Krummholz

thumb|Krummholz Pinus albicaulis in [[Wenatchee National Forest in north-central Washington, United States]] thumb|Wind-sculpted krummholz trees, Brian Booth State Park|Ona Beach, [[Oregon, United States]]

Krummholz (, "crooked, bent, twisted" and Holz, "wood") — also called knieholz ("knee timber") — is a type of stunted, deformed vegetation encountered in the subarctic and subalpine tree line landscapes, shaped by continual exposure to fierce, freezing winds. Under these conditions, trees can survive only where they are sheltered by rock formations or snow cover. As the lower portion of these trees continues to grow, the coverage becomes extremely dense near the ground. In Newfoundland and Labrador, the formation is known as tuckamore. Krummholz trees are also found on beaches, such as the Oregon coast, where trees can become much taller than their subalpine cousins.