Not many people would say that it is the trees that make North American skiing great: after all, what skiers mostly enjoy is those parts of the mountain where the trees have been cleared to create wide-open snowfields. Perhaps mine is a lonely voice. But to me, what distinguishes skiing across the Atlantic from elsewhere in the northern hemisphere - and what makes it irresistible - is the forestry. In particular, the fact that trees commonly grow at altitudes of up to 11,000ft, right at the top of the ski areas where the best snow is usually to be found and at least 4,000ft higher than in most skiable parts of the Alps.
You might regard this as a viewpoint relevant only to highly skilled skiers. But what distinguishes good skiers is that they can safely go faster than the rest of us. By taking things slowly and carefully, average intermediates can get down all but the steepest of wooded slopes. And why should they do that? What's so great about skiing in the trees that you should forsake the great white moonscape of Val d'Isere and travel thousands of miles to North America? I have a variety of answers.
It was in Park City, Utah, that I learnt to love the trees. What distinguishes its ski area from many others created in former mining towns in North America is not so much its skiing, rather the brilliant idea of leaving around the slopes much of the industrial archaeology - winding towers, slag heaps, a spoil hopper - to rust away or otherwise return to nature: the effect is like skiing through history.
The east side of the area, where it adjoins Deer Valley, is a gem: quiet and out of the way, with a handful of snowbowls and a whole sweep of glades. After skiing the big McConkey Bowl two or three times, some new challenge was needed. So I went into the glades.
My tree-skiing technique is something of a cross between chess and a thrill sport. If you can't change direction quickly and in a small space, you have to stop frequently and think carefully. You don't rush. After all, if you are moving slowly you can hit a tree without damage to you, the tree or your self-esteem.
For most of the afternoon I skied the steep glades. And I realised that unless I left a trail of cotton thread, it was inconceivable that I could ever repeat a route through the trees. Despite my aversion to skiing the same run twice, I could happily have spent days in this small wooded area.
GET OFF THE CROWDED SLOPES
Steamboat in northern Colorado is probably the US resort most celebrated for its tree skiing. The ski area rises to 10,500ft in the Medicine Bow/Routt National Forest; and the slopes are covered with elegant aspens (which thrive on the area's western aspect), virile Englemann spruce and subalpine fir, and Lodgepole pines in dense stands at the higher elevations. Just to ride a chairlift through the trees is wonderful; to ski among them, especially in the areas up above 9,000ft, is even better.
I dropped off Steamboat's Storm Peak into the Closet glades. I saw only one other skier on a vertical descent of 1,547ft. Yet this was a busy day at Steamboat, and the pistes were crowded. At times the voices of on-piste skiers penetrated the forest, and towards the bottom of Closet I could occasionally see flashes of bright skiwear through trees. But in the glades there was calm and quiet.
Down at a crowded lift base immediately after lunch, you can lose touch with the joys of skiing. But trees provide a screen; and once you get into the forest the unpleasantness melts away. There's no need to scale great heights. Most US ski areas are on Forest Service land, so the care and protection of trees is a key item on ski resorts' agendas; even in the base areas you can disappear.
Take Winter Park in the Arapaho National Forest, the closest resort to Denver. Near the bottom of the lifts is an area dedicated to children, the Snoasis centre. It is surrounded by a large, gently inclined slopes which extend even into the woods. There, hidden from view, is a gladed run called Moose Wallow which follows a winding path through the trees. It is a delight even for adult skiers, provided they don't mind a bit of poling.
Imagine if the ski area of Val d'Isere, Espace Killy, were - like the old London Bridge - sold to the Americans and shipped across the Atlantic. After only a few generations, the area, which rises from 6,000ft up to almost 11,000ft, would no longer be bald on top: in place of its pure, white scalp there would be a healthy green growth of trees. Instead of the existing ski playground, where the whole slope you are about to ski is visible even before you have tightened up your bootstraps, there could be vertical descents of almost 5,000ft of tree skiing, each descent a journey of surprises. The effect could be a bit like Wozzley's Way at Telluride, a "trail" (in North American terminology) which combines all types of intermediate terrain. A supreme example of the art of the trail- cutter, it hairpins off a 12,000ft wooded peak, runs down a steep pitch onto a short, sharp mogul field, and then circumnavigates a bowl before plunging down to the lift base.
Telluride, too, is in Colorado. But the pleasure of skiing among the trees is not confined to the western parts of North America. While at high, western altitudes the forests are a blessing, in the low-lying hills of the east they are a given: there, the blessing is weather usually cold enough to create and maintain snow cover. Despite climate change, resorts on the east coast can still survive - some even without artificial snowmaking - at altitudes where skiing is already impossible in Europe.
What keeps trees to the fore on the east coast is the fact that the trails are much narrower than elsewhere in the skiing world. This is partly an accident of history: many east-coast ski areas go back a long way, some to the Thirties when trails really were no more than trails. Elsewhere they have grown wider, partly because it makes grooming easier (and, recently, with bigger and faster ski lifts, because more space has to be provided for skiers on the slopes). But on the east coast, where there's a multitude of small ski areas, such improvements are difficult to fund. So many trails remain narrow, and trees fill much of the skier's view for the length of the winding descents.
Next time you are on a mountain where high winds are blowing away the snow, consider this: in North America, trees often provide a windbreak, even on the peak. And the next time you are feeling your way in bad visibility to the lower slopes, consider this: in North America, trees would be helping you to navigate. There's a lot to be said for trees.
More information: Park City (001 435 649 8111; www.parkcitymountain.com). Steamboat (001 970 879 6111; www.steamboat.com). Winter Park (001 303 316 1564; www.skiwinterpark.com)