Pollution is making British Christmas trees bushier, and thus more desirable to the traditional customer, according to a study published in this week’s New Scientist.
The traditional layered tree, shaped like a wedding cake, is slowly giving way to one that is squat and bushy, owing to extra nitrogen in the air, the study, led by David Hanke of the University of Cambridge, found.
The additional nitrogen acts like fertiliser and promotes more branch growth.
Roger Hay, secretary of the British Christmas Tree Growers’ Association, said the British and the Americans prefer bushy trees that can be festooned with decorations, by contrast with the Germans, who like to have spaces between the branches.
Hanke led the research in which spruce trees were sprayed over three years with a range of chemicals, including acids and nitrogen and sulphur compounds.
”We found that nitrogen caused a big rise in levels of a hormone called cytokinin that causes Christmas trees to grow more branches,” he said, attributing the extra nitrogen to pig and poultry farms.
Hay said there are about 65-million Christmas trees currently growing in Britain. British growers sell about seven million trees a year, some of which are exported. An additional one million are imported. — Sapa-DPA