestered will depend on the amounts of C in standing biomass, recalcitrant C remaining in the soil, and C sequestered in wood products. Average carbon storage by agroforestry practices has been estimated as 9, 21, 50, and 63 Mg C ha−1 in semiarid, subhumid, humid, and temperate regions. For smallholder agroforestry systems in the tropics, potential C sequestration rates range from 1.5 to 3.5 Mg C ha−1 yr−1. Agroforestry can also have an indirect effect on C sequestration when it helps decrease pressure on natural forests, which are the largest sink of terrestrial C. Another indirect avenue of C sequestration is through the use of agroforestry technologies for soil conservation, which could enhance C storage in trees and soils. Agroforestry systems with perennial crops may be important carbon sinks, while intensively managed agroforestry systems with annual crops are more similar to conventional agriculture. In order to exploit this vastly unrealized potential of C sequestration through agroforestry in both subsistence and commercial enterprises in the tropics and the temperate region, innovative policies, based on rigorous research results, have to be put in place.
To meet the environmental challenges that are presently confronting society, the narrow focus on agricultural production needs to be altered to one that places equal value on the generation of crucial ecosystem services. Current research shows that perennial intercropping systems such as agroforestry may be a feasible alternative. Based on studies during the establishment of edible forest gardens in 12 participating farms in Sweden, this paper explores the potential of utilizing multi-strata designs for food production in temperate, high-income countries. Design and species composition of such gardens, types of food they provide, and how they would best fit into the present landscape are discussed. Factors for success and major problems related to the establishment are shared. Potential benefits were found to be closely related to a thorough analysis of the social and ecological contexts before establishment. Characteristics of the site and goals of the garden need to guide species and design choices. If forest garden approaches to food production should contribute to more than local self-sufficiency, the gardens need to increase in scale. Marginal lands and transitions areas between different land uses may be appropriate. Large knowledge gaps concerning potential production, social and economic benefits, and agronomic issues were identified.
Rotational woodlots with N-2-fixing trees may be efficient agroforestry systems, allowing farmers to alternate agricultural and wood-energy production on the same area. However, their long-term effect on soil fertility is poorly understood. The aim of this study was to investigate the influence of successive phases of Acacia auriculiformis stands growing in rotation with crops on the chemical properties of sandy and very poor tropical soils. The study was conducted 22years after the afforestation of humid herbaceous savannah in Mampu, Democratic Republic of Congo. The chemical properties of top soil (0-20cm) from control savannah plots were compared with those from acacia plots that had undergone one, two or three rotations of acacia during the 22year period. We found that the soil properties under non-harvested acacia stands in a 1st rotation and under acacia stands in a 2nd or 3rd rotation following charcoal production and maize and cassava cultivation were similar. Soils under all acacia stands had higher C, N and NO3N contents, but were more acidic, and had lower contents of exchangeable Ca, Mg, K and Na than the control savannah soils. Despite the increase in soil C and N, the sustainability of the acacia rotational agroforestry system after 22years of practice is in question due to the steady decrease of soil cations, soil acidification and the risk of a decline in tree and crop productivity. To improve the nutrient balance and the sustainability of this system, different practices are recommended such as the debarking of tree stems before carbonization, the restitution of small branches and charcoal residues to the soil, and the supply of natural rock phosphate.
Agroforestry system has the enormous capacity to achieve social, economic, and environmental goals by optimizing land productivity. The aim of the present study was to evaluate the land potentiality in India for agroforestry based on FAO land suitability criteria utilizing various land, soil, climate, and topographic themes. This was achieved in GIS Domain by integrating various thematic layers scientifically. The analysis of land potentiality in India for agroforestry suitability reveals 32.8% as highly suitable (S1), 40.4% moderately suitable (S2), 11.7% marginally suitable (S3), and 9.1% not suitable (NS). About 52% of land of India is under the cropland category. In addition, it revealed that the 46% of these cropland areas fall into high agroforestry suitable category S1, and provide huge opportunity for harnessing agroforestry practices. Furthermore, agroforestry suitability mapping in broad ecosystem and in different agroecological regions will assist various projects in India at the regional level. Such results will also boost the various objectives of the National Agroforestry Policy (2014, http://www.cafri.res.in/NAF_Policy.pdf) and policymakers of India where they need to extend it. The potential of geospatial technology can be exploited in the field of agroforestry for the benefit of rural poor people/farmers by ensuring food and ecological security, resilience in livelihoods, and can sustain extreme weather events such as droughts and climate change impact. Such type of research can be replicated in India at village level (local level) to state level (regional level) utilizing the significant themes which affect the agroforestry suitability. This will certainly fetch better results on ground and will significantly assist the management programs.