UNH Project Reconstructs a Bit of 17th Century History

Forestry Students Busy Identifying Trees From Henry Hudson's 1609 Palisade

By Sharon Keeler
UNH News Bureau

April 26, 2001


DURHAM, N.H. -- A University of New Hampshire scientist and his students have undertaken a unique project to help reconstruct a bit of 17th century history.

Barrett Rock, UNH professor of forest resources, and students in his wood science and technology class are scrutinizing 50 samples of wood excavated last year in Albany, N.Y. The samples were taken from the site of a new parking lot for dating by Paul Krusic, a scientist from Columbia University's Lamont-Doherty Earth Observatory.

The wood came from remnants of old buildings, piers and the palisade originally built by Henry Hudson in 1609. Archaelogists working on the site have associated structures and artifacts with the fall beaching of Henry Hudson's ship the "Half Moon" while he was attempting to find the northwest passage to the Orient.

Rock, a scientist in UNH's Institute for the Study of Earth, Oceans, and Space, was contacted by Krusic to identify the pieces of wood, with the hopes of reconstructing a picture of what the forest looked like in 1609. Krusic was a UNH student 22 years ago,

"My job is to date when the trees were felled for construction of the settlement buildings and palisade, and to extract the record of climate recorded in the wood's annual ring widths," says Krusic, who is working with the archaelogical firm that uncovered the site. "The wood Barry's class is working with could give us some idea of what type of natural, climate variation is possible in New England. Due to the precise nature of tree-ring evidence, these dates can be resolved to the year, which is an archaelogist's dream."

Rock saw the project as a perfect opportunity to get his students involved. Working teaching assistant Ben Woodward in the lab, a dozen students this semester are putting theory into practice as they try to figure out the type of tree the wood is from, its age, and other factors about the climate conditions under which it grew.

"See, this sample has no resin canals, so on first look it could be hemlock or cedar," says Mike Gagnon of Bedford, holding up a piece of a tree that pre-dates Columbus' voyage to the New World.

They compare the cellular characteristics of their wood samples with photographs in books, and study razor-thin, cross sections under high-powered microscopes. Things like color, growth rings, evenness of grain, cell-wall thickness and "crossfield pitting" help them identify the samples as pine, spruce or cedar, as well as the tree's age. Crossfield pitting is one way the cells in a tree trunk "communicate with one another," says Rock. Each species of tree is characterized by a specific kind of crossfield pitting, thus aiding in the identification of each wood sample.

"Good science is detective work," says Rock. "Each pattern in the wood has a story to tell. A lot can be inferred from observation."

Rock, like Krusic, is especially interested in noting how the forest composition has changed over time.

"What species are no longer growing in the area today, and can this tell us things about climate and weather back in 1609?" he asks his students. "We know, for example, that climate change has caused species like northern white cedar to migrate north and spruce and balsam to move to higher elevations. If we can identify these species from the 1609 stockade this will help confirm that the forest composition in this area has changed with climate."

Growth rings also infer climate, and Rock explains to his class that they can reveal things like whether there were drought conditions during a specific year. Oxygen isotope levels in the wood's cellulose can be used to infer the average temperature down to the degree.

"There's a lot of history here," says Matt Webb of Hampton Bays, N.Y., as he fingers a 400-year-old sample of what he believes to be white pine. "I can't think of a better way to put what we've learned into practice. It's exciting to be part of something bigger than just this class. The ongoing study will help people better understand what it was like back then."

Kusic will use the data gathered at UNH to add to information collected from other sites of the same species. "Reconstructing past climates and how climate change affects human and plant distribution is big science now," he says. "As in the past, many civilizations have either failed or moved due to changing climate patterns. Understanding the dynamics of natural variability in the climate system by looking back into the past before CO2 fertilization, etc., is the first step in understanding to what degree we are mucking about with nature."


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