Silvopasture is the intentional integration of tree crops and/or timber trees in grazing systems. The trees may be original to the landscape or planted. However, allowing livestock to graze in existing forest is often poorly planned and managed, and damaging to the ecosystem.
Wood pasture farming usually involves livestock grazing on permanent pastures with a scattered tree cover. Traditional management of wood pasture maintains a characteristic landscape containing elements of woodland, cropped and fallow land, species-rich grassland and scrub. Small areas of cereals may also be cultivated (in rotation with fallow and pasture) to provide supplementary forage for the livestock.
Using electronic mobile fencing, farmers move their animals from one area to another, sometimes every day or two, to avoid compacting the soil, causing erosion, damaging surface roots and trees and killing the grasses and pasture plants by grazing too intensively. Plants need time to regrow, and as they do, they continue to photosynthesize, sequestering more carbon and increasing soil fertility and water retention. Rotational grazing mimics the movement of wild herds, closely grouped for protection, nibbling, leaving their valuable waste and moving on. Both the animals and the soil benefit. In mixed pastures of trees, grass and other plants, animals choose the forage their bodies require, reducing disease and parasites. Shade in summer reduces stress leading to greater weight gain and increased milk production.
This mixture of habitats contains a remarkable abundance and variety of wildlife, and is especially important for breeding birds, and as a wintering ground for migratory species.
Thirty-nine species of shrubs and trees are browsed by Fulani pastoralists' cattle in two areas of central Nigeria, many of them indigenous economic trees. The native pastoralists are very knowledgeable not only about the plants' relative abundance but also their nutritive value.
The Pokot and Turkana people of Kenya and the Sukuma people of Tanzania also use agro-silvo-pastoral systems which display a rich and detailed local knowledge base as it relates to the environment and ecology. This comprises a detailed ethnobotanical knowledge as it relates to species utilization and their management, which is then related to broad land management systems which, especially in Pokot and Turkana are both environmentally sound, ecologically viable and culturally acceptable. However, such systems and knowledge bases are not more widely utilized. This relates to traditional conservatism and constraints pertaining to such lands. Ways are being developed as to how the people and the traditional knowledge base can be brought into the focus of development and change, particularly in the silvo-pastoral context. This is based on a participatory sharing extension approach which identifies potential and constraints in the traditional base combined with problem identification and solution finding. The example of the Turkana Rural Development Programme's forestry shows how this can be achieved (or at least partly so) in a large district such as Turkana whose people are mobile and widely spaced. Such work can fit into current day development thinking as a means of relating the local knowledge base to the present day.
The multi-species silvopastoral systems of Venezuela are found in the tropical dry forest (savannas) and in the very dry tropical forest of the semiarid zones of the country. A large number of trees and shrubs are found in these pastoral areas where they play both productive (fodder and feed) and service (shelter) roles. Although this system is practised over large areas of the country, practically no research has been done to improve it. In order to strengthen national capability to undertake such research, international support of cash and as well as technical advice is needed.
In arid and semi-arid Africa (including North Africa, the Sahara, the Sahel, the semi-arid parts of the Sudan zone, and the arid zones of southern Africa) the majority of production systems in one way or another rely on livestock (ranging from settled agropastoralists to continuously mobile nomads). Strictly pastoral systems may be defined as any production system that relies for more than 10% of its output on livestock. The main emphasis is placed on the use and management of natural resources, primarily vegetation, but also water and wildlife. Other production systems also rely on resources in their natural state, such as hunting, gathering, fishing and wood collecting.
These wood pastures are called dehesas in Spain and montados in Portugal. The oak trees of the dehesa and montado systems provide shelter for livestock and crops, but are also essential productive components. Acorns and cut branches are used as extra fodder for the live stock and cork is harvested from the bark of the cork oak trees. A multidisciplinary team undertook a six-year investigation on the agro-ecological and socio-economic aspects of the dehesa system in the Sierra Norte area, a part of the Sierra Morena of the Sevilla Province, Western Andalusia, Spain. The synergistic effects of tree cover on understorey grassland vegetation builds soil fertility and favourable micro-climatic and hydrological features.