The species of Christmas tree may vary from place to place, but for me the festive season is always associated with the aroma of the Pinus radiata (aka Monterey pine). It evokes memories that a plastic tree and pine Little Tree car freshener just can't match. Unfortunately, that olfactory experience comes at the cost of a floor covered in pine needles as the tree inevitably loses its grip on life. Now a group of Australian schoolgirls has discovered an easy way to prolong the life of the tree and keep the Christmas spirit lingering a little bit longer.

In an attempt to slow the inevitable browning of the tree and shedding of pine needles that accompanies many a Christmas, a year 7 science class from Kambala in Rose Bay, Sydney, examined different potential conditions. These included placing branches into containers of tap water, hot water, energy drink, beer, and in a container of water with the branch also sprayed with hairspray.

Their experiment saw 50 branches of Pinus radiata divided into five groups of 10 and observed for 27 days. Over this period, the photosynthetic health of the leaves was monitored using an instrument that applies a pulse of light to measure how efficiently the pine needles convert light energy into chemical energy.

"The beer and energy drinks turned out really badly," says Professor Angela Moles, an award-winning plant ecologist from the University of New South Wales (UNSW) who worked with the students on the experiment as part of the Scientists in Schools Program run by CSIRO. "The plants went brown very quickly and were not very festive at all. But the hair spray group were healthier than the control plants that were just kept in water. They even started sprouting fresh green needles."

While the experiments didn't go so far as to reveal why a dash of hairspray prolonged the life of the tree, Professor Moles theorizes the coating could prevent the plant from sensing chemicals from decaying branches that would trigger more decay, in the same way one rotten apple can turn a while bowl rotten.

"Or it may be that the hair spray simply blocks the pores in the leaves, keeping the moisture in," she says.

Whatever the reason, if you want your tree looking its greenest on Christmas Day and for a bit longer afterwards, then an investment in a can of hairspray could do the trick.