heteros – different (Greek)

phyllon – leaf (Greek)

Native range: Alaska to California

Leaves:

• linear
• flattened
• spirally arranged
• irregularly spaced
• varied sizes but short (up to 3/4”)
• short leaves are half the length of long leaves
• lower – 2 white bands of stomata (ill-defined) and indistinct green margin
• short petiole
• blunt apex
• attached to “pegs” on stems
• most needles drop off branch portions closer to trunk

Cones:

• pollen cones:
  • numerous
  • small
• seed cones:
  • numerous
  • small (2 cm long)
  • oblong
  • not stalked (sessile)
  • thin, smooth scales
• cones are produced in growing season, fertilization occurs and seeds develop and are shed in the second growing season
• seeds have large sings that facilitate dispersal by wind

Other characteristics:

• tree up to 200 ft.
• evergreen
• drooping leader
• horizontal or gracefully down-sweeping branches and delicate foliage

Relevant info:

• similar to T. canadensis, an east coast (North America) species
• cinnamon-red furrowed bark contains tannins used in tanning animal hides and in dyeing mountain goat wool and basket materials red in PNW Native American cultures
• Washington’s state tree

Ecology & Adaptations:

• Alaska to California, east to Montana, but much more common west of the Cascades
• found in moist, deep forests from sea level to mid-elevations in the mountains
• one of the most shade tolerant trees on the Pacific coast:
  • shade leaves are thinner than leaves exposed to full sun, which maximizes light-capturing area while minimizing investment in leaf tissue
  • relatively low light-saturated photosynthesis per unit leaf area in shady conditions
  • leaves deep in canopy can survive with 1% of full sunlight
  • shade tolerance enables species to self-replace in stands
  • on low branches, needles are concentrated near ends of branches
• tolerates low nutrient sites (though higher N results in more biomass production)
  • seeds can germinate on soils ranging from rotting wood to bare mineral soil as long as enough moisture is present
• tolerates low oxygen – adapted to wetter soils by developing shallow root system (that has easier access to oxygen in air), though shallow roots make trees susceptible to wind throw
• pollination by wind
• sexual reproduction:
  • cones are produced every year and especially abundant every 3 or 4 years
  • seeds remain viable for one growing season only
• seed dispersal – seeds have large wings that enable them to be distributed over long distances by wind
• herbivory:
  • Roosevelt elk and black-tailed deer browse branches
  • deer mice consume significant portions of seed fall
  • black bears, snowshoe hares and rabbits, and mountain beavers eat other parts of saplings and young trees
• herbivory protection – tannins in bark are defense against herbivory and insect infestation
• low fire resistance due to thin bark, shallow roots, highly flammable foliage, and a low-branching habit, with lichen covering branches
  • however frequency of fire is low due to their commonly occupied cool mesic habitats
• succession – shade tolerance makes this species a late-successional component but one that, in the absence of disturbance, can become the dominant, self-replacing canopy (since seedlings and saplings are shade tolerant)