Whether you call it a silvopasture, savanna, or woodland, here at Hamilton Native Outpost we have been establishing them for 20+ years and want to share some lessons learned. The results are excellent wildlife habitat, improved soil health, and, when grazed well, a sustainable pasture with high quality forage.
Silvopasture (a combination of the Latin word, silva, meaning trees and the word pasture), savanna, and woodland are roughly equivalent terms in that they signify a grassland scattered with trees. The tree plus grassland ecosystem is exceptional habitat for wildlife, and it is quite pleasing to the eye in its park-like appearance. Grazing was historically a part of these grass plus tree ecosystems, which were once quite common. Thus, grazing is a natural fit, and having trees interspersed on a grassland makes it more pleasant for the livestock on a hot summer day or a blustery winter day. In our estimation, creating a silvopasture is a great way to turn nonproductive land into something productive (e.g. a rocky, wooded, south facing hillslope that will never produce very good timber) or with VERY careful management actually be able to harvest a tree crop as well as forage off of the land. It is also possible to take a piece of land that has been logged hard and will not produce timber again for a number of generations and begin producing valuable forage within a couple years.
Early spring forage provided by Early Wild Rye growing in a woodland.
In general, the process is to start with a forested site, in other words a site where very little sunlight gets to the ground because the sunlight is caught first by the tree leaves above. Then, the trees are thinned by any number of methods including (but not limited to) a timber harvest, hack-and-squirt (also called hack-and-treat, this is basically girdling the tree and applying herbicide to the girdle), or even sometimes a dozer or tree masticator/shredder/mulcher. Following thinning a seedbed is prepared and native grass and wildflower seed is sown. Here are 9 tips that examine this process in detail:
1. Remove plenty of trees. The exact percent can be a little bit variable, but the concept is that grassland plants don’t like to grow under a dense canopy of trees – they need plenty of sunlight. We often aim for 30-50% shade because we feel this is a good balance with the forage production. While the grassland plants might be okay with 60% shade, keep in mind that 60% quickly turns into 70 and 80% as the remaining trees enjoy their newfound freedom from neighbors and go through a growth spurt.
Tree shape matters. Trees that are shaped like a stalk of celery, that is a long trunk with a few leaves at the very top, grew up with lots of competition, and because they had to chase sunlight and outcompete their neighbors they grew straight and tall so as not to be overshadowed by the neighboring trees; they are not adapted to growing by themselves, and when their neighboring trees are removed they are often too weak to stand alone. Rather, trees that grew up without as much competition and resemble a good Christmas tree, that is to say it has limbs up and down the trunk rather than all at the top, are better adapted to a more open environment. If possible, leave the trees with a more open-grown form, sometimes these trees are quite old, but sometimes a younger tree is developing in a void and still has the open-grown form. When possible try to leave younger trees that have a good shape so that there is a mixed age of trees instead of only big, old trees. In situations where only the “celery trees” exist, it is usually not desirable to thin as much (maybe just down to 50% shade), but this means more frequent subsequent thinnings may be required.
Tree shape varies greatly. (A) is a tree with a spherical shape that has grown in the open its entire existence and is a great choice for a silvopasture. (B) is a tree that once grew in a more open setting than it does today as evidenced by the major fork in the trunk about 2/3 of the way up and the lower branches that have died from lack of sunlight in more recent times; it is also a great tree to leave in a silvopasture while the trees to its right would be poor choices. (C) are trees left after a timber harvest, and due to their long, tall, skinny trunks with a few leaves at the top, they are not adapted to growing in the open and likely will not survive. (D) shows an understory tree that is unhealthy as it cannot get enough sunlight, and in its search for sunlight has a crook in its trunk toward the top.
3. Cows don’t care about stumps and a few limbs, should you? Depending on your thinning method, stumps may remain in the field. Decide if stumps and scattered limbs need to be removed. Removing stumps is usually costly, and cows can walk around them just fine. So, in many cases it is best to just leave them. However, if you plan to brush hog or just can’t stand the look of a field with stumps in it, stump grinding is an option.
4. Consider fire. Fire is a natural part of savanna and woodland ecosystems. Consider if you want to use prescribed burns, either in the establishment phase or in the maintenance of the silvopasture. Even if you are not the one to light the match, fire may still need to be considered because wildfires do happen. In planning for fire, consider these thoughts:
Fire is a useful tool. Learn to use it well so that the trees are not unintentionally harmed, and it is safely carried out.
