Silvopastoral system

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The Silvopastorale system ( Latin silva , forest , pascere to feed) is the most widespread form of agro- forestry worldwide . It combines animal husbandry with the cultivation of existing or planted trees or lignified perennial plants . This creates system-related advantages for plants and animals.

history

Agroforestry systems and the underlying Silvopastoralen and Silvoarablen systems have been around for much longer than the term and the corresponding definition .

Some forms of the Silvopastoral systems are already known from the Neolithic Age , the most common representatives are forest pastures or hat forests . The dehesas in Spain and Montado in Portugal have also been around for around 4500 years. Also known since the Neolithic are the semi-open pastures, the purpose of which is to prevent encroachment and to preserve pastureland .

Orchard cultivation as a further form goes back to the Roman Empire and, after a drastic decline, is now more in focus again.

In Central Europe in particular , hedges and windbreaks are known as traditional systems.

Example of a Silvopastoral system in which trees are used as wind protection for the cattle in the pasture. To do this, they were planted in a north-south direction.

Management

Silvopastoral systems occur worldwide in an area from northern coniferous forests to southern tropical savannas . Globally, Silvopastoral systems include trees scattered on pastureland, controlled plant succession , living fences, windbreaks , fodder tree banks , tree plantations with cattle pastures , pastures between tree avenues and other types of intensive management practices.

The aim of this form of agroforestry is to achieve both economic benefits and environmental benefits such as B. Efficient nutrient cycles, carbon storage and the provision of shelter, shade and forage for livestock , in an integrated way. The management can take many forms. It depends on the individual landowners, the climate , the culture and other factors. The basic concept of Silvopastoral systems is the combination of trees, useful plants and cattle. The composition is intentionally designed so that multiple products and benefits can be achieved through the interaction. Silvopastoral systems are in most cases intensively managed in order to maintain their productive and protective functions and interactions and often include cultural measures such as cultivation , fertilization , irrigation , pruning and thinning . The biophysical interactions between the individual species are actively used in order to achieve the optimal yield of various products, including ecosystem services.

Animals in Silvopastoral Systems

The synergy between flora and fauna is the decisive advantage of Silvopastoral systems over other agricultural systems.

Example of a Silvopastoral system with single trees that provide shelter for grazing animals in Colombia.

By grazing young shoots and weeds by livestock, the competition between trees for water and nutrients is minimized. Also scrub or tall grass, which serves as protection for tree-damaging rodents, is eaten or trampled. In addition, the roaming of the animals prevents the area from being converted into forest areas . In addition, water and nutrients get back into the soil through excretions from the animals . Conversely silvopastoral systems allow the animals shelter and in this way protection from the weather. This has been shown to reduce the stress level of the cattle and maintain their eating activity. In addition, the animals can feed on fattening depending on the tree species , e.g. B. acorns or mulberries . There is also the possibility of pruning the trees in order to feed branches and leaves when there is less food in the pastures. Within Silvopastoraler systems, depending on the decisive factors such as the tree species composition and the climatic conditions, the growing season of cattle pastures can be extended.

Ecological aspects

Silvopastoral systems provide important ecosystem services and goods, such as the maintenance of carbon sequestration, soil fertility and soil health, increasing the local water balance , nitrogen fixation and biodiversity .

Carbon bond

The trees enable the aboveground storage of larger amounts of carbon than in a comparable, purely agricultural system. The lower susceptibility of pastures to fires in a seasonally dry climate (compared to forests and bushland) also ensures lower carbon release, since the carbon stored in the grassland can be retained for longer.

