Elyn Humphreys looks forward to climbing a 45-metre tower above the tree canopy
of a mature second-growth Douglas fir forest near Campbell River, B.C.
There she carefully analyses the measurements of a three-dimensional sonic
anemometer, infrared gas analyser and other meteorological instruments. No,
she doesn’t have her head in the clouds and this is no ivory tower.
Humphreys, who graduates this month with a master’s degree in Agricultural
Sciences, is making important discoveries about the role forest ecosystems play
in the global water and carbon balances.
“It’s the first time that the forest-atmosphere exchange of important greenhouse
gases such as carbon dioxide and water vapour has been measured year-round and
modeled for a temperate rainforest,” she says.
“We are learning that our highly productive West Coast forests which thrive
in long growing seasons and mild wet winters have important implications for
global climate models,” she adds.
As a member of UBC’s Biometeorology and Soil Physics Group, Humphreys is trying
to understand the limiting factors and driving forces behind water vapour fluxes
above and within temperate forests in order to determine the impact of climate
change on forest growth and water use.
Recent El Niño and La Niña events have shown just how variable
weather around the world can be from one year to the next. In response, the
seasonal and annual carbon uptake and water use by forests can vary dramatically.
The research team is studying the effects of soil, plant and atmospheric factors
on photosynthesis and respiration of forests, which also include mature aspen,
jack pine and black spruce forests in northern Saskatchewan.
Humphreys grew up in her native Sault Ste. Marie, Ont., with a love of botany
and math. She combined these at the University of Guelph where she earned a
Bachelor of Science in plant biology in 1997. Her supervisor at a summer job
had studied with Andy Black, a professor of Soil Science at UBC. Intrigued by
his work she contacted the university and packed her bags.
“She has become a key member of our research team,” says Black, whose work
is focused on measuring the amount of carbon dioxide being consumed by Canadian
forests.
“These measurements are essential to determine how much of the carbon dioxide
released by the burning of fossil fuels is taken up by our forests,” he adds.
“In fact, we know that only about half of the carbon dioxide released by human
activities remains in the atmosphere while the fate of the remainder is still
essentially unknown.”
The UBC carbon dioxide and water vapour monitoring sites are part of an international
network of approximately 80 sites called FluxNet, which aims to answer these
questions.
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