grandis – Latin for ‘grand’ or ‘great’, as named by botanist David Douglas in the early 1800s because of its height and diameter

Native range: W. North America

Leaves:

• needles flat
• 3/4–1” long (~up to 2”)
• shiny
• tips are blunt to notched
• needles are of different lengths
• needles on branches are two-ranked and slightly pointed downward
• two white stomatal bands on underside of leaf
• spread so horizontally that top and bottom of twig usually visible (like scalp through parted hair)
• pungent balsam or tangerine aroma emitted by crushed leaves
• retained on tree for 7 years on average

Cones:

• female cones:
  • upright
  • deciduous
  • 3–4” tall
  • high in the crown where they fall apart through autumn
  • production begins at 20–50 years of age
  • winged seeds
• pollen and ovulate cones begin development during the summer and go through a period of winter dormancy before pollination, fertilization, and seed production the 2nd spring and summer

Bark:

• grayish to light brown (older)
• smooth to shallowly ridged
• layer beneath outer bark is reddish

Other characteristics:

• evergreen tree
• tall, straight, and thin (over 200 ft.)
• short branches on a very tall tree
• very regular branching pattern results from cruciform (arranged in a cross patter) buds
• in young trees, multiple branches emerge in a whorl each year from a single height (position) on trunk)
• twigs – opposite branching
• pubescent young twigs

Relevant info:

• fastest growing of all North American firs
• lifespan may reach 250–300 years

Ecology & Adaptations:

• native to Vancouver Island, British Columbia south to California on both sides of the Cascades
• scattered areas in the mountains east to Montana
• found in dry to moist coniferous forests, usually with Douglas-fir, river flats to fairly dry slopes, from sea level to mid-elevations in the mountains
• grows most successfully on streamside alluvium and deep, nutrient-rich valley bottoms
• mature grand fir forests are usually biologically diverse
• tolerates range of moisture:
  • well-developed tap root on dry sites reaches deep water tables
  • on moist sites shallow lateral roots prevail so that oxygen can more easily be absorbed
  • unlike seedlings, established trees are drought tolerant due to deep tap root, though moisture is limiting in its southernmost distribution
  • tolerant of fluctuating water tables and floods experienced in floodplains.
• pollinated by wind
• seed dispersal – winged seeds are wind-dispersed a few hundred feet from the parent
• fire:
  • resistant to low- and moderate-severity fires:
    • bark on mature trees that is 2 inches thick
    • germination of seeds is best on ash or mineral soil cleared by fire, except dry sites and those absorbing heat after blackened by fire
  • sensitive to fire:
    • relatively thin bark, low and dense branching habit, retention of leaves for years, and high surface-to-volume ratio of foliage
• shade tolerance:
  • moderate
  • seedlings continue to establish until canopy closes
  • large leaf area to capture light
  • low light-saturation point, so plant reaches maximum photosynthetic rate with relatively low light
  • two-ranked needle arrangement maximizes horizontal orientation of leaves
  • evergreen habit permits photosynthesis all year
• herbivory defense:
  • tree secretes pitch (oleoresin) to seal wounds created by insect attack
    • this terpenoid-containing substance (oleoresin) is toxic to both larvae of invading insects and their pathogenic fungal symbionts