Description:
This tree has a fairly extensive distribution throughout the Pacific Northwest, including the moist California coast and the middle elevations of many of the mountain ranges in the region. Much of the eastern part of its range, including eastern Oregon is a hybrid with the Rocky Mountain white fir (Abies concolor var. concolor).
They have one of the most symmetrical forms – the live ones often present themselves as Christmas trees in many towns.
Unlike most true firs the needles lie flat which will distinguish it from the white fir where the needles typically curve up from the stem. The 2”-4” cones stand upright from the branch. They can achieve a height of 250 feet (those grown nearer the coast) which is one of the taller firs in North America. They are more shade tolerant than many of its associated conifers.
Personal Observations:
I saw grand fir in the Mill Creek Wilderness Area, along with Douglas-fir, ponderosa pine, and western juniper. I did not see grand fir depicted in this area on any distribution maps so I added the area to my personal maps.
I also found grand fir in Shelvin Park just east of Bend, Oregon at an elevation of 3650, which is somewhat below its typical range. It was outside of all the boundaries of the distribution maps that I came across. This was probably due to both its proximity to the wetness of Tumalo Creek, and the canyon location that tends to hold cooler temperatures (under many meteorological conditions) than the surrounding vicinity.
I also spotted a few near the Strawberry trailhead on the start of my several day backpack into the Strawberry Mountain Wilderness area of eastern Oregon at 5700’ elevation.
Although its not anywhere near the High Desert or Great Basin, I remember finding my first grand fir near the town of Mendocino on the California coast. This is near its most southern extension. It was befriended by a large squadron of redwood and Douglas-fir trees. This vegetation association is quite different than the one found in the High Desert. There you would find ponderosa pine and western juniper. Douglas-fir is found in both areas; however the High Desert would likely contain the Rocky Mountain Douglas-fir variety (Pseudotsuga menziesii var glauca), and the California one would be the coast redwood variety (Pseudotsuga menziesii var menziesii).
It is probable that the variety of grand fir I saw in Oregon was the hybrid with Rocky Mountain white fir (Abies concolor var concolor).
Links:
https://www.conifers.org/pi/Abies_grandis.php