A lighthearted and seasonal Science Bit for you this month!
Ah, there’s nothing like a real Christmas tree. You can keep your plastic trees, sprayed white and gold or with fibre optic lights – for me, the annual trip to choose and collect our perfect pine tree symbolises Christmas itself and the beginning of festive few weeks of fun with friends and family.
But for some people in North America who also love the real thing, the humble Christmas tree is under threat from a very seasonal character that usually helps Santa rather than hinders him. Forests of Fraser firs in North Carolina are often frequented by deer who damage the Christmas tree crops by butting them with their antlers in order to mark their territory and by nibbling on the young shoots and buds. According to Christmas tree production specialist and agricultural researcher Jeff Owen from North Carolina State University, a single deer can munch a young Christmas tree down to the size of a pencil in no time at all.
Of course, a simple way to keep Rudolph out of the forests would be to erect good quality fencing, perhaps even electrified barriers, however with over 350 Christmas tree farms producing more than 20,000 acres of Christmas trees each year, fencing and fence maintenance is extremely expensive. An alternative is to use commercial deer repellents, but again, this can be prohibitively expensive, with 1lb of repellent costing around $18 USD, and up to 10lbs of product used per acre, two or three times a year.
Funded by the North Carolina Christmas Tree Association, Owen and his team have been researching effective deer repellents that would make a viable and cheaper alternative to the existing commercially-available products. Old wives’ tales recommend hair clippings, cayenne pepper and raw eggs to keep deer away, and it turns out that the latter of these isn’t far from the truth. The scientists discovered that a prepared mixture of dried blood and egg powder is the perfect deterrent for Bambi and friends, and can be bought very cheaply at a cost of just $2 per lb of product thanks to the fact that these are common, inedible by-products of the pet-food industry.
Owen says, “These products have an unappealing taste, but the decaying smell actually elicits a fear response in the deer and keeps them away from the crops”. It is hoped that dried blood and powdered egg could save threatened Christmas tree stocks in North Carolina, and with the team now making headway on extending their research to see if other pet food waste products, like liver powder and fishmeal, are as effective deer repellents, tree farmers all over the States could be spoilt for choice and assured of a sustainable future. Sorry Rudolph!