by Tamara Scully
Silvopasture is the managed integration of trees and livestock, utilizing the land both to produce a tree crop and to graze livestock. This multi-tasking can result in diverse income streams, with money from timber, nuts, syrup or other tree by-product, plus income from livestock production. Silvopasturing enhances both systems: the forest and the animals. It is one of five recognized agroforestry practices in the United States.
Unmanaged woodland grazing can be extremely detrimental to the ecosystem, and may not add any value to a livestock production system. A few scattered trees in a pasture can cause more harm than good. But neither of these scenarios represent a silvopasturing practice.
Trees in a silvopasture system are managed to create a basal area density which promotes forage growth, and allows for optimal growth of the forest crop as well. Trees can be in rows, or clustered. Livestock presence is managed, to prevent soil compaction, overgrazing, manure buildup and damage to the forest ecosystem.
For a livestock producer, there are many good reasons to add a silvopasture component to an existing grazing system. Whether planting trees on pasture, or incorporating existing woodlands into pasture boundaries, livestock producers are finding that silvopasturing benefits the animals, the farm’s productivity, and the bottom line. Using existing, underutilized wooded areas of a farm is also a smart way to increase the value of the land, and the carrying capacity of the farm, without investing in new land. With a dwindling land base and high land prices, as well as an interest in maintaining healthy ecosystems, the interest in silvopasturing techniques in the Northeast is growing.
Grazing and silvopasture
Faye Benson, of Cornell University’s Small Dairy Support team, has custom-grazed dairy heifers for the past five years. Benson grazes year-old heifers for Walnut Ridge Dairy, in Lansing, NY. The heifers are pastured beginning in May, on a total of 90 acres. Benson uses rotational grazing paddocks, each six acres in size, which can be broken into smaller segments as needed. The animals move as one group, and are moved every day or every other day, depending on conditions. Benson grazes approximately 60 heifers each season.
Benson became interested in providing the animals shade after conducting research, under a USDA SARE grant, in 2009-2010. He researched the effects of placing dairy heifers on pasture compared to keeping them in confinement housing. As a part of this study, Benson tracked the movement of the heifers using pedometers attached to the ankles of the animals. Since Benson’s previous studies had demonstrated a cost benefit of grazing, his goal was to show that grazing caused no decrease in future health or productivity, and to convince dairy farmers to graze their dairy herd replacements during the grazing season.
During this study, Benson found that confinement animals walked less than one mile per day, while pastured heifers walked approximately 2.8 miles per day. The results of the study led Benson to track the movement of the heifers on pasture and correlate it with the temperature. He found there is an inverse correlation between heat and movement, with hotter days leading to less movement. He decided that adding shade to a grazing operation could help to keep the cow’s moving.
The standard daily gain of the heifers Benson grazes is 1.75 pounds. This gain is typically achieved on pasture forage for most of the grazing season, Benson said. In order to maintain that gain, Benson is interested in implementing paddocks which provide shade, to be used during the hot summer days, particularly when the temperature is above 90°F.
Several previous studies have shown that milk production, weight gain an fertility are all positively impacted when shade is made available to grazing cows, according to Brett Chedzoy, a forester with Cornell Cooperative Extension of Schuyler County. Chedzoy implements silvopasturing techniques on his family’s Watkins Glen, NY farm, Angus Glen Farms, LLC.
Chedzoy recently led participants on a pasture walk and silvopasturing overview at Benson’s farm in Groton, NY. Following a lunch, the group was taught to measure the basal stump area in wooded ground at Benson’s farm. The existing basal area of 120 square feet/acre is too dense for silvopasturing, as adequate forages will not grow in that degree of shade. In order to utilize the wooded area for silvopasturing, Benson will need to reduce the tree canopy to let the sunlight reach the ground. The target basal area for livestock forages of cool season grasses and forbs is 60 square feet per acre. The basal area is the surface area of all tree stems at 4.5 feet above the ground. An angle gauge is simple instrument which was used by participants to manually calculate the basal area.
Once selected trees have been removed, Chedzoy recommends grazing start immediately. Otherwise, unwanted brambles and weeds will have the chance to quickly establish themselves. Managing the land for the production of the desired forage may not require seeding, as land adjacent to existing pastures may see forage establishment occur naturally. Grazing practices in wooded areas are rotated with a longer recovery period than is typical for pasture, as regenerative growth will be slower. Also, if the area is being managed to allow woody plants to become established, less frequent use, to allow plant recovery time, would be necessary.
On Benson’s farm, the silvopastures will be used to provide shade in time of high temperatures. The objective is to keep the amount of grazing steady, and to retain the average daily gain, even during periods of high temperature. Benson will develop several silvopasture paddocks, whose use will be closely managed to benefit animal comfort and performance. The paddock access gates will be on a timer, and will allow the animals entry only during the hottest part of the day. Benson will then move the animals out of the silvopastures in the evening.
In this manner, Benson can control the shaded paddocks to avoid overuse, manure buildup, soil compaction or other issues of concern. By providing the cows with shade for comfort, while promoting grazing on the silvopasture forages, Benson should be able to retain his average daily gain, increase animal welfare, and better utilize his existing acreage.
Several silvopasturing workshops have been scheduled by Cornell Cooperative Extension. These will occur in Pennsylvania, New York and New Hampshire, and details will be posted on the web at: www.silvopasture.ning.com