Myths and Benefits of Silvopasture for the Organic Dairy

Joshua Greene, director of Education, Trees For Graziers

Silvopasture, the thoughtful integration of trees, livestock, and forages, has found a ready audience in the world of organic dairy. As dairy folk across the Northeast and mid-Atlantic encounter the idea of silvopasture for the first time, many objections are raised and for good reasons. At first thought, the idea of planting trees in pastures seems like a crazy idea. Here are some of the typical first responses we hear:

“My grandfather spent half his life clearing this land! He’d roll over in his grave if he knew we were planting trees on the farm.”

“When I was a kid, we went around with a tractor and a chain for weeks pulling out all the stumps and now you’re telling me to think about planting trees?!”

“You want me to plant trees in my pastures? What if I need to make hay?”

And always this one …

“What about grass production? Won’t my pastures produce less forage if I plant trees in them?”

These objections to silvopasture, and many more, bring up important questions. Dozens of important planning considerations need to be mulled over and carefully thought through while developing a silvopasture plan and before moving forward with a silvopasture planting. However, for the farmers adopting this practice, silvopasture promises a path forward to answer some of the nagging limitations of their grazing systems. Some of these graziers have hit a wall with their grazing or have discovered some limitations in their grazing system that silvopasture o?ers a way around. First, let’s consider some of the myths about silvopasture, and second, let’s focus on some of the benefits of silvopasture that farmers who are planting trees in their pastures hope to realize.

5 Myths about Silvopasture

Myth 1: Silvopasture will reduce the production of forages.

Everyone can see the di?erence between the forage production in a mature woodlot (0%) and an open pasture (100%). But is there a continuum between the two, in which as you add more trees you get less forage production? Not exactly. As one paper puts it, “forage growth does not have a simple relationship to light environment.” (https://agrilife.org/spfcic/files/2013/02/ feldhake.pdf) When it comes to cool-season perennial grasses, the species making up the majority of northeastern pastures, much of the available sunlight is not utilized. Unlike warm-season annuals such as corn, sorghum, and other C-4 pathway grasses, cool-season species peak in production in spring when temperatures are much cooler and the amount of daylight is significantly less than during mid-summer. Multiple studies on this subject at Virginia Tech show no significant reduction in annual forage production in silvopasture. These studies are full of other insights, but an intriguing part of the research related to forage production reveals itself upon closer examination. According to the data, the spring flush produced slightly less forage under silvopasture than the completely open pasture, but the summer slump produced slightly more in the silvopasture—essentially flattening out the seasonal production of forages. Isn’t this what all graziers are looking for in their pastures—a smaller spring flush and less of a summer slump? Silvopastures can even out the forage production through the grazing season.

silvo 1 small

Caption: Silvopastures with taller, open canopies provide dappled shade under which livestock and forages thrive. Photo credit: Gabe Pent

Myth 2: My success rate will be low, and the cows will destroy the trees.

Tree protection has come a long way in the last few years. The days of getting stabbed by barbed wire, installing clumsy tree cages, building large, expensive wooden fences around trees, and fencing out tree rows are out. Bring on tree shelters with fiberglass stakes, polywire, and a dash of aluminum wire, and the job of protecting trees in pastures becomes a much easier, cheaper, and successful process.

silvo 2 small

Caption: A short tree wrap at the base of the trees deters mice, voles, and other rodents from nibbling the bark and girdling them. Photo credit: Joshua Greene

Since rotational graziers already have fence chargers and are spooling out polywire on pigtail posts, the opportunity to protect individual trees with electric spark presents itself. If a farmer is looking for more internal fences on the farm to increase the number of paddocks, adding a tree row could be a strategy to break up a large pasture that requires multiple reels of polywire and several armloads of posts. On the contrary, if the paddock configuration needs to be as nimble as possible, protecting the trees with what is called the “overpass” system is an option. With the overpass system, polywire can be strung along the top of 6-foot tree shelters and stretched tight to the perimeter fence. Then cattle can graze 360 degrees around the trees while each tree is protected by a few wraps of polywire (or better, 17-gauge aluminum wire). Cattle first encountering a hot wire on tree shelters rarely develop a habit of rubbing on them.

