In fact, it seems one secret to their longevity is the harsh environment in which most bristlecone pines grow. One bristlecone pine near Wheeler Peak was dated to be more than 4,900 years old. Bristlecone pines in Great Basin National Park grow in isolated groves just below treeline.
Conditions are harsh, with cold temperatures, a short growing season, and high winds.
Bristlecone pines in these high-elevation environments grow very slowly, and in some years don't even add a ring of growth. This slow growth makes their wood very dense and resistant to insects, fungi, rot, and erosion. Vegetation is very sparse, limiting the role of fire. Bristlecone pine seeds are occassionally cached by birds at lower elevations. They do not achieve their legendary age or fascinating twisted shapes.