Soil fertility, increase in the local water balance and nitrogen fixation

Deep-rooted trees can trap nutrients from deep layers of the soil and reduce leaching, especially nitrogen . Even with droughts different types of wood can deep in the soil profile in water access. Thanks to their enzymatic activity, they also ensure that there is less leaching of veterinary antibiotics. The complementary use of soil resources by plant species that use the top soil layer and trees that use deeper soil layers promote a higher use of nutrients in the entire soil profile. Another positive factor is the influence of deciduous trees. In autumn, the leaves return nutrients to the soil. This can have a positive effect on the growth and supply of the forage plants.

biodiversity

The heterogeneity of space and time in Silvopastoral systems ensures different increases in resources . In this way, high diversity values ​​are maintained at all trophic levels. Trees change the availability of resources (e.g. nutrients , water and light ) and provide an essential source of food and refuge for many species.

Energetic use

Wood for energy recovery is obtained in different ways in Silvopastoral systems. In Asia , Africa and South America in particular , it makes a decisive contribution to the generation of energy in the form of firewood. In the industrialized countries of the northern hemisphere , this use has been largely replaced by the use of liquid fuels . Nonetheless, energy wood production in Silvopastoral systems continues to take place here, for example an overview for Germany can be found on the website of the German Association for Agroforestry . In connection with the goal of providing CO 2 -neutral heat, Silvopastoral systems are also coming back into focus as biomass suppliers. In Germany, more precisely in the southern Black Forest , as part of a potential analysis of the LEADER project, a concept was drawn up by several municipalities and companies to efficiently use woody biomass from Silvopastoral systems for local heating supply . In total, 50% of the participants' annual biomass requirements could be covered. In the following, different types of energy wood production in Silvopastoral systems are presented.

  • Coppice forests are regularly thinned in order to maximize the incidence of light and the production of fruit, and the wood obtained is used for energy. This practice is now represented in Patagonia , Spain and Portugal (Pyrenean oak forests, also known as dehesas ).
  • Pastures are surrounded by "living fences" by trees that are decapitated for firewood production and regularly cut back.
  • In the Mediterranean area , olive groves are used as a Silvopastoral system, where the wood from old and unproductive trees is used as firewood.
  • In Argentina , pines , poplars and willows are cultivated as sawwood and energy wood in combination with C 4 plants and cattle breeding.
  • "Roller chopping" is used in South America in Silvopastoral systems with a rotating, blade-fitted metal roller to roll over bushes and young trees and then use them as energy wood.
  • In the northeastern regions of the United States , among others, are Weymouth pine , hemlock and locust trees used for firewood production in Silvopastoralen systems.

The number of trees within a Silvopastoral system varies depending on the location and type of management. In the dehesas that are widespread in Western Europe , for example, there are typically 30 to 50 oaks per hectare . However, significantly more trees per hectare can also be found in Silvopastoral systems, which are managed with a strong focus on biomass production. In trials in southern Brazil , for example, a number of 1,111 trees per hectare in Silvopastoral systems was found to be optimal for maximizing biomass production.

Future developments and potential

The agroforestry practice in the form of Silvopastoral systems has recently been gaining in importance as a sustainable and climate-resistant livestock system. A major challenge that Silvopastoral systems will face in the coming decades is the need to generate sustainable yields while maintaining ecosystem services. In order to achieve these goals, innovative practices are required that guarantee the ecological survival of Silvopastoral systems, improved competitiveness and social and ecological improvements. This includes the determination of the optimal tree species and density under different uses and ecological constraints. Further potentials in the development of Silvopastoral systems are the identification, selection and introduction of tree, shrub and annual willow plants of species that are suitable for different climatic conditions and grazing characteristics. Silvopastoral systems can reduce soil erosion caused by wind and water, and soil fertility can be increased through closed nutrient cycles and humus enrichment. A sustainable supply of wood-like energy raw materials, better seasonal distribution of work peaks and the reduction of the area-related use of fertilizers and pesticides can also be guaranteed. The latter results in increased biodiversity as well as improved groundwater quality and has positive effects on yields as well as higher yield stability in annual crops due to an improved microclimate. Silvopastoral systems can make a farm more economically resilient. Due to the diversification and expansion of the range of feed and other marketable products, such as firewood , sticks , wood for carving tools and the production of furniture , bark , bast fibers for textiles and ropes, cork , diatomite , fruits , mushrooms and honey , seasonal shortages can arise be mitigated by climate or market factors.

