When you stand by a big Sequoia and look up, the limbs look like normal trees in their own right, growing out of a cylindrical planet.
It is very hard to get a sense of scale with something so large that cannot be seen well from a distance. From afar the forest obscures any clear view of individual trees; up close the limbs get in the way.
By walking around a tree and taking its measure from several perspectives, you can accumulate a sense of the whole thing. A fine method for the imagination but lousy for photography.
Using a panoramic camera vertically solves the problem. This is a 35mm Widelux shot. As the camera lens pivots during exposure, it sweeps a slit across the cylindrical film surface, resulting in a 140 degree scope of view. Unlike a wide-angle lens, the panoramic camera does not diminish the size of the subject, but it does bend straight lines. In this view the distortions do not detract from the effect. The image proportions are 2.3 to 1.
Nowadays, ironically, one could use the cumulative effect of several pictures to construct a panorama (horizontal or vertical) using a computer. RealSpace, Quicktime VR, and VideoBrush are software applications that can stitch together several overlapping photographs taken from the same point of view. Theoretically, one could use Quicktime VR to combine photos taken from different perspectives, so the tree image could be "rotated" about an axis via the computer, but such an effect psychologically miniaturizes large objects.
I'll leave such cyber-bonsai to people who prefer to live virtually rather than actually. I like my trees to smell like trees, feel like trees, sound like trees, and to loom over me majestically like a big tree should.