Well, it’s almost that time again. You can almost see it, smell it, taste it—that perfectly cooked, magnificent bird! How on earth could it ever be a nuisance, and what do trees have to do with anything? After all, their time will come—next month.

Back up. Where did that bird come from? More than likely it came from a place just like the one shown in the photo. As you might imagine, these places generate a fair amount of ammonia, dust and airborne particulate matter. And therein lies the nuisance. According to an article in ScienceDaily, titled Trees Kill Odors And Other Emissions From Poultry Farms, these pollutants are a nuisance to humans living in the surrounding area. As suburban sprawl continues to encroach on rural areas, more people are being exposed to the nuisance.

These pollutants are potentially more than just a nuisance. They can pollute natural running water when they land in it and cause serious respiratory problems for people. But some researchers hypothesized that vegetation could filter much of the odor and particulate matter. They tested their idea, planting a variety of tree types, evergreen and deciduous, glabrous and not, short and tall, around poultry barns.

The ScienceDaily article notes: “In a six-year study, [researchers] found that a three-row plot of trees of various species and sizes reduced total dust by 56 percent, ammonia 53 percent, and odor 18 percent.” Their findings indicated it was most effective to plant either deciduous trees or trees with waxy coatings on leaves closest to the barn, with the other two rows of trees being evergreen. Researchers also point out the potential for energy conservation since these trees provide shade in the summer and a heat-loss barrier in the winter.

A concise and thorough discussion called Interactions Among Urban Trees, Air Pollution and Human Health, from Cornell University, can supplement your background knowledge regarding air pollution and trees.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

The National Science Education Standards Content Standard F states:

As a result of activities in grades 5-8, all students should develop understanding of

• Personal health
• Populations, resources, and environments

Life Science content standard C says:

As a result of their activities in grades 5-8, all students should develop understanding of

• Regulation and behavior
• Populations and ecosystems

Students can either research or be given information regarding how turkeys and chickens are raised commercially. They should be asked to identify the waste products generated and the impact of a commercial poultry operation on a community. They will encounter stories of the pollution associated with poultry farms, and the confrontations between the poultry farm owners and neighbors.

Then ask students to brainstorm ways to mitigate the pollution using natural, sustainable materials. You may need to drop a few strong hints to lead them to the idea of using vegetation. You can ask, “What if a row of trees was planted around the exterior of the poultry barn? What would that effect?” Students have some idea that trees exchange materials with the environment. “What kind of tree, deciduous or evergreen, would be best and why?”— assuming you live in an area of the country where trees do lose their leaves. Students will see benefits to both, and will perhaps lean to the evergreen. Then ask, “Well, if one row is good, would two or three be even better? What combination of tree types would you choose and why?”

Share the researchers’ findings with students. How do their ideas compare? What questions or ideas for additional research can students generate?

Here are additional related resources from the National Science Digital Library Middle School Portal: The Facts About Ammonia; The Nitrogen Cycle; Measuring Nitrates and Their Effects on Water; and Inside the Human Body: The Respiratory System.

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