Criticism of Silvopastoral Systems

Compared to a one-sided use of an area as pasture or for the cultivation of woody biomass, Silvopastoral systems are more complex to manage. This also means that management is more expensive and time-consuming. In addition, higher establishment costs may arise, for example due to the impossibility of using an area during the conversion to a Silvopastoral system.

The management of Silvopastoral systems requires specialist knowledge and experience with this practice is often not available; thus the risk of degradation of the system through incorrect use increases (for example through excessive grazing or browsing by natural regeneration by goats ). Not only farm animals , but also wild animals such as deer or elk can damage trees in Silvopastoral systems by grazing or rubbing against trunks.

The impossibility of accurately predicting the effects of the interaction of natural and planned events ( flooding , fire, drought , timber harvest ) and the feed intake of large grazing animals also represents a challenge in connection with the operation of Silvopastoral systems.

The combination of trees and forage plants creates competition for light, water and nutrients between these system components . This results in a lower yield of the individual products compared to monoculture use . Since the legal framework is often designed in favor of monocultures and Silvopastoral systems are often excluded from state subsidies , the earnings situation is correspondingly difficult.

Individual evidence

  1. ↑ a b c d e f g h i j k l m n o Moreno, Gerardo and Rolo, Victor: "Agroforestry practices: silvopastoralism". Burleigh Dodds Science Publishing Limited, 2019, accessed June 10, 2020 .
  2. ↑ a b c d e Nerlich, Graff-Hönninger and Claupein (2012): "Agroforestry in Europe: a review of the disappearance of traditional systems and development of modern agroforestry practices, with emphasis on experiences in Germany" . Ed .: Springer Science + Business Media BV 2012.
  3. ↑ trees and willow (silvopastoral systems). Retrieved April 20, 2020 .
  4. ^ A b c Tobias Plieninger and Lynn Huntsinger: "Rangeland Ecology & Management". Retrieved May 20, 2020 .
  5. ↑ a b Shibu Jose, WD Walter and B. Mohan Kumar: "Ecological considerations in sustainable silvopasture design and management" . 2019.
  6. ^ Garrett, H., W. Rietveld, R. Fisher: "North American Agroforestry: An Integrated Science and Practice" . Ed .: American Society of Agronomy. 2000.
  7. ↑ Nerlich, Graff-Hönninger and Claupein: "Agroforestry in Europe: a review of the disappearance of traditional systems and development of modern agroforestry practices, with emphasis on experiences in Germany" . Ed .: Springer Science + Business Media BV 2012.
  8. ^ Website of the German Association for Agroforestry. Retrieved June 18, 2020 .
  9. ^ Agroforestry map - agroforestry
  10. ↑ https://www.leader-suedschwarzwald.de/
  11. ↑ a b c d e Tibor Hartel and Tobias Plieninger: European Wood-pastures in Transition . 2014.
  12. ^ A b Pablo Luis Peri, Francis Dube and Alexandra Varella: "Silvopastoral Systems in Southern South America" . Springer International Publishing Switzerland, 2016, ISBN 978-3-319-24107-4 .
  13. ^ M. Castro: "Agroforestry in Europe: Current Status and Future Prospects" . Springer Science + Business Media BV, 2009, ISBN 978-1-4020-8271-9 .
  14. ^ PL Peri et al: “Carbon Sequestration in Temperate Silvopastoral Systems, Argentina” . Springer International Publishing AG, 2017, ISBN 978-3-319-69370-5 .
  15. ↑ Joseph Orefice, John Carroll, Drew Conroy and Leanne Ketner: "Agroforestry Systems". Springer Verlag, 2017, accessed on May 12, 2020 (English).
  16. ↑ Plieninger, Tobias and Huntsinger, Lynn: Complex Rangeland Systems: Integrated Social-Ecological Approaches to Silvopastoralism . Ed .: Rangeland Ecology & Management. tape 71 , 2018.