In such situations, rooted in narrow cracks or fissures, where there is scarcely a handful of soil, it is frequently over eight feet in diameter and not much more in height.

The tops of old trees are almost always dead, and large stubborn-looking limbs push out horizontally, most of them broken and dead at the end, but densely covered, and imbedded here and there with tufts or mounds of gray-green scalelike foliage.

Some trees are mere storm-beaten stumps about as broad as long, decorated with a few leafy sprays, reminding one of the crumbling towers of old castles scantily draped with ivy.

Its homes on bare, barren dome and ridge-top seem to have been chosen for safety against fire, for, on isolated mounds of sand and gravel free from grass and bushes on which fire could feed, it is often found growing tall and unscathed to a height of forty to sixty feet, with scarce a trace of the rocky angularity and broken limbs so characteristic a feature throughout the greater part of its range.

It never makes anything like a forest; seldom even a grove.
Usually it stands out separate and independent, clinging by slight joints to the rocks, living chiefly on snow and thin air and maintaining sound health on this diet for 2000 years or more.