Local Christmas tree farms are providing a backyard laboratory for Dr. Howard Neufeld, an Appalachian State University biology professor who is interested in how a warming climate might affect the tree industry’s future. The information he hopes to glean is important because it can help tree farmers make decisions regarding future plantings and farm locations.
Lauren Wood, a graduate student in the Department of Biology, measures tree shoot length to gauge differences in growth patterns of Fraser firs at tree farms ranging from 2,200 to 4,200 feet in elevation. (Photo courtesy of Scott Cory)
Neufeld will work with the university’s tree ring experts to analyze discs taken from tree trunks to determine tree growth during the last decade at the different elevations.
“Trees growing in hotter and dryer locations have greater loss of water because of the higher temperatures and lower humidity. They also release more carbon dioxide that otherwise might be available for growth,” he said.
“Although, we have heard from the growers that their trees grow to marketable size sooner at the lower elevations, our preliminary measurements at least of diameter growth suggests that trees at lower elevation this year seem to be growing substantially less than those at the higher elevations, but maybe they grow less in diameter but faster in height,” Neufeld said. “We will measure that later in the study.”
Trees grown at higher elevations experience less stress related to water loss, Neufeld explained. “A lot of times the trees at the highest elevation farms (4,200 feet) are in clouds or fog 35-40 percent of the time and get 35-45 percent of their water from the fog. They also have lower evaporation rates,” he said. “If trees are hotter and dryer, they have to deal with greater loss of water because of the higher temperatures and lower humidity.”
Future climate warming could mean that growers at the lower elevations find themselves in an area that is no longer favorable for growing Fraser firs. Will they have to move their farms to a higher elevation as a result? Will the trees at the higher elevations, which also will experience warming, grow more or less?
A conifer chamber is used to a measure a Fraser fir’s photosynthesis, the process by which a tree makes sugars, and transpiration, which is the tree’s water loss. (Photo courtesy of Scott Cory)
“We don’t know the answers but those are some of the things to consider,” Neufeld said.
“Growers may ask themselves if they want to invest $100,000 by planting trees at 2,200 feet knowing that in 10 years they might not recoup their investment. We won’t be able to attribute differences to any one specific factor, but by looking at what the trees are doing at the lower elevation, we can say that if it gets warmer and the temperature becomes similar to what it is at the lower elevation farms, growers will know what to expect and perhaps adjust their management practices.”
Homepage caption: Scott Cory, a graduate student in the Department of Biology, adjusts a weather station used to monitor weather conditions at a Fraser fir tree farm. (Photo courtesy of Lauren Wood)
Republished with permission from Appalachian State University.