lasi – wooly

carpa – fruit

Native range: W. North America

Leaves:

• needles (linear)
• flat
• radially spreading, turn up on twig
• most needles under 1.5” and tightly spaced on twig
• grayish or blueish green
• mostly straight
• young twigs greenish
• stomatal bands on both sides – 1 on upper (3–6 rows at midrib), 2 lower
• circular scar on twig when leaves fall

Cones:

• female cones:
  • woody
  • upright
  • deciduous
  • purple
  • 2–4” long
  • takes two years (growing seasons) to develop
  • disintegrate on tree, leaving only central core
  • rare; spreading occurs primarily through layering
  • scale densely hairy

Bark:

• gray
• smooth or ridged
• young trees – numerous resign vesicles
• older trees – scales and shallow fissures

Other characteristics:

• evergreen
• <100’ tall, 2’ diameter
• ‘spire-like’ crown (very tall and thin)

Ecology & Adaptations:

• most widespread fir in North America
• at subalpine elevations (and stunted tree at highest elevations) but also near sea level in cold-air drainages of major rivers (crowned by ice fields) that cut through Coast Range in SE Alaska/North Coast B.C.
• west of Cascade Mountains, mostly found between 4,000 and 6,500 ft. (1,200–2,000 m.)
• most abundant near timberline
• at tree-line, commonly in krumholtz form (i.e., crooked, twisted as a result of exposure to fierce freezing winds)
• in Cascades on eat and west slopes, and in eastern Olympic Mountains on dry sites
• shade tolerance:
  • lower branches remain intact despite shading by higher branches
  • crown shape responds to light conditions, e.g., may become umbrella shaped, with shorter branches in lower light conditions created by neighboring trees
  • shade-adapted leaves are relatively thinner so that available sunlight (usually flecks) can reach the photosynthesizing chloroplasts
  • sun-adapted leaves have smaller but more stomata per area, which permits regulation of water and gas exchange
• vegetative reproduction – at highest elevations, spreading occurs primarily through layering (i.e., branches rooting when they touch ground), which creates an “apron” at the base of some trees
• snow-adapted – layering is adaptation to heavy snow, wind, and cold temperatures that restrict growth much above surface of the ground
• sexual reproduction:
  • cones are rare
  • heavy winter snowfall shortens growing season and lowers soil temps to the point at which seedling establishment is difficult
  • individual trees reflect solar radiation, which creates a microclimate that is slightly warmer and where seedlings may establish
  • this microclimate results in clumping of trees
  • seeds overwinter under or in snow
  • cold, moist stratification is required for germination, but seeds remain viable for only a year
• seed dispersal: seeds have “wings” to facilitate dispersal by wind, so may colonize burned sites (especially mineral soils) but are otherwise sensitive to fire