Grazing in orchards, mutually beneficial vineyards
Cattle grazing serves several purposes. It feeds livestock, regenerates plant and soil health and, when animals graze in orchards or woods, decreases the severity of forest fires by reducing fuel loads.
Agroforestry brings together several agricultural practices that integrate trees into cropping and livestock systems for holistic benefits for the environment, the agricultural economy and society. Silvopasture specifically refers to land that is intensively managed for the upper story, trees, fodder and livestock to produce both tree and animal products.
In order for woodlots to be maintained for a healthy timber harvest, they must be managed for pest infestations, soils and hydrology.
“A challenge for forest managers,” says Mark Batcheler, a Washington State University doctoral student studying agroforestry in the Pacific Northwest, “is that forests need disturbance. ecological for maximum health. Here in eastern Washington, it happens naturally due to wildfires, windfall and disease. Managers must mimic ecological processes. Controlled burns are most similar to a natural process, but pose the greatest risk to human populations. Another alternative is to masticate with machines to chop down felled trees, grasses and shrubs.
One holistic way to provide the ecological disturbance a forest needs for its ultimate health and to add a source of income is to graze livestock in high density for short periods of time.
Batcheler studies how managed silvopastoral grazing compares to unmanaged grazing in woodlands, ungrazed forests and grazed pastures without trees.
“Last summer was very hot and dry across the West,” he says. “I, along with others, have observed that the grass is finishing and drying out faster than normal. This happened whether there were trees present or not. However, we noticed that the grasses shaded by the trees remained greener for longer despite severe drought conditions. The forage quality lasted longer and produced a higher yield under the trees.
The silvopasture provided increased quality and quantity of forage from July through September, which is the driest time of the year in eastern Washington.
Shelter for livestock
Trees also provide thermal shelter for livestock. “You’ve seen it,” Batcheler says, “if there’s a single tree in a pasture, the whole herd is shaded under it on a hot day. It has a negative impact. The soil is compacted, all the forage is gone, and the bare soil contributes to erosion and invasive plant species.
In the silvopature, which contains several trees, the cattle spread out more. This avoids a negative impact on a single tree and a single area. By grazing in the shade, the body temperature of the animals remains lower. They gain weight faster and maintain their physical condition because they are not stressed by the heat.
Silvopastoral practices can also benefit fruit trees, such as nuts and fruits, as well as vines. “Because orchards and vineyards produce food crops for humans,” says Batcheler, “food safety must be kept in mind to keep animal droppings away from food products. However, there is huge potential to incorporate more grazing land for livestock, as the vegetation between the rows has to be managed.
Several wineries employ sheep and ducks to graze vegetation and, in the case of ducks, to control pest populations. “Ducks have been used in vineyards for hundreds of years in France,” says Batcheler. “Most people think that ducks live in your pond, but duck is very good meat. There is a high value niche market for duck meat and duck eggs.
“The beauty of agroforestry is its ability to stack ecological functions and sources of economic income for holistic management. Instead of monoculture – whether timber, pears, grapes, cattle or ducks – under agroforestry management, some can be combined for mutual environmental service. For example, there are sheep grazing in the orchard. Sheep keep vegetation low for easy harvesting and healthier trees, and enrich the nutrient cycle. The trees of the orchard shelter the sheep and the fodder between the rows feeds the sheep.
As wildfires burn the western states, agroforestry combined with targeted grazing can be used to utilize livestock to reduce fire fuel loads.
“Wildfires are happening and will happen,” Batcheler said. “When a fire reaches an area where the understory has been managed by cattle grazing, it is likely to reduce the severity of the fire. This is one of the ecosystem services that livestock, grazed with silvopastoral methods, can provide.
In addition, there is carbon sequestration, maintenance of wildlife habitat, regeneration of soil health, and protection of watercourses from erosion and turbidity. Agroforestry practices become more important as the climate fluctuates and the summers get hotter. Livestock grazing on forests offers more adaptability and resilience to producers, both environmentally and economically.