The most surreal part of Christmas is the migratory forest that pops up all around us for three weeks. It's a long forgotten middle European folk-rite that has become buried deep in our seasonal behaviour. Now, thousands of years later, we re-enact this midwinter over and over again in a thoroughly contemporary manner. Christmas trees now may well be entirely and unashamedly artificial objects: pink, fibre optic colour changing nylon. Real organic trees appear in the most surreal of locations: strapped to the cab of a crane high above the city, in arrays over the facades of department stores, in the sterile shiny lobbies of corporate institutions, and in the front rooms of homes sitting on carpets which if you think hard enough become the mossy floor of a forest (well, perhaps after a few sherries). It wouldn't be a bad basis for next years Dr Who Christmas special.

On a festivity-free fir tree theme, here are some photos of a pavilion from Montreal's 1967 Expo. That's the fair which more famously hosted Buckminster Fullers geodesic dome (as the US pavilion) and Moshe Safdies 'Habitat 67' (still going strong apparently as a housing complex).

This is the Canadian Pulp and Paper Pavilion. It was formed from 44 stylized tree tops, constructed with tongue and groove Douglas fir plywood panels over a steel frame and painted with various shades of green epoxy paints.

It looks great - like a giant sized Julian Opie. It's a building that appears to be a landscape which is always an exciting idea. But there is more to it - a narrative that informs the entire construction: The material it is made out of is what is depicted: So fir trees are both the object (the plywood formwork) and the subject (the thing that is being depicted).

Its abstraction - the geometric interpretation of 'forest' - suggests the relationship of abstract ideas and processes to the natural landscape. Thus individual tree trucks - with knots and grain that make each tree behave differently - become more generic material as they are processed to become sheets of plywood rolling off a production line (whose qualities such as structural performance becomes more consistent). In relation to its sponsors, the paper and pulp industries, the pavilion suggests a relationship to the Canadian landscape. This is the forest as natural resource for industry. In the same way, the Swedish landscape is reformed into the domestic generica of IKEA - a natural environment tamed, miniaturised and atomised into multiple locations. It's a landscape commodified.

Under the tree canopy, there is what looks like a Miesian pavilion. This housed four exhibits: A section describing forest legends across the world, the second section included two theatres formed by huge unwinding rolls of paper. The third section described the Pulp and Paper Industry's impact on the Canadian Economy.

The fourth, Lab 67 housed demonstrations of the chemical aspect of paper production, including its unlimited future uses. Visitors could also see French Canadian artisans creating paper by hand.

The pavilions tells a story that leads from dark, mysterious folk origins to flat smooth abstraction: from forests full of wolves, fear, and unresolved sexuality to the sterility of reams of paper stacked on the shelves of Staples. Between these two opposites is the history of human civilisation.

Perhaps Christmas trees are a ghostly return of the mysterious ancient forest, a rolling back of the mechanisms and constructs of civilisation that addresses the Big Bad Wolf or Little Red Riding Hood inside us all.