Bio-economic process-based modelling methodology for measuring and evaluating the ecosystem services provided by agroforestry systems

Doutoramento em Engenharia Florestal e dos Recursos Naturais / Instituto Superior de Agronomia. Universidade de LisboaAgroforestry integrates woody vegetation with crop and/or animal production. This combination can benefit from ecological and economic interactions that allow better use of natural resources and improved economic performance. But despite financial support offered through policy, the implementation of new agroforestry systems has not been widespread in the European Union. This thesis aimed to develop additional scientific knowledge on the potential of agroforestry systems in terms of productivity and environmental benefits. The method consisted in improving a bio-physical process-based model (Yield-SAFE) and an integrated bio-economic model (Farm-SAFE) and using both to model four different agroforestry systems in different edaphoclimatic conditions in Europe. Four different agroforestry tree-densities were compared to no-tree and tree-only monoculture alternatives. The results showed that: 1) in terms of productivity, the inclusion of trees in agricultural land increases the overall accumulated energy but the accumulated energy per tree decreases as the tree density of trees increases; 2) agroforestry options present a greater capacity of reducing soil erosion, nitrate leaching and increases the carbon sequestration; 3) agroforestry systems can act as more sustainable methods of food production and 4) options without trees are more interesting financially but these option are also the most polluting. And even though the consideration of a monetary valuation of the environmental services offered, agroforestry options would just become more interesting if there is a change on how public financial help is allocated to the sector. The findings of this work reflect what has been previously seen in scientific literature, particularly in terms of the capacity of agroforestry systems to be more productive than monoculture systems, whilst at the same time providing environmental benefits. However, relatively low profitability means that they still fail to attract farmers, the main agents of agroforestry uptake and currently, arable and forestry tend to receive higher subsidies making these land uses more attractive to farmers but considering environmental benefits would make agroforestry a more interesting optionN/

Investigação e transferência de conhecimento para a promoção de modelos de gestão agroflorestais sustentáveis

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Financial and economic benefits of integrated crop-livestock-tree systems in Europe

•Agricultural monocultures have societal costs •Role for agroforestry •Introducing AGFORWARD •Two case studies on the financial and economic benefits of agroforestry in EuropeEuropean Union’s Seventh Framework Program for research, technological development and demonstration under grant agreement no 61352

Assessing food sustainable intensification potential of agroforestry using a carbon balance method

Food security, climate change mitigation, and land use challenges are interlinked and need to be considered simultaneously. One possible solution is sustainable intensification, which is the practice of increasing food production per area of land whilst also reducing the environmental impacts associated with this. Agroforestry has been stated to be a practice that meets this definition. In this study, a new methodology is presented to assess the potential of different management options as sustainable intensification practices. The methodology is based on comparing the carbon emissions associated with the production of food and the carbon sequestered for that same activity for a particular quantity of food produced over a specific area and over a specific time. The resulting indicator, the “carbon balance” is the difference between the greenhouse gasses emitted (considered as negative values) and carbon sequestered (positive values) estimated in Mg CO2eq per Mg of food produced on one hectare of land for one year. The carbon balance quantifies the global warming potential associated with sustainable intensification by integrating a process-based model with life cycle analysis and is able to estimate above- and below-ground biomass and soil carbon content. This methodology is tested in Portugal for wheat production under crop monoculture and agroforestry systems. The results show agroforestry to be a suitable practice for sustainable intensification compared to a crop monoculture as it just slightly decreased wheat yields whilst providing a positive carbon balance from year 50 onwards of approximately 1 Mg of CO2eq sequestered per Mg of wheat produced

Modelling tree density effects on provisioning ecosystem services in Europe

Agroforestry systems, in which trees are integrated in arable or pasture land, can be used to enable sustainable food, material, and energy production (i.e. provide provisioning ecosystem services) whilst reducing the negative environmental impacts associated with farming. However, one constraint on the uptake of agroforestry in Europe is a lack of knowledge on how specific agroforestry designs affect productivity. A process-based biophysical model, called Yield-SAFE, was used: (1) to quantify the food, material and biomass energy production of four contrasting case study systems in Europe in a common energy unit (MJ ha−1), and (2) to quantify how tree density determined the supply of provisioning ecosystem services. The Yield-SAFE model was calibrated so that simulated tree and crop growth fitted observed growth data for reference monoculture forestry, pasture, and arable systems. The modelled results showed that including trees in pasture or arable systems increased the overall accumulated energy of the system in comparison with monoculture forestry, pasture, and arable systems, but that the accumulated energy per tree was reduced as tree density increased. The greatest accumulated energy occurred in the highest tree density agroforestry system at all the case study sites. This suggests that the capture of environmental resources, such as light and water, for obtaining provisioning services is most effective in high density agroforestry systems. Further modelling should include tree canopy effects on micro-climatic and the impact this has on pasture, crop, and livestock yields, as well as the impact of tree density on the economic value and management of the different systems

Identification of agroforestry systems and practices to model

This report is an output from work-package 6 which contributes to the third objective. Work-package 6 focuses on the field- and farm-scale evaluation of innovation research that have arisen from about 40 agroforestry stakeholder groups created across Europe. Some research, for example tree protection options, are best determined by technical evaluations in the field. However some research questions require a modelling approach to predict, for example, the financial and economic impact of a new practice over a number of years. This report seeks to identify those agroforestry systems and practices which could be usefully assessed using biophysical agroforestry models such as Yield-SAFE (van der Werf et al., 2007) and Hi-sAFe (Talbot, 2011), or bio-economic models such as Farm-SAFE (Graves et al., 2011)

