Reindeer: In 1823, when Professor Clement Clarke-Moore of New York State published his poem, "The Night Before Christmas" in The Troy Sentinel, he couldn't have chosen a more inappropriate animal to pull Santa's voluminous sleigh. The legend of Rudolph was born. Red-nosed from the cold air, he and his companions had to fly to keep their parcel deliveries on time.
But, as any Lapp worth his seal meat knows, reindeer can't be hurried. Adapted to a cold life, they overheat all too easily, panting and salivating after less than a kilometre at full gallop. In the mild British Christmas climate, a few streets at a fast trot would do them in.
Reindeer have special noses. Covered in hair, they stay warm and dry because their design ensures that the air they breathe is heated up, and the exhaled air cooled, conserving body heat and water vapour. However cold it becomes, they don't become even the slightest bit pink. Red, never.
If antlers are vital when the sleigh crosses that winter wonderland, Rudolph is out of a job. After the autumn mating season, male reindeer shed their antlers. But the females retain theirs. So, come Christmas Eve, your children's presents may be hauled by Ruth, Rosemary or Rachel - but not by Rudolph.
Mistletoe: Worshipped by the Druids, mistletoe has long been a part of the Christmas festivities. But for how much longer? It is a parasite with no roots of its own, and its fate now hangs on the future of old orchard apple trees.
In 1957, England had 26,000 hectares of dessert apple orchards. Now, barely 10,000 hectares remain. Not so in France. The French have retained many of their old orchards and their mistletoe flourishes. Napoleon gave it a helping hand by planting poplars along French roadsides, essentially to shade his soldiers from the midday sun. Perhaps it was also to supply the infantry with sprigs of mistletoe to give to their sweethearts at Christmas.
Robins: There are more than four million pairs of robins in this country, and the bird was ranked sixth in the British Trust for Ornithology's Garden Birdwatch survey this year.
Although they look chirpy on our Christmas cards, ironically robins are less likely to survive cold winters than many other birds because they depend so much on ground-living prey. But, because a pair frequently rears two or three broods each summer, numbers recover quickly. And robins are fiercely territorial, which does allow them to live at high densities, particularly in woods, where up to 66 pairs have been recorded in a square kilometre.
The much loved robin has been little molested over the centuries, with a couple of exceptions. In the mid-1800s they became an epicurean treat, and, in the 1890s, a millinery adornment: the wings - or even the whole bird - were used to decorate hats.
Fir: Thanks to Queen Victoria's consort, Prince Albert - who made the Christmas tree popular in Britain - around five million fir trees are sold here each year. Nearly three-quarters are Norway spruce, a tree that is not even native to these shores, though it is an abundant forest tree across northern Europe, from Scandinavia eastwards. Around one in 16 of the commercial trees planted in Britain are Norway spruce. But a plantation - where the trees are planted close together to spur their upward growth - is a pale reflection of a natural spruce forest. The trees of northern forests - an inspiration for composers such as Jean Sibelius - grow up to 180ft and are accompanied by pines, birches and aspen and a plethora of mosses, flowers and lichens. Our plantations of quick growers (a Norway can be cut for Christmas in seven years) are so dense that few other plants survive on the ground beneath.Reuse content