by Deborah Jeanne Sergeant
Growing trees for fodder can affect the health of the environment and a farm’s livestock, according to Steve Gabriel of Wellspring Forest Farm and Cornell Small Farms Program. He presented “Tree Fodder for Livestock Health and Carbon Sequestration” as part of the NOFA-NY virtual conference.
A big believer in silvopasture, Gabriel began developing tree fodder in 2016 to support his livestock during a drought. In addition to seeing through his animals, tree fodder also benefits the environment by growing trees in areas meant for grazing.
“Agroforestry is a relatively new term coined in the ‘70s but describes styles of stewardship of land that’s longstanding,” Gabriel said, noting that indigenous tribes have long since used various methods of agroforestry and silvopasture to feed their animals.
He thinks of silvopasture as ecological restoration for livestock habitat. He combines his background in forest ecology with his experience in farming to provide a habitat that benefits both his livestock and the environment. On his farm of sheep and small ruminants, he has created a microhabitat where the animals “encounter something new and unique that feeds their nutritional baseline and their curiosity and natural instincts to seek out food,” Gabriel said.
Silvopasture may be created by converting woodland into a space that includes livestock or adding trees to an existing pasture. With existing woodland, it involves opening up the tree canopy so that sufficient light reaches the forest floor. With the existing pasture, adding shade, shelter and fodder are the goals.
Gabriel views silvopasture as a means for farms to build resilience and to sequester carbon. He noted that trees and forests are 80% above ground carbon, build fungi networks and are slow and stable growers. Grasslands are 80% below ground carbon and are fast and more volatile growers.
“The beauty of the grasses is they have a rapid mechanism to put carbon in the soil, and when we add trees, we have another long-term storage of carbon,” Gabriel said.
He explained that root fungi store a surprising amount of carbon sequestered in the soil. “Grassland ecosystems are low in fungal communities. But adding trees increases fungi and fungi bring carbon,” he said.
Differences between operations matter in carbon sequestration. “There’s variability of the capacity of a given site,” Gabriel said. Clay soil, for example, has a better chance to sequester soil than a site low in clay.
“What we’ve been working on is looking at the potential for tree planting on farms and what it can do,” Gabriel said. “We have a small amount of carbon sequestered when trees are young that increases exponentially.”
He is working on research to show farmers the merit of planting trees as a means of offsetting their carbon output while providing other value to the farm.
Gabriel’s farm’s main crop is mushrooms. He also rents lodging, makes maple syrup, raises pastured lambs and nursery trees and provides education and agritourism. When he began farming on his current site, about 20% of the land was overgrown with thickets. He raises a breed of sheep that grazes in goat-like fashion so he fenced the hedgereows and let the flock at the overgrowth.
“We were a little scared about them eating things that would make them sick,” Gabriel said. “They have an incredible ability to step into the environment and make good choices.” He was able to sustain them 45 days on woody vegetation, partly by helping the animals reach more vegetation with loppers and a chainsaw.
Eventually, Gabriel created berms to regulate the flow of water on the farm and since he had disturbed the soil to create them, he began planting willow and poplar. By the time a drought hit, his willow trees were five years old. When he began feeding the livestock with the willows, he noticed that they would eat for a while and then back off. He learned later that the secondary compounds in willow, such as tannins, slow digestion and help the animals digest more woody materials. They also lower methane and reduce parasites.
He’s also used trees to weave “living fences” to keep his animals contained. While they may eat some of their “fence,” they will not eat their way out of confinement. Plus, “it’s a fodder bank for these animals,” Gabriel said. “They eat a certain amount of this but we move them every day … Willow buffers also sequester carbon. These are the kind of stacking benefits we want to happen on the farm.”
When considering trees to plant as fodder, he looks at the nutritional content over the seasons; the best species to use for multiple yields; tolerance for grazing and recovery period; initial establishment; systems for managing a substantial forage; and animal familiarity and willingness to eat (but not overeat to toxicity).
He began to research willow, black locust, poplar and mulberry, as each of these grow on his farm. These are all appropriate for his temperate/cold climate and are fast-growing trees. He discovered that willow and poplar are similar to grasses nutritionally. Black locust offers high protein as the “tree alfalfa.” Mulberry is highly digestible and offers fruit that appeal to other livestock, like pigs and poultry. Black locust is nitrogen fixing like a legume and if it grows long enough, it can be harvested for fence posts as its wood is rot resistant.
While his animals seemed willing to consume the trees he planted for fodder, he needed assurance that they were nutritionally sound for consumption. To answer that question, he sent samples in for lab testing through a SARE research grant. He looked at willow, poplar, black locust, Japanese honeysuckle, European buckthorn and wild cherry. He collected 120 random samples in 2019 and 2020 from multiple trees.
“All of them offer really great nutrition,” Gabriel said. While the amounts of various nutrients differ, “it’s clear these plants have some substantial nutritional contributions to the animals’ diet.”
Willow provides high levels of zinc, calcium, magnesium and manganese. For poplar, it’s zinc, calcium and manganese. Black locust offers protein, potassium and energy; Japanese honeysuckle, calcium, magnesium and energy. European buckthorn is rich in protein, potassium, calcium and iron. Wild cherry provides manganese and calcium.
Of course, trees grown on one site may have different nutritional values than trees grown on a different site. “It’s dangerous to extrapolate the data and say, ‘This is what will be the nutritional value of the trees on my site,’” Gabriel said. “It varies site to site. Don’t take it at face value. It’s very site and season specific. If you want to dig in and do it on your farm, you’d need to do a fodder analysis.”
Feeding trees as fodder may not be part of a farm’s nutrition management plan every year; however, that does not deter Gabriel.
“Last year, we barely fed any tree fodder as it was a very wet year,” he said. “But all that growth is in forage for the next time it’s dry and we don’t have forage. We can have that stuff ready for the next time we need it.”