Frigid High Elevation Uplands

Description

BpS Dominant and Indicator Species
Symbol Scientific Name Common Name
PIRU Picea rubens Red spruce
BEAL2 Betula alleghaniensis Yellow birch
ABFR Abies fraseri Fraser fir
ABBA Abies balsamea Balsam fir
FAGR Fagus grandifolia American beech
TSCA Tsuga canadensis Eastern hemlock
ACSA3 Acer saccharum Sugar maple
QURU Quercus rubra Northern red oak
Disturbance Description
This setting is characterized by stable, uneven aged forests with canopy dynamics driven primarily by single or multiple tree disturbances resulting in gap-phase regeneration. Natural disturbances include lightning fire, debris avalanches, wind events, and ice storms. Occasional extreme wind events disturb larger patches on the most exposed slopes.
Strong winds, extreme cold, rime ice, and other extreme weather are periodically important (NatureServe 2007).

Weather disturbances, including windthrow, insect attack (especially bark beetle, spruce budworm, fungi), and ice storms, occur at intervals of 100 to 200yrs and are the primary disturbances. Rare extreme weather events are also important large-scale disturbances. Insect outbreaks, including bark beetles, spruce budworm (20yr intervals), and butt rot (a fungi; predisposes stands 50-70yrs old to windthrow), are also important disturbances. These disturbances likely pre-dispose the forest to fire during drought conditions.

Fire Regime Group V. Surface fire is extremely rare, at greater than 1,000yr intervals, while replacement fire is more frequent, at 300 to 1,000yr intervals, and affects large patch sizes. As much as 25% of this biophysical setting may be considered a non-fire regime. In spruce-fir dominated parts of this setting, replacement fires are severe and kill most trees and understory, removing most if not all of the canopy and allowing pioneer species to emerge. Recent research indicates that on the most exposed sites, stand replacement fires in spruce-fir can result in a stable shrub-dominated community ("heath balds"). Mixed fires pass through the understory of the northern hardwood component, killing most of the smaller trees, leaving behind some large, well-established trees while creating canopy openings. Occurrence of fire is most frequent on sites where northern red oak dominates.

Lumbering and fire and/ or fire alone will scarify soils and pin cherry dominates badly burned areas. Yellow birch invades stands and becomes dominant later. Invasion by spruce – fir slow on badly burned sites.