The immense pleasure of mountain biking here is in the combination of majesty, menace and effort. 'Majesty' captures well the dignity of nature and the awesome color tones. Maybe 'menace' is bit excessive. I don't go that fast. Let's try 'peril' or 'risk' . . . there is always the prospect of skidding on a wet root, or catching a wheel while hopping off a rock. 'Effort' is taken for granted in mountain biking, even for those who are bussed to the top of a mountain. The short pushes to get up rooted inclines have the heart pounding at an aerobic pace (for those for whom sport must have a health purpose). The strain on the neck, shoulders and forearms to keep control of the front wheel feels afterward like you have just finished three sets of military presses.
It doesn't get much better than this!