5. Get in and get it done. Once you cut or deaden the first tree, keep the project moving. From thinning to seeding, the timeframe is usually less than a year. When developing a timeline keep in mind that seeding must happen in the winter and seedbed preparation usually begins in early fall. If the project is too big to keep on this time frame, split it into manageable chunks. If there is a significant time lag before planting, brushy plants, resprouts from the cut trees, early successional plants in the seedbank (e.g. broomsedge), and even invasive plants (e.g. multiflora rose, Himalayan blackberries, sericea lespedeza) get a head start and provide significant competition to developing seedlings.
6. Get the right plant in the right place. To begin, some people ask if they even need to plant seed. We have done it both ways and have found that seed will increase the speed with which establishment happens and give much better diversity of plants. Often entire groups of plants (such as warm season grasses and even many cool season grasses) do not come back; it seems that hard-seeded plants often return because their seeds can remain viable in the seedbank for a long time. Also, it appears that sometimes, due to past mismanagement of a particular area, palatable species of plants were grazed out by overgrazing and do not return. When seeding an area, make sure to choose an adapted group of plants. An obvious example of adaptation is that a cactus will not thrive in a wetland while a cattail will not appreciate a dry, rocky ridge. So, consider the soils, and choose species adapted to the site’s soil moisture regime. The amount of shade present will also influence choices (e.g. native cool season grasses such as the wild ryes and river oats are designed to do better in low light situations than the native warm season grasses such as big bluestem or eastern gama grass). And, speaking of warm and cool season grasses, which are different functional diversity groups of plants, make sure to include plants from both groups as well as forbs and legumes because the diversity will improve forage production, wildlife habitat and soil health. Read more about how diversity makes a grassland green in all seasons, puts roots in all depths, creates a situation where plants help other plants get water, and how the functions of different root systems complement each other.
7. Ensure seed-to-soil contact. Seed that falls onto a tree leaf will not turn into a plant. So, make plans to get seeds into contact with the soil; this is very important! We have found that two disturbance events are needed before seeding. One option is that between early fall and about January 15th, plan to burn twice (once before leaf drop and once after). Another option is to burn once and then use the hooves of cattle to disturb a second time. Cattle can be fed hay or grain in the area to get this disturbance; however, caution should be taken that the hay or grain is free of weed seeds. Most readily available hay is harvested when viable seed is present and should not be used; however, alfalfa hay can be a good option if careful measures were taken to control the weeds in the hayfield. Dried distillers’ grain is an excellent grain choice as its processing has killed any weed seeds. Hay and grain are big vectors of weed travel so take caution when feeding them on a native grassland of any type.
8. Use an aerial spreader. There are a few options for seeding silvopastures. Usually mechanical options such as a tractor and broadcast seeder or drill are not good options due to the stumps and limbs in the area, or in the case of hack-and-squirt, the fact that the trees are too close together to drive a tractor. Seeding by hand is an option, and we have done many acres this way, but it is a bit discouraging in that it takes about 1-2 hours to seed 1 acre, and the coverage is often a little spotty. Because of the laborious options we have spent many hours doing, we at Hamilton Native Outpost recently developed a spreader that fits on a drone with silvopasture seeding in mind. The drone doesn’t care about standing trees, stumps, down trees or even ground that is too steep or wet to get a tractor on as it zips back and forth above the treetops. See videos and learn more about this aerial spreader.
9. Get a plan for resprouts and brush. Most tree species will sprout back after being cut down (cedars are a notable exception because when cut below all greenery they will not sprout back), and many species of brush or understory trees (e.g. redbuds, multiflora rose, sumacs, poison ivy, blackberries) are waiting for enough sunlight to establish. Get a plan to deal with this; options for control include:
A well-shaped tree in the middle of a grassland is a beautiful sight.
Watch as Joshua Cooper of Brown Hill Cattle Company talks about the process of creating a silvopasture and his anticipation of combining quality forage with quality wildlife habitat in the video above. Or, watch the below video to see the aerial spreader go to work seeding seeding overtop of the trees in the silvopasture.