Forest watchers from Sewell-Anderson Elementary School in Lynn, Massachusetts. Photo by Martha Carlson.
University of New Hampshire (UNH) professor Barry Rock has a piece of advice for anyone studying the forest: enlist a middle-schooler.
Rock directs Forest Watch, a program housed at UNH’s Institute for the Study of Earth, Oceans, and Space that invites teachers and their students from across New England to participate in long-term monitoring of the effect of air pollution on tree health. Specifically, students monitor ground-level ozone damage on the needles of eastern white pine, a species common on many school grounds.
“Teachers love this program because it’s hands-on, it’s real, and it’s relevant,” said Rock, the director of Forest Watch and a self-described “card-carrying, microscope-wielding botanist.”
Over the course of 20 years, thousands of students from more than 360 elementary, middle, and high schools in New Hampshire, Vermont, Maine, Massachusetts, and Connecticut have added information to the UNH data set.
Every year, students note whether the tree has retained its needles from previous years, in addition to updating basic measurements such as height and diameter. They also collect first-year needles from both the north and south side of each tree. There, using the naked eye, a handlens, or a microscope, they look for telltale signs of distress: areas of yellow mottling or tip blackening on the needles or, at the tissue scale, cloudiness and loss of cell shape. Samples of the needles they have analyzed are sent to UNH along with their findings, which are doublechecked in the lab using a spectrometer. According to Rock, middle-schoolers provide the most accurate information.
What they’ve found is that white pine needle health has improved dramatically over the past two decades, an improvement that mirrors the overall improvement in New England’s air quality. The data show a dramatic decline in ozone damage in 1996, 1997, and 1998, as the tightening of the Clean Air Act took hold, and a more gradual but continued decline since then.
This suggests that when smog levels drop, white pine health improves quickly. “These trees come back like you wouldn’t believe,” Rock said.
The program also connects students with space research. Their work is helping scientists understand images collected by NASA’s Earth-orbiting satellites. The digital images capture the range of wavelengths of light reflected by the varying kinds of vegetation, with each pixel representing an area of 30 meters square. Healthy white pine needles have more chlorophyll, and thus reflect a different wavelength pattern than unhealthy needles. By providing needle samples to UNH, classrooms are helping to confirm the satellite images and vice versa.
Phil Browne, a New Hampshire high school biology teacher who founded Forest Watch with Rock, had the idea that students could provide real help to scientists while learning about space technology after watching the shuttle Challenger explode soon after take-off on the morning of Jan. 28, 1986. All seven astronauts aboard were killed, including Christa McAuliffe, a teacher from Concord, New Hampshire, who had been chosen by NASA to give lessons from space.
“I was looking for a way of continuing Christa’s mission,” explained Browne, now retired, who taught at Concord High School himself for 22 years.
Since its beginning in 1991, Forest Watch has provided a model for a halfdozen other programs, regional, national and international, that connect scientists, students and satellite imagery.
In classroom teachers and students, scientists have “an army of researchers,” and the students benefit, too, Browne said. “Students felt that they were contributing to an understanding of how the world works and how forest ecology is monitored. It gives them a sense of hope.”