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Legume Trees with Pods Edible by Livestock

This article is an excerpt from my recently published book Carbon Farming: A Global Toolkit for Stabilizing the Climate with Tree Crops and Regenerative Agriculture Practices, and was part of a series promoting my kickstarter campaign to raise funds to complete the book. You can order a copy and learn more about carbon farming.

This painting by Joaquin Sorolla y Bastida shows sheep enjoying the shade and dropped pods of an ancient carob tree. Courtesy Wikimedia Commons.

Rotational grazing is one the most powerful tools we have to sequester carbon through agriculture. We can increase its carbon-sequestering capacity, and its livestock production power, by adding widely-spaced trees. This practice of integrating trees with grazing is called silvopasture. Studies have shown that in many cases trees actually increase the productivity of pasture beneath them, especially trees that cast light shade.

This article is about a particular kind of silvopasture, where the trees literally drop food to the livestock grazing below. Around the world there are many farming systems that utilize this concept, most famously the dehesa of Spain and Portugal which produces gourmet acorn-fed pork. Here I’m narrowing the focus a bit more, to legume trees that drop nutritious pods to the ground for ruminant livestock like cattle, sheep, and goats. There are “fodder pod trees” like this for most of the world’s climates.

Pods of carob, a tree for Mediterranean climates. Great livestock fodder and edible for humans as well.
Pods of carob (Ceratonia siliqua), an ancient Mediterranean crop. Great livestock fodder and edible for humans as well. Courtesy Wikimedia Commons.

These trees are providing more than just food for animals. Livestock enjoy the shade they provide, especially in the tropical sun. Many of these trees fix nitrogen. Some even have pods edible for humans.

Unfortunately not all of these pods fall to the ground when ripe, some must be knocked off the tree with poles, increasing labor requirements. To my knowledge there has been little or no breeding of these trees for the purpose of feeding livestock. The foliage of many serves as a fodder, and some make excellent firewood as well.

The great majority of these species hail from semi-arid Africa savannahs, but this may in part result from a lack of research in other regions. Surely there are many, many more. Savannahs would be the best place to search for such species as they have coevolved with large grazing and browsing animals. An asterisk (*) indicates pods also edible by humans. Sources: Nitrogen Fixing Tree Association NFT Highlights and World Agroforestry Center Agroforestree Database.

Latin Name Climate Native Range Nitrogen Fixation
Acacia leucophloea semi-arid tropical lowlands Asia yes
Acacia nilotica semi-arid tropical lowlands Africa yes
Acacia saligna semi-arid tropical lowlands Australia yes
Acacia senegal semi-arid tropical lowlands and highlands Africa yes
Acacia seyal arid to semi arid tropical lowlands Africa yes
Acacia tortolis arid to semi-arid tropical lowlands, highlands Africa yes
Adenanthera pavonina semiarid to humid tropical lowlands Asia yes
Cassia grandis humid lowland tropics tropical Americas some
*Ceratonia siliqua Mediterranean Mediterranean no
Enterolobium cyclocarpum     yes
*Erythrina edulis semi-arid to humid tropical highlands Andes yes
*Faidherbia albida arid to humid tropical lowlands and highlands Africa yes
*Gleditsia triacanthos cold humid and arid, Mediterranean, tropical highlands North America no
Newtonia buchananii humid tropical lowlands and highlands Africa no
*Parkia biglobosa semiarid to humid tropical lowlands Africa yes
*Parkinsonia aculeata arid to semiarid tropics and subtropics Americas no
*Piliostigma thongii semiarid tropics Africa yes
Pithecellobium dulce semi-arid to humid tropical lowlands Americas yes
Prosopis africana     yes
*Prosopis alba semi-arid tropics South America yes
Prosopis chilensis semi-arid tropics and subtropics South America yes
Prosopis cineraria arid to semi-arid tropical lowlands Asia & Middle east yes
*Prosopis glandulosa arid to semi-arid, subtropics to cold North America yes
*Prosopis juliflora     yes
*Prosopis pallida semiarid tropics South America yes
Prosopis tamarugo arid tropics South America yes
Samanea (= Albizia) saman semi-arid to humid tropical lowlands tropical Americas yes
Senna singueana semiarid tropics Africa no

Again note that nitrogen-fixing legumes are often likely to escape from cultivation. Always investigate your regional native plant resources first. I’m quite certain that there are tens or hundreds more species that produce fodder pods, as well as many more that drop food of one kind or another to ruminants. For example there are many more species of honey locust (Gleditsia) in Asia.

The pods of Acacia nilotica, from African semi-arid savannahs. Courtesy Wikimedia Commons.
The pods of Acacia nilotica, from African semi-arid savannahs. Courtesy Wikimedia Commons.
Cassia grandis, from the humid tropical Americas. Courtesy Wikimedia Commons.
The North American honey locust (Gleditia triacanthos), a good choice for cold temperate climates. Courtesy Wikimedia Commons.
The sweet pods of mesquite (Prosopis glandulosa), a nitrogen-fixing tree for cold, arid landscapes.
The sweet pods of honey mesquite (Prosopis glandulosa), a North America nitrogen-fixing tree for cold, arid landscapes. There are mesquites throughout the dry Americas as well as native species from Africa and Asia, for highlands and lowlands, arid and semi-arid climates. Courtesy Wikimedia Commons.