Six Key Principles for a Successful Silvopasture
Within the practice of agroforestry, or mixing trees with agricultural production, the concept of silvopasture has some of the broadest appeal. Many farms already work with livestock, and making good use of forested land for multiple yields is highly beneficial to the farmer.
Whether you choose to graze sheep in a christmas tree farm, move cows through a walnut plantation, or graze chickens though an apple orchard, several key principles apply. In reading about silvopasture, you will see again and again that that system is not just “throwing animals” into the woods, or planting some trees in the pasture. There must be thought, planning, and intention as the farmer designs the system.
1. Silvopasture can be established in existing woodlands, or trees can be brought into pasture
One of the nice aspects to silvopasture is that one can establish a system on almost any type of land. Of course, establishing it in existing forest is a very different process in many ways than bringing the trees into open pasture. The similarities and differences of establishment in such different contexts will be discussed at length in the book. The only land types we might consider avoiding silvopasture are very sensitive areas such as wetlands and healthy, maturing hardwood forests that might be best left to their own process of succession.
If starting with forest, the farmer needs to change the ecology to support establishment of forages, which include grasses, legumes, forbs, and shrubs and trees meant as fodder for livestock. Trees could also produce fruits and nuts for foraging, such as chestnuts or persimmons, which animals could harvest once they fall to the ground.
In the pasture, the goal is to add trees without blocking too much light from hitting the ground, which could supress forage growth. Trees can be planted in rows, clusters, or evenly spaced in a orchard-like planting. Fast growing species such as locust, alder, willow, and poplar offer an advantage because they can quickly grow above browse height, which allows for faster integration.
In any case, a balance has to be struck so that all parts of the system are optimized. Remarkably, research has shown that some pasture grasses actually perform better under partial shade. Less suprising is that animals also do better, benefitting from the cooling effects of shade, especially in the hot summer months.
2. Animals are matched to land type and stage of succession
It’s critically important from the outset that the appropriate animal is chosen for a given site in order to reduce the potential of inflicting damage to the landscape. Animals are incredible at what they do, but it cannot be overstated that they have just as much potential to do good as they do harm. While we will cover considerations for specific animals in depth in the book, here is a general list of the potential risks for a given species:
Cows: excessive stocking/duration with their weight could damage soil, tree roots, and cause erosion, also prone to easily destroy young trees
Pigs: could root and trample desired vegetation and make a moonscape of your woods or pasture in a very short about of time
Sheep & Goats: depending on forage type could overgraze the landscape and/or strip the bark off young trees, killing them
Poultry: could scratch or root down to bare soil and damage roots and plantings
Animals can do a lot of good, or a lot of harm. You can see from the above list that most of the problems can be avoided by doing proper assessment of the land and engaging with the animals to ensure they are moved before doing harm. Design revolves around determining how many animals are in a paddock, for how long, and vary widely depending on the season, microclimate, and several other factors.
In addition to choosing the right type of animal for the system, careful selection of the specific breed is an essential task. Some breeds are able to utilize a wider range of forage and conditions, whereas others are not as willing to be as flexible. Often, farmers can have success “training” animals to be better browsers on a range of forage, if they are not accustomed to seeking it out.
3. Animals are always on a rotation
This principle is implied above, and proper rotation of animals has been shown to have a myriad of benefits to a farm. Moving animals allows for a given paddock to rest and recover, which is critical to maximizing forage quantity and quality. Moving animals is good for them, as well, as they have reduced exposure to disease risks and are receiving the highest quality food possible.
This aspect of silvopasture is NON-NEGOTIABLE, and is often the biggest hurdle for adopting the practice, especially by grazers who have been practicing continuous grazing (leaving animals in one large paddock) for some time. Regardless, it is the universal opinion of silvopasture advocates that animals should not be placed in tree-based systems if they will not be managed through rotational grazing.
4. Trees should match the soil type and microclimate and have multiple functions
One could arguably plant trees for the sole purpose of shading their livestock, but why not aim a bit higher? There are so many choices in the temperate climate for trees that will do well in even the worst of soils that provide not only shade but a number of other possible yields. Of course, the yields will depend on how the trees are managed, and are easier to “control” when establishing a silvopasture in open field conditions versus an existing forest.
