In August Leonard and I climbed Mount Lassen. The higher we climbed the more stunted and deformed the whitebark pines (Pinus albicaulis) along the trail became. I was enchanted by the shape of these conifers and the tenacity with which they clung to life.
A timberline tree, whitebark pines grow tall with a single main axis in protected situations. However, in exposed situations these pines form broad mats hugging the rocky ridges or are dwarfish with twisted and contorted trunks. Stunted, deformed vegetation found in subarctic areas or near the subalpine tree line is known as “krummholz”. The term means “crooked wood” and comes from the German words “krumm”/twisted, bent, crooked and “holz”/wood.
Coniferous species are most usually associated with krummholz. The word also can apply to trees found along beaches where deformation is also caused by persistent, fierce winds.
Intense winds and ice buildup kill apical (growing) buds, causing trees to grow more horizontally and die on the exposed side. When roots and foliage die on one side of the tree, spiral growth occurs. This twisted trunk is better able to distribute water when one side of the tree is damaged and protect the tree from desiccation.
More information about whitebark pines may be found in a previous post (10-27-17 Whitebark Pine).
The whitebark pines near Lassen Peak and elsewhere may struggle for survival in their harsh environment, yet their krummholz growth patterns are picturesque and beautiful to behold.