Quantifying regulating ecosystem services with increased tree densities on European farmland

Agroforestry systems have been compared to agricultural and forestry alternatives, providing a land-use solution for additional environmental benefits while maintaining similar levels of productivity. However, there is scarce research assessing such patterns across a pan-European scale using a common methodology. This study aims to improve our understanding of the role of trees in three different regulating ecosystem services—(1) soil erosion, (2) nitrate leaching and (3) carbon sequestration—in traditional and innovative agroforestry systems in Europe through a consistent modeling approach. The systems’ assessment spans environmentally from the Mediterranean environmental region in Portugal to the Continental environmental region in Switzerland and Germany to the Atlantic environmental region in the United Kingdom. Modeled tree densities were compared in the different land-use alternatives, ranging from zero (agriculture with only crops or pasture) to forestry (only trees). The methodology included the use of a biophysical model (Yield-SAFE) where the quantification of the environmental benefits was integrated. Results show a consistent improvement of regulating ecosystem services can be expected when introducing trees in the farming landscapes in different environmental regions in Europe. For all the systems, the forestry alternatives presented the best results in terms of a decrease in soil erosion of 51% (±29), a decrease of nearly all the nitrate leaching (98% ± 1) and an increase in the carbon sequestration of up to 238 Mg C ha−1 (±140). However, these alternatives are limited in the variety of food, energy and/or materials provided. On the other hand, from an arable or pure-pasture alternative starting point, an increase in agroforestry tree density could also be associated with a decrease in soil erosion of up to 25% (±17), a decrease in nitrates leached of up to 52% (±34) and an increase in the carbon sequestered of 163 Mg C ha−1 (±128) while at the same time ensuring the same levels of biomass growth and an increase in product diversificatio

Dry deposition of air pollutants on trees at regional scale: a case study in the Basque Country

There is increased interest in the role of trees to reduce air pollution and thereby improve human health and well-being. This study determined the removal of air pollutants by dry deposition of trees across the Basque Country and estimated its annual economic value. A model that calculates the hourly dry deposition of NO2, O3, SO2, CO and PM10 on trees at a 1 km x 1 km resolution at a regional scale was developed. The calculated mean annual rates of removal of air pollution across various land uses were 12.9 kg O3 ha−1, 12.7 kg PM10 ha−1, 3.0 kg NO2 ha−1, 0.8 kg SO2 ha−1 and 0.2 kg CO ha−1. The results were then categorised according to land use in order to determine how much each land use category contributed to reducing air pollution and to determine to what extent trees provided pollution reduction benefits to society. Despite not being located in the areas of highest pollutions, coniferous forests, which cover 25% of the land, were calculated to absorb 21% of the air pollution. Compared to other land uses, coniferous forests were particularly effective in removing air pollution because of their high tree cover density and the duration of leaf life-span. The total economic value provided by the trees in reducing these pollutants in terms of health benefits was estimated to be €60 million yr−1 which represented around 0.09% of the Gross Domestic Product of the Basque Country in 2016. Whilst most health impacts from air pollution are in urban areas the results indicate that most air pollution is removed in rural areas

Whole system valuation of arable, agroforestry and tree-only systems at three case study sites in Europe

There is an increasing demand to study the long-term effects of land use from both local farm and wider societal and environmental perspectives. This study applied an approach to evaluate both the financial profitability of arable, agroforestry, and tree-only systems and the wider societal benefits over a period of 30-60 years. The biophysical inputs and yields from the three systems were modelled for three case study sites in the United Kingdom, Spain, and Switzerland, using a tree and crop simulation model called Yield-SAFE. A bio-economic model called Farm-SAFE was then used to compare the financial (EAVF) and economic (or societal) equivalent annual values (EAVE) by including monetary values for five environmental externalities: carbon dioxide emissions, carbon sequestration, soil erosion by water, and nitrogen and phosphorus balances. Across the three case studies, arable farming generated higher farm incomes than the agroforestry or tree-only systems, but the arable systems also created the greatest environmental costs. By comparison the agroforestry and tree-only systems generated lower CO2 emissions and sequestered more carbon. Applying monetary values to the environmental externalities meant that the EAVE of the agroforestry and tree-only systems were greater or similar to that for the arable system in the UK case study. In Spain, the slow predicted growth of the trees meant that, even after including the environmental externalities, the arable system created greater societal benefit than the agroforestry and tree-only systems. In Switzerland, including the environmental externalities increased the attraction of the tree-only system, but the high subsidies for arable and agroforestry systems meant that the EAVE for the agroforestry and arable systems were the most attractive from a farmer’s perspective. A breakeven analysis was used to determine the environmental externality values at which the agroforestry and tree-only systems produced the same societal return as the arable system in each case study. In the UK, a carbon price of ₠16 (t CO2)-1 allowed the EAVE of the agroforestry system to attain parity with the arable EAVE. In both the UK and Spain, an environmental nitrogen cost of ₠3-6 (kg N)-1 was sufficient for the EAVE of the agroforestry and tree-only systems to match those of arable farming. Because trees on farms provide ‘‘economies of multifunction’’ for environmental benefits, the breakeven values will be less if environmental benefits are considered together as packages. The described approach provides a method for governments and others to examine the cost effectiveness of new agri-environment measure