By SUSAN MYKRANTZ
Ohio Correspondent

WOOSTER, Ohio — Dr. David Nowak can readily recite a laundry list of reasons why trees have a value to society and the environment. Nowak, a researcher with the U.S. Forest Service, was the keynote speaker at the recent fifth annual “Why Trees Matter Forum” on the Wooster campus of the Ohio Agricultural Research and Development Center.

He explained trees play a vital role, both environmentally and in society, and   selecting a management strategy for the forest influences the benefits from the forest, such as noise reduction and wildlife habitat.

Trees are credited with producing much of our oxygen. In reality, Nowak said they only produce 67 million tons – a small fraction of what is actually used by the population – and most of the oxygen produced comes from the ocean. But trees can block about 96 percent of ultraviolet radiation.

“It is important to protect the susceptible members of the population, such as children and older adults,” he said. “But a canopy of trees is much more beneficial than an individual tree, which only blocks 50 to 60 percent of ultraviolet radiation.”
Trees can help with greenhouse gas reduction, too. Nowak said climate changes in temperature and precipitation are not going to be evenly distributed. “Some areas are going to be wetter and some areas are going to be drier,” he said.

“If we see shifts in the climate, it will change what trees we need to plant to adapt for the future. What is a natural choice in the past, may not be a natural choice in the future.”

If trees are planted around buildings, it can reduce energy use by providing shade in the summer and blocking wind in the winter. He added that cities store heat and tend to be 2-3 degrees warmer than rural areas.

“We see more pollution in areas where the temperature is warmer, and that increases power usage,” he said. “If we can reduce energy use, we can also reduce energy production. Cooler air temperatures are important in reducing air pollution.”

One misconception, according to Nowak, is that trees increase the property value of a residence. “Trees have no affect on the property value until it is sold,” he said.

At present, according to Nowak there is no real measurable data on the benefit of trees in improving water and air quality.

“We do know that we need clean water and clean air to maintain the human population,” he said. “Forty-seven percent of the population in the United States live in areas that do not meet the clean air standards for ozone levels. Leaf area and canopy cover are worth a lot. More leaves offer more benefits to encourage water and gas exchanges.”

Nowak said the U.S. Environmental Protection Agency is starting to regulate tiny particles of pollutants, which can be washed or blown off tree leaves onto the soil, becoming a soil contaminant.
Even though scientists don’t understand how our bodies react to seeing trees and other forms of vegetation, social, physiological and aesthetics are the primary reasons that trees matter, Nowak said.