Besides innovative tree protection systems, using larger tree stock is another major factor in getting high success rates. Rather than planting 25-cent conservation-grade seedlings, purchasing 3 or 4-foot seedlings for just a few dollars more will give the trees a good head start and significantly reduce mortality. Farms planting larger trees and using tested tree protection systems are routinely getting more than a 90% success rate in their plantings.

(P.S. Don’t forget the vole guards! Small rodents are the real tree killers in pastures. Cattle are more interested in the clover than the trees.)

silvo 3 small — Caption: The overpass tree protection system includes polywire attached to the top of a 6-foot tree shelter with an insulated twist tie and aluminum wire (or polywire) wrapped around the shelter and terminated just above pasture height. Photo credit: Joshua GreeneCaption

Myth 3: The trees will compete with my pasture for moisture.

Perhaps the all-to-common scene of a beautiful pasture with one lonely tree surrounded on all sides by bare compacted dirt gives rise to this myth. But this common scenario is usually a function of intense animal impact rather than trees soaking up moisture. Since livestock are looking for some respite from the summer heat and crowd around the available shade, the concentrated nutrients and animal impact end up killing the forages and often the tree as well. Rather than being a case against silvopasture, this lone tree could be a case for having a few dozen such trees throughout the pasture, giving the grazier the option to rotate through paddocks with handfuls of trees in each. Anecdotally, in high summer, the best pasture can be found under the trees where there’s some protection from the intense summer heat and the morning dew has a couple of hours to soak in rather than getting cooked o?. Forages, and not just cattle, perform better under dappled shade. In the Northeast, rainfall is less a limiting factor for pasture growth than the intense summer heat which triggers dormancy in cool-season grasses. We can often see this interaction in our yards where many of us have created mini-silvopastures with a few shade trees and lush lawns.

In the publication Defining Silvopastures: Integrating Tree Production With Forage-Livestock Systems for Economic, Environmental, and Aesthetic Outcomes, the authors put it this way:

Tree-forage interactions are often assumed to reduce soil moisture and nutrients for at least one of the plant types. However, the nature of these interactions depends on multiple factors, including tree species, planting density, spatial arrangement, aspect (the direction the slope faces), soil type and depth, tree and forage rooting depths, and tree and forage water and nutrient-use e?ciencies.

Source: https://www.pubs.ext.vt.edu/CSES/CSES-146/CSES-146.html

Authors: John Fike, Adam Downing, and John Munsell

Myth 4: It’ll take 15 years to get any meaningful shade.

Planting a mix of fast-growing and slow-growing trees has been the chosen tree pattern for many dairy silvopastures. Early successional species such as tulip poplar, black locust, and basswood can be mixed in with some longer-lived, slower growers like oaks and hickories.The right tree planting pattern can reduce the wait for shade as many of these fast-growing trees want to shoot straight and tall, producing shade in a couple of years. Adding in some hybrid willows to wet areas and hybrid poplars to some less soggy soils can shave even more time o? of the wait for shade. Dairy farms that are only concerned about creating shade would do well to plant entire pastures with early successional species, but with a mix of at least three species for diversity.

Myth 5: My neighbors will think I’m crazy if I plant trees in my pastures.

Actually this is one myth that we can’t debunk. People planting silvopasture have no more control over their neighbors’ opinions than the next person. If your farm has been known for doing some unconventional things, a pasture with trees planted in it might just confirm your neighbors’ suspicions about you. !!

5 Benefits of Silvopasture

Benefit 1: Silvopasture in strategic pastures can help to achieve dry-matter intake requirements during the grazing season.

Trying to hit that 30% dry matter intake target is the focus of many organic dairies. Just because there is available forage in a pasture doesn't mean the cattle are comfortable grazing in it. More than likely, the herd is looking for shade by 9 o'clock on a July morning. If the cows have a lane way back to the barn and the gate is open, they will tend to wander back on sunny mornings as soon as the temperature begins to rise. Under dappled shade, however, the cows can comfortably graze longer into the morning. For some dairies, grazing another hour or two each morning can tip the balance and help hit dry-matter intake requirements through the hottest months. For all-grass & forage dairies, the need for pasture intake only increases, as does the need to provide shade for cattle on pasture.

