Iowa Farmer Today
04-21-07
Tree barrier blocks odor drift, making expansion possible
By Jeff DeYoung, Iowa Farmer Today
WEST BRANCH -- A few years ago, Dale Vincent heard the words most farmers want to hear from their children.
“Our son, Jason, wanted to come back to farm, and I knew the only way he could do that was by putting up a hog building,” he says.
But, Vincent, who farms near here in Cedar County, ran into opposition from one of his neighbors. He was planning to build a 2,400-head wean-to-finish facility and realized he had to resolve those concerns before construction could begin.
“I’m the only farmer in my section,” he says. “I needed to do something.”
Vincent was able to come to an agreement with his neighbor, and the first pigs went into the finisher in November 2005.
The centerpiece of that agreement, he says, is a tree line that not only limits visibility of his building, but also serves as an odor filter.
“Our neighbor could see the facility from his back door, and we wanted to make sure it was out of sight,” Vincent says. “We did some research and learned that the prevailing winds come from the southeast in the summer and send any odor right toward our neighbor.
“Anything we could do to change the air stream would be an added benefit.”
Vincent started with a line of austrees, a willow-like hybrid tree known for its rapid growth rate. Austrees can grow eight to 10 feet per year, with a mature height of up to 50 to 70 feet.
“They were two to three feet tall when we planted them last spring, and they were
10 to 12 ft. tall by the end of the year,” Vincent says.
Not only are the trees making the site more aesthetically pleasing, but they have been effective in limiting odor.
“We did not get one complaint last year, and we’re really anxious to see how effective they are once they get taller,” Vincent says.

Trees can play a role in any odor management plan, says John Tyndall, a natural resources research scientist at Iowa State University in Ames.
Tyndall says if the trees are in the right place, they can be beneficial
“They need to be put in a place where they will maximize the filtration of particles in the air without disturbing the building’s ventilation,” he says. “They can’t be the sole method of odor control, but planting trees is one of many things that can be done to limit odor.”
Tyndall says assessing the effectiveness of trees and odor control is difficult. He says ISU has several field projects in the works, looking at how the trees will work in different locations.
“Data we have found shows trees can reduce movement of particulate anywhere from 10 to 30 percent,” he says. “You are increasing turbulence, so you are getting better vertical mixing.”
Tyndall says when a producer calls to ask for help, he will help them develop a strategy based on their goals.
“Are you primarily concerned about visibility, or is filtering odor your major concern? These are things you need to ask yourself,” he says. “A lot of it depends on how your buildings are situated. You don’t want to plant the trees too close to the buildings, because that affects both natural and mechanical ventilation.”
Many varieties of trees work well in any system, he says. Austrees are popular because of their rapid growth, Tyndall says, but other indigenous species can work just as well.
“I always think it’s good to mix species, because if disease comes in, you can minimize the effect of the pathogen,” he says. “Whatever you do, trees need to be properly managed, and that will take a certain amount of time and ex pense.”
Vincent also has a row of smaller trees, as well as some shrubs planted by the building. He also was able to obtain some cost-sharing funds to help pay for the project.
“We make sure we take very good care of our sites, and people have commented on how nice it looks,” Vincent says.
“We have to make sure that as hog producers we are doing everything we can to keep our neighbors happy, and to make sure people see that we care about our neighborhood and the environment. These trees not only get the buildings out of

sight, but they also are reducing the odor. So far, so good, and we’re anxious to see how well it works once everything has grown some more.”