The goals of the farmer or landowner also come into play, as there is not use planting apple trees, for instance, if there isn’t a desire to harvest apples. Some farmers want to establish the lowest maintenance trees possible. Some want a yield of fruit in 3 – 5 years or of nuts in 5 – 10. And some are happy to plant timber species and wait 50 or more years to harvest.
A few of our favorite silvopasture species include:
Black Locust (Robinia pseudoacacia) is hardy, reslient, and produces some of the most rot resitant wood in the temperate climate while also offering high-protein fodder for animals
Alder (Alnus spp.) are the best trees at fixing nitrogen in the temperate climate. They offer high protein fiber for animals, decent firewood, and even logs for mushroom cultivation.
Willow (Salix spp.) are a huge genera of trees that are highly adaptable and produce condensed tannins that have been shown to reduce some parasite loads in grazing sheep
Chestnut (Castanea spp.) are fast growing (for nut trees), highly productive, and nut bearing species that works well with grazing livestock.
Black Walnut (Juglans nigra) offers one of the most valuable timber species worldwide as well as nutritious nuts, and has a long track record of success in silvopasture systems
5. Forage and fodder should be diverse and support a resilient food supply for animals
One of the largest opportunities in silvopasture is the creation of a wide range of ecotypes, which can support a wider range of grasses, forbs, herbaceous plants, and trees for animal feed. This gives animals a more diverse and healthy diet that is not only nutritious, but potentially medicinal. In essence, the design of a diverse silvopasture offers animals a habitat that might resemble their “original” experience grazing in the wild.
Farming has oversimplified the animals experience of seeking food; in some operations the animals only visit the feed bin for grain or hay. This not only offers a limited diet in terms of nutrition, but starves the animals of needing to exercise their innate characteristics for seeking out food in the landscape.
In addition to supporting overall health and well-being of the animals through diverse forage, this focus provides an economic incentive for the farmer. More diverse feeds should reduce the feed bill and also provide food in lean times, as tree-based systems can often buffer better against long-term drought and even excessive rain. Since grasses grow on a bell curve, they often “peak” in early summer and production is lower in July and August – unless the forages are shaded and can thus sustain better quality for a longer period of time.
Careful matching of forage to these micro-environments is the challenge. For example, for most silvopastute in the eastern US, cool-season grasses, also know as F1, are utilized, as they excel in part sun environments. Warm season grasses are best for overly sunny or dry areas, or warmer climates. The trees effectively help keep the optimal conditions for the cool season grasses throughout the summer months. This, coupled with the careful selection of trees that leaf out at various times and provide a range of shade conditions, can optimize production.
For instance, Black Locust is a great silvopasture species as it leafs out late in the spring and when fully leafed out casts a mild shade, allowing the space underneath to be cool and somewhat shady, but not to the point where grasses would be stressed for light.
6. The system is optimized to stack inputs and outputs in both space and time
The beauty in silvopasture systems is not in the parts, but the complex whole that is created by these systems. Yet, with complexity comes a challenge in management – this is indeed why agriculture in the US and other industrialized nation has been on a trend for more straight rows, single species monoculture, and rationed feeds. It’s easier to do the math. But as we will discuss in the book, the benefits of creating a more complex ecology outweigh the perhaps more difficult time it takes to design, establish, and manage such a system.
Being patient is key. Few of us are raised in a culture where we understand a more natural way of farming. Many are interested in the concept of a more complex ecology, yet find themselves overwhelmed and frustrated as they try to comprehend and understand things. It’s wise then, to start small and slow, especially if you are new to one or more of the two main aspects of this practice (grazing and forestry).
Draw upon the knowledge of others, and recognize you are in for a lifetime of learning. Get the foundations of grazing right from the start, then bring in the forestry aspects. The content of the book, along with the case studies of farms actively practicing silvopasture, will help paint a picture of how this can be done.