Agroforestry

Agroforestry is a land use management system that integrates trees with crops or pasture. It is also known as agro-sylviculture or forest farming. This practice combines agricultural and forestry technologies to create a polyculture system. A polyculture is a method where many different species grow together on the same land.

Agroforestry is considered applied agroecology. This means it uses the forest as a model to initiate agroecological succession. This process mimics the way natural vegetation develops over time. By managing these interactions, farmers can optimize the relationship between plants and animals.

These systems are highly productive and diverse. They can produce timber, fruits, nuts, and edible mushrooms. Farmers may also grow medicinal plants, ornamental plants, and various vegetables. Some systems even include animals and animal products.

Because they produce so many different things, these farms provide economic, environmental, and social benefits. This diversity helps increase farm profits and provides food security. It also creates a more beautiful and aesthetic environment for the people living there.

Agroforestry systems can be organized into many different types. Some are simple configurations, such as hedges or trees integrated with a single crop. Others are much more complex. These are called multi-strata agroforests, which can contain hundreds of different species.

A common example is the tropical home garden. These gardens often have a layered structure. The top layer consists of a canopy of tree and palm species. These provide food, fuel, and shade. The mid-story contains shrubs used for fruit or spices. Finally, the understory includes root vegetables, medicinal herbs, and beans.

While the term "agroforestry" was coined in 1973 by Canadian forester John Bene, the practice is ancient. Indigenous communities have managed forest ecosystems for millennia. In California, Indigenous peoples used fire to maintain a pyrodiversity collecting model. This helped improve tree health and habitat conditions. In the eastern United States, Native Americans managed land as a mosaic of orchards and forest gardens.

In Central America, some tropical home gardens have been continuously cultivated for centuries. One such garden might contain 25 different species on just one-tenth of an acre.

Specific scientific ideas have helped shape modern agroforestry. In 1929, J. Russel Smith published Tree Crops: A Permanent Agriculture. He argued that agriculture should use non-arable land for tree crops. He also suggested using tree products to replace grain in livestock diets. He specifically noted the potential of the honey locust tree, a legume, to serve as nutritious livestock feed.

This work eventually led to the concept of permaculture.

Agroforestry provides critical services for the environment. It supports biodiversity by creating ecological niches for organisms above and below ground. For example, tropical bat and bird diversity in agroforests can be comparable to natural forests.

Trees also help with carbon sequestration. This is the process of capturing and storing carbon in soil and woody biomass. This helps mitigate the effects of climate change. Additionally, agroforestry reduces soil erosion. Groundcover plants stabilize the soil, while trees reduce water runoff and evaporation. This improves soil structure and helps keep water clean.

Farmers use these methods to adapt to changing environments. In East Africa, a survey of 700 households showed that at least 50% had begun planting trees to adapt to climate change. They plant trees alongside fruit, tea, coffee, and medicinal products.

In Zambia, research showed that inter-cropping maize with the nitrogen-fixing tree Faidherbia albida can be very effective. Using 25 to 100 trees per hectare resulted in maize yields of 4.0 tonnes per hectare. This is much higher than the average yield of 1.1 tonnes per hectare in Zimbabwe.

This demonstrates how agroforestry can restore productivity to the land.