Three girls from the grade 7 class from Kambala High standing next to a Christmas tree

Still green, thanks to science. Pleased students from the grade 7 class from Kambala school with their Christmas tree.

Written by Professor Angela Moles

A Sydney high school experiment finds that hairspray may be the best way to keep your Christmas tree green.

Christmas can be exhausting, presents need to be wrapped, food prepared and cards written. Christmas trees can also find this period a little overwhelming.

They are cut from their roots, popped into a bucket and festooned with tinsel and baubles. It’s not uncommon for them to droop, go brown and drop needles.

An unusual solution

A year seven class from Kambala School in Rose Bay, Sydney, decided to find the best way to keep a cut pine tree looking fresh and festive throughout the season.

They tested popular pick-me-ups including energy drinks, beer and hot water. But what won out in the end was not a drink at all. The leaves stayed green after a generous coat of hairspray and being placed in ordinary tap water.

Scientists lend a hand

Professor Angela Moles and Dr Julia Cooke, plant ecologists from the University of New South Wales, helped the class design the experiment. Angela and Julia visit Kambala as part of a CSIRO initiative, Scientists in Schools.

Angela speculates the hairspray may work by preventing the plants from sensing chemicals from decaying branches that could trigger more decay – just as one rotten apple in a bowl turns the others rotten.

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

Putting pine to the test

The class of girls divided 50 pine branches into five groups of 10 and studied them for 27 days. The five experimental conditions were tap water, beer, energy drink, hot water, and tap water with hairspray on the leaves.

The branches that were covered with hairspray retained 90 per cent of their original needle health and after 27 days were actually growing new needles.

Kambala student, Isabella Spagnardi, aged 13, said the result surprised her. “It was a really interesting experiment because we could all have a go and try lots of different treatments. But I could never have pictured that hair spray would be good for keeping a Christmas tree alive.”

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