Data collected over 20 years in New Hampshire links healthier white pine forests to falling ozone levels, say researchers; tighter federal, state restrictions are reducing ozone-producing chemicals that hinder ability of trees to photosynthesize
DURHAM, New Hampshire
February 26, 2014
– For more than two decades, an army of student scientists from kindergarten through high school have prowled New England's forests to collect data that University of New Hampshire researchers say link a healthier white pine forest to falling ozone levels.
The research is important: White pine is a powerful economic resource in the timberlands of New Hampshire and elsewhere, as well as providing environmental benefits such as wildlife habitat, carbon dioxide absorption and erosion control.
Ozone reduces the tree's ability to process sunlight into energy and ultimately food. As the federal government and states have put tighter restrictions on ozone-producing chemicals, levels have fallen and forests are feeling the benefit, UNH Professor Barrett Rock said Wednesday. Data compiled by the state's Department of Environmental Services-Air Resources Division show that since 1999, fewer areas in New Hampshire exceed the federal air quality standards for ozone, an indication that ozone levels are falling.
Rock said his researchers studied other factors like rainfall, temperature and insects to see if any of those could explain the data that showed healthier white pines: None of the factors were present.
Since 1991, UNH's Forest Watch program has sent students into the woods around the same time each year to measure the same trees and collect needles that give scientists a good idea of the tree's ability to grow and stay healthy.
Using scientific instruments and mathematical formulas, the students also calculate height, diameter, canopy cover and ground cover. They collect branches, seal them in plastic bags and put them on ice to transport them back to school, where they examine the needles to gauge how long the trees are keeping them and look for discoloration or decay that indicates poor health.
The combined body of evidence shows the trees are better off now than when the program started, Rock said. The results of the study were released earlier this month.
Not only does the student program provide researchers a pool of data to work with, the students learn hands-on science, many of them returning to the university to study with Rock. Since its inception, more than 350 schools have participated in Forest Watch around New England.
"I've had 20 or 30 students myself come to UNH because of Forest Watch," he said. "Some have gone on to get advanced degrees and some are teaching at colleges across the country."
And, Rock said, trees offer more than just economic and environmental benefits.
"There's an emotional benefit," he said. "You feel good walking in the woods and smelling that piney smell. There's something deep in our heritage linked to the woods."
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