Higher CO2 makes pine trees more productive
Washington: A new research has found that pine trees grown for 12 years in air one-and-a-half times richer in carbon dioxide (CO2) than today’s levels produced twice as many seeds of at least as good a quality as those growing under normal conditions.
The findings suggest some woody tree species could, in the future, out-compete grasses and other herbaceous plants that scientists had previously found can also produce more seeds under high-CO2, but of inferior quality.
“Even if both groups were producing twice as many seeds, if the trees are producing high-quality seeds and the herbaceous species aren’t, then competitively you can get a shift,” said Danielle Way, a Duke post-doctoral researcher.
Way and her co-researchers collected, counted and analyzed seeds produced at the Duke Free Air CO2 Enrichment (FACE) site in Duke Forest, near the university’s campus.
There, growing parcels of loblolly pine trees have been receiving elevated amounts of CO2 around the clock since 1997 in a Department of Energy-funded project designed to simulate natural growing conditions.
Their analysis found the high-CO2 loblolly seeds were similar in nutrient content, germination and growth potential to seeds from trees growing under present-day CO2 concentrations.
“If anything, they actually seem to be slightly better seeds rather than more seeds of poorer quality,” Way said.
“The notion here is that if the trees are producing more high-quality seeds at high CO2 compared to grasses and herbs, then the trees may be at an advantage,” added study participant Robert Jackson.
The ultimate competitive outcome will depend on how other trees comparatively respond to high-CO2, according to James Clark, another Duke biology professor and Nicholas School professor of the environment who also participated in the study.
“We don’t know that yet, because we only have estimates for loblolly pines,” Clark said.