 | This article includes a list ofgeneral references, butit lacks sufficient correspondinginline citations. Please help toimprove this article byintroducing more precise citations.(January 2025) (Learn how and when to remove this message) |
Afir wave is a set of alternating bands offirtrees in sequential stages of development, observed inforests on exposedmountain slopes in several areas, including northeasternNorth America andJapan. Fir waves develop by wave-regeneration following winddisturbance, and is one of various types ofpatterned vegetation.
Fir waves form by theecological process of wave-regeneration. When a tree falls, agap in the canopy is formed. This exposes trees at theleeward edge of the gap to greater wind. These trees are thus more likely to die from damage and desiccation thanwindward trees. These leeward trees eventually die, gradually expanding the gap downwind. At the same time, young trees start to grow in the wind shadow in the windward portion of the gap, protected from the high winds by the surviving trees. The combination of dying trees at the leeward edge and regenerating trees at the windward edge results in the propagation of the fir waves in the direction of the predominant prevailing wind. The period of the waves is variable, typically about 60 years inbalsam fir (Abies balsamea). One can view these from the Appalachian Trail as it ascends the Hunt Spur ofMount Katahdin inMaine. "Looking out to the Owl" and "The Brothers" are extensive areas of this phenomenon.