Today I'm speaking about my favorite subject which is agroforestry and we're going to talk first, the first part is an introduction to agroforestry. We're going to give you the general concepts, strategies, and then functions in sustainable food production, conservation, restoration. We'll go in several different parts. For motivation for you, we have several different agroforestry systems in the screen from a coffee with native tree species in Costa Rica, alley cropping with maize, and nitrogen-fixing tree, some silvopastoral system where you can see the cattle there with living fences and with other systems and successional agroforestry system, and then multistrata agroforestry system in Ecuador. What is agroforestry? There are so many definitions of agroforestry. Almost everyone has their own definition of agroforestry. You can say in general terms, agroforestry systems integrate woody species into agricultural systems to increase sustainability by tightening the nutrient cycles, favoring soil conservation and biodiversity, improving site conditions and site productivity without the use of a high cost inputs. Agroforestry systems can diversify outputs, decrease risk for the farmer. They can supplement income because they have a variety of outputs and they can provide a number of social and environmental, and economic services as well. Agroforestry is in reality a collective name given to all types of land use systems and technologies [where you are], including woody perennials. Woody perennials can include trees, shrubs, bamboo, sometimes palms, in a deliberate manner. They are deliberately used on the same land management unit, meaning the farm or largening the landscape, combined with agricultural crops or animals in some form of special arrangement or temporal sequence as well. There are two main characteristics that are always present in any agroforestry system. One of them would be the deliberate growing of woody perennials on the same unit of land as agricultural crops or animals, either in some forms of spatial mixture or in a sequence. We say deliberate growing because sometimes you see something that's kind of like a leftover in the landscape. Some cattle may be grazing under some force, but nobody put the cattle there. They just walked out there. So that's not the silvopastoral system, for example, it's not an agroforestry system. There has to be some thinking, some management, some design about the agroforestry system. There must be significant ecological and/or economic interactions between the woody components and the non-woody components of the systems. We're stressing this too because sometimes you see systems that the components don't make too much sense together. If you see, for example, orange trees in combination with pine trees in Misiones in Argentina. They have those systems and you'd say, "Why would you put orange trees under pine trees?" Well, but the reason is an economic one. They're just growing some little pine trees. And in the meantime, they have those orange trees. And they're harvesting oranges in the meantime. So that's an agroforestry system because there is some intention on it and interaction there is an economic one. The definition that we have for agroforestry system in place, that agroforestry always involves two or more species of plants and/or animals, and at least one plant is a woody perennial. If you see a mixed cropping system of corn and beans, that's not an agroforestry systems. You have to have the woody perennial there. The cycle of an agroforestry system is at least one year. You cannot have anything less than one year, especially if you have the perennial species like the trees and/or the shrubs. Even the most simple agroforestry system is more complex than a monocropping system. You can see these systems in the landscape near Nairobi in Kenya. You see the complexity of the landscape and some agroforestry systems are here. These are not agroforestry system. These are simple monocropping systems and there is some forest in the background over here. Agroforestry systems are based on agroecological principles and strategies and those are used in designing and managing agroforestry. The first and most important one is the use of several layers of vegetation where you have herbs, shrubs, trees, and palms. That way you maximize the transformation of solar energy into biomass. There is reduced dependency on agrochemicals inputs and energy. That's because you are depending more on the interactions and synergisms that you have among the biological components of the system. That way you're enhancing nutrient recycling for soil conservation and biological pest control , that's very important. The incorporation and promotion of biodiversity into the system components and its surroundings and that's what makes for biological pest control, pollination, and other important services of biodiversity. If all these agroecological strategies are well applied, restoration and conservation are enhanced in agroforestry systems in comparison with conventional agriculture and even more when you are comparing with the degraded landscape.