I’m not into the whole Christmas tree thing, personally. People use massive swathes of land to grow pines and firs for only 5-8 years on average, for the sole purpose to be cut down. They all could have grown into beautiful, tall trees, but no.1
Once you bring the Christmas tree home, you spend countless hours trying to make it not fall down in the first hour after mounting, put gaudy, sparkly stuff on it, and then watch it decay for the next few weeks. Then in early January comes the fun dismantling part, when you need to throw the dessicated tree out without covering everything in needles. Of course, that inevitably fails, because chopping up a tree in your living room is hard work. So, even two months later there are still needles. Everywhere.
But some people are really into this kind of activity, so it’s understandable that we would try to make it better – with science. For example, try making the Christmas tree stay green longer. Could you put something in the water, or perhaps apply something to the tree itself?
This is the question that a bunch of year 7 schoolgirls in Sydney recently addressed together with plant ecologists from University of New South Wales. They took branches from Monterey pine (Pinus radiata), which is a commonly grown species for Christmas purposes in Australia.
Using five groups with 10 branches each, the girls subjected these “mini-trees” to different experimental conditions, such as keeping them in containers with beer or tap water, or spraying with hairspray. The health of the branches wasn’t just assessed visually – the students used an instrument that uses pulse light to determine how efficiently the pine needles are undergoing photosynthesis.
Unsurprisingly, the pines did not like drinking beer instead of water, and neither were they happy with energy drink. However, the idea to douse the branches with hairspray yielded a surprising result – the plants were healthier and stayed green longer than the control subjects.
One of the professors involved with the experiment speculated that this might be either because the hairspray helps the needles retain moisture better, or it might stop the branches sensing chemicals from decaying parts of the pine that would trigger more decay.
The students had a great time with this project, and they will be writing up their findings into a scientific paper. The experiment was done as part of the Scientists in Schools Program run by CSIRO.
So, now that the Christmas tree time is coming up, when you haul home the pine, make sure to invest in a can of hairspray, too. The tree will die eventually, but it might take a bit longer.