Colorado State Study Shows Home-Field Advantage for Leaf Decay

Colorado State University scientists have found that home-field advantage extends beyond the stadium and into science. The same "home vs. away" theory can be applied to where leaves decay. Scientists calculated the home-field advantage for leaf decay in forests around the world and found that leaves decay up to 30 percent faster at "home" than "away."

Leaves decay beneath tree species from which they derive, creating a home-field advantage, or leaves can be blown away and decay beneath different tree species, creating the "away" factor.

Why is that important?

Decomposition is important for scientists to study because the process transfers large amounts of carbon dioxide to the atmosphere, influencing the Earth’s climate.

"In sports, home-field advantage often occurs because players are more familiar with their home field – they know where the bumps and divots are and have the support of home town crowd ," said Ed Ayres, author of the study and researcher at Colorado State’s Natural Resource Ecology Laboratory. "Likewise, the home-field-advantage for leaf decay probably occurs because the soil organisms that break down leaves adapt to the type of leaf they encounter most often, which will normally come from the trees above them."     

The two primary factors that control decay rates are the climate and the nutrient content of the material being decayed, but other factors also contribute to the rate of decay. The CSU study concluded that on average leaf decay was 8 percent faster at home than away, indicating to scientists that home-field advantage should be added to the list of factors that control decay rates.

This was based on data compiled from forests in North America, South America, Europe and Hawaii, which included tropical, temperate and boreal forests. The largest home-field advantage was seen between sycamore maple and Douglas fir in Poland.

"Prior to this study, scientists knew that the home-field advantage could speed up leaf decay in some ecosystems, but they didn’t know how important it was or how many ecosystems it occurred in," Ayres said. "CSU’s study is the first to quantify the magnitude of home-field advantage for leaf decay and the first to show that it is widespread in forest ecosystems around the world.  

"We’re not saying that home-field advantage is the most important factor controlling decay, but we now know how important it is," said Ayres.

The study is published in the March 2009 issue of Soil Biology and Biochemistry and was written by 10 scientists in CSU’s Natural Resource Ecology Laboratory: Ed Ayres, Nate Mellor, John Moore, Bill Parton, Breana Simmons, Rod Simpson, Meg Steinweg, Heidi Steltzer, Matt Wallenstein and Diana Wall.