Benefit 2: Silvopasture can reduce heat stress on cattle.

Most dairy folk have seen the impact of heat stress on the dairy herd in the bulk tank. While all classes of ruminants have a reduction in performance in hot weather, it is the dairies who get a twice-daily report from the cows and are much more attuned to the e?ects of heat stress on cow comfort. Not surprisingly, silvopasture for the purpose of improving animal comfort is the number one benefit farmers are seeking from silvopasture.

While the shade mobiles can work to take the edge o? of the heat stress, the extra labor required to drag them around seems like one task too many for busy dairy operations. Many farms have unused shade structures parked in a hedgerow.

Benefit 3: Silvopasture can improve nutrient distribution across the farm.

Cattle love trees … that cool shade, branches overhead to distract pesky flies, and the greener richer forages underneath. Silvopasture creates that perfect microclimate that moderates the temperature for both cattle and forages. The barn certainly works to provide shade for the herd, but providing shade in the barn comes with associated costs. If the dairy herd can be kept comfortable out on pasture during hot spells, many of the tasks around the barn can be kept to a minimum, reducing fuel and labor costs to clean out and stack manure, apply fresh bedding, etc. But besides just reducing labor, the cattle are applying nutrients back to the pastures where they need to be. Silvopasture on hilltops, ridges, or unproductive pastures can be a part of a long-term strategy to drag nutrients upslope where they are needed most, bringing nutrients from the bottomlands up to the naturally poorer, thinner soils on the hills.

silvo 4 small — Caption: A cool-season pasture with 40-feet between-row and 20-feet in-row spacing will soon o?er shade for livestock. The polywire connecting the tree rows can be seen in the foreground. Photo credit: Joshua Greenen

A further nutrient distribution benefit of silvopasture is the di?erent zone that tree roots occupy compared to forage root systems. Consider the following from Fike, Downing, and Munsell:

Trees can also improve nutrient cycling in pastures by accessing nutrients deep in the soil and moving them to the surface via roots exudates and leaf drop. Trees can also increase the system’s nutrient-use e?ciency by capturing nutrients such as nitrogen that are readily leached below the forage rooting zone, and this, in turn, supports more rapid tree growth.

(Source: https://www.pubs.ext.vt.edu/CSES/CSES-146/CSES-146.html)

Benefit 4: Silvopasture can improve soil health by more evenly distributing animal impact.

Farm that have one or two pastures with shade find that they bring the cows to these areas quite frequently. The number of weeks during the grazing season with intense heat seems to outnumber the pastures with shade. This situation leads to more impact on those areas and a lack of adequate rest periods needed for the pastures to fully recover. The long-term e?ect of strategic silvopastures on the dairy farm is an ability to manage animal impact and animal comfort at the same time, leading to improved soil health across the farm.

Distributed, dappled shade gives graziers another tool in the ‘grazier’s toolbox’ (term by Sarah Flack) with the ability to pasture cattle comfortably during heat waves.

silvo 5 small

Caption: The dairy herd at Springwood Organic Dairy in Kinzers, PA grazes around the trees in a planted silvopasture. Photo credit: Joshua Greene

Benefit 5: Silvopasture offers a range of benefits that farmers value beyond the needs of the dairy herd.

Improved wildlife habitat, firewood, fence posts, fruit for the homestead or poultry flock, and a beautiful view are a few of the additional benefits that lead farmers to adopt silvopasture. For those already looking for ways to add shade to the dairy pasture, these additional benefits can add diversity and interest to the farm and also lead to opportunities for stacking enterprises on the farm.

Perhaps some of the benefits of silvopasture could address the needs of your grazing system. If so, reach out and we’ll work together to develop a plan to take your grazing to new heights.

silvo 6 small

Caption: Organic dairy heifers rest on both sides of a tree row protected by the overpass system at Greene Kitchen Farm in Bloomsburg, Pennsylvania. Photo credit: Joshua Greene