What Is Shade Worth On Pasture?
By Austin Unruh
This article first appeared in the January 2023 issue of Graze. We're sharing it here in full to give you a taste of the practical content we offer in each issue of the magazine. For the full meal, subscribe today!
When I lay out the benefits of silvopasture to a producer, I like to highlight four key goals: shade, shelter (windbreak), summer fodder and winter feed.
Of course there are other benefits like nitrogen fixation, cycling of nutrients from deep underground, increased soil organic matter and more. But shade, shelter and feed seem to be the biggest boons to graziers.
By and large, what brings most graziers to plant trees is the need for shade. Everyone who runs livestock on pasture recognizes that shade is critical to success. In study after study, livestock are shown to gain more weight, produce more milk and breed more efficiently if they have access to shade.
All these things are good to know, but what any businessperson needs to really know when investing in something like trees is this: will it pay?
To figure that out, we need to break things down into dollars and cents, or at least attempt to. Honestly, there are so many variables that it’s impossible to tell you exactly how much shade is worth for your operation.
The benefit in shade is reducing livestock heat stress, which is dependent on obvious factors like temperature and humidity, but also whether it’s a sunny or cloudy day, how much of a breeze there is, whether temperatures drop at night to allow livestock to recover, the breed, color of their coat, whether they’ve shed their winter coat and many more variables.
As with most things in agriculture, the best answer to “how much is shade worth” would be “well, it depends”. Because that’s not a satisfying answer, let’s take a stab at putting some dollars to this.
Working some numbers
Let’s assume we’re working in the context of a stocker operation where stockers with access to shade will gain 0.89 lbs. a day more than stockers without shade. Those are the numbers from a study in Kentucky back in 1999. The authors of that study note that the maximum temperature recorded during that study was only 84 degrees, and of course many producers will see temperatures consistently above that. So the 0.89 figure will be low for many producers.
Next, let’s assume that every additional pound of gain is worth $1.40. That number will vary based on market values, but it seems reasonable.
Put those numbers together, and every day a stocker has shade means it’s making you an additional $1.25. At least that’s a useful number to start with, and you can adjust up or down depending on your conditions.
Now the question you’ll have to answer is this: how many days would that apply in your context?
That’s going to be determined by the factors mentioned above, such as the temperature and humidity in your area. If you’re in northern Minnesota and might only get 50 days of relatively light heat stress, you’ll have a completely different calculation than someone in Louisiana who might see moderate to severe heat stress for the better part of the year.
If you’re a dairy producer, you may now be wondering how this translates to milk production. I wish I could tell you. It’s tough to find useful numbers assessing the production gains of grazed dairy cows when given access to shade. It seems few researchers have looked into that question. Given the higher metabolic rate of dairy animals, I would suspect that the gains from providing shade for dairy would be higher than the gains for beef.
(Editor’s note: Based on many statements made by grass-based dairy farmers, 5 lbs. of milk per day might be a conservative estimate for milk losses from lack of shade. At $20/cwt. milk, that comes to about $1/day in lost milk income per cow.)
I should mention that trees provide better quality shade than do physical structures. We know this because cattle will vote with their feet and almost universally prefer to stand under the shade of a tree than under a portable structure. I’ve been told so by countless farmers.
Plus, the benefits of tree shade are backed up in trials. Researchers at the University of Arkansas tracked weight gain for dry Brangus cows and found the following average daily weight gain on bermudagrass pastures: no shade, 1.47 lbs.; artificial shade, 1.81 lbs.; tree shade, 2.34 lbs. This is because trees not only intercept sunlight, but actively cool the air through transpiration of moisture, acting somewhat like a swamp cooler.
An often overlooked factor to consider is heat stress and pregnancy. A trial through the University of Missouri found that cows with access to (artificial) shade had a pregnancy rate of 87.5%, compared to just 50% for cows without access to shade. I don’t think I need to tell you that a difference like that will have a huge impact on the bottom line.
The cost of establishing a tree and getting shade from it will be a bit variable. Are we talking about a fast-growing and cheap black locust seedling, or a slower-growing oak? A hybrid poplar you can propagate for free through cuttings, or a grafted honey locust?
For the sake of this article, let’s assume your primary aim is fast shade, and you plant nice-sized (two- to three-foot) black locust seedlings for $2 apiece. We’ll assume you’re buying enough Plantra tree shelters to get a quantity discount of $10/piece, and that you’ll get two uses out of each shelter (removing and reusing each after three years). That gives a cost per use of $5.
Next we’ll say it costs you $5 in labor to plant each tree, install the tube, and mulch around it. Altogether, we get a grand total of $12 per tree. For the sake of this comparison, we’ll assume there’s no cost share, although cost share through NRCS or a non-profit group could bring the cost down to $0.
How does that compare with a 1,200 square foot portable structure that could provide shade for roughly 50 stockers at 24 square feet per head? How many trees would we need to give the same amount of shade?
That’s obviously a moving target, as trees will provide virtually no shade for the first year or two, and produce tons of shade at age 80. I have a stand of three-year-old black locusts in my nursery with canopies averaging about six feet in diameter. That will provide 28 square feet or shade, or enough for one head. Now that they are established and growing well, we could have an average diameter of 12 feet in another three years, giving us 113 square feet of shade, enough for almost five head. Let’s say four head to be conservative.
So, if by year six you wanted enough shade in each paddock for all of your stockers to have access to shade, you’d need about 13 trees per paddock. If you have 40 paddocks, you’d need at least 520 trees. You’d likely want more trees to further distribute your shade, but this is a useful starting point.
At $12 apiece, planting cost would be $6,240. Again, cost share is available for tree planting in some states, meaning that number could be zero.
You can do your own research into the costs of mobile shelters. I have yet to see a mobile shelter that provides fodder, fixes nitrogen or feeds pollinators.
That doesn’t mean there’s no use for mobile shelters. They are a great tool to use while trees are getting established, or on leased ground where you can’t convince the landowner to plant trees.
So do your animals a favor: both buy that shademobile and plant trees. Once the trees are providing all the shade you need, you can sell the portable shade.
While this article cannot give numbers that will apply perfectly to your situation, I hope it’s at least given you some rough numbers to use as you determine how to go forward with silvopasture.
Austin Unruh is the founder of Pennsylvania-based Trees For Graziers, a company that helps farmers establish trees on their farms. He is also the author of The Grazier’s Guide to Trees, a starting point for farmers looking to add trees to their pastures. Learn more at TreesForGraziers.com.
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