Krummholz

Krummholz or Krumholtz formation (German: krumm, "crooked, bent, twisted" and Holz, "wood") — also called Knieholz ("knee timber") — is a particular feature of subarctic and subalpine tree line landscapes. Continual exposure to fierce, freezing winds causes vegetation to become stunted and deformed. Under these conditions, trees can only survive where they are sheltered by rock formations or snow cover. As the lower portion of these trees continue to grow, the coverage becomes extremely dense near the ground.