Abies magnifica, first in described in 1863 by Andrew Dickson Murray (1812–1878), is commonly known as California Red fir, Silvertip fir or Shasta Red fir. There is a broad zone of hybridization between A. magnifica and A. procera that includes the southern Cascades, the Klamath Mountains, and associated coastal ranges of southwestern Oregon and coastal California. Trees in this zone display characters intermediate between the two species; the most conspicuous such character is a transition from exserted bracts (procera) to included bracts (magnifica) in the mature seed cones. These intermediate trees had been previously described as A. magnifica var. shastensis Lemmon (1890), a name which is widely used, but are now more appropriately called Abies x shastensis Lemmon (1897).
There are two recognized varieties:
- A. magnifica var. magnifica, the typical species which is described here.
- A. magnifica var. critchfieldii Lanner (2010), native to the southern Sierra Nevada. Described at this link.
Description. California Red fir is an evergreen coniferous species of tree which will grow up to 130 to 200 feet (40 – 60 m) tall with a 6.6 foot (2 m) trunk diameter at breast height, rarely to 250 feet (76.5 m) tall and 10 feet (3 m) diameter, with a narrow conic crown. The bark on young trees is smooth, grey, and with resin blisters, becoming orange-red, rough and fissured on old trees. The leaves are needle-like, 0.8 to 1.4 inches (2 – 3.5 cm) long, glaucous blue-green above and below with strong stomatal bands, and an acute tip. They are arranged spirally on the shoot, but twisted slightly s-shaped to be upcurved above the shoot. The seed cones are erect, 3.6 to 8.4 inches (9 – 21 cm) long, yellow-green (occasionally purple), ripening brown and disintegrating to release the winged seeds in fall.
Distribution. This species is native to USA — Oregon, California and Nevada at elevations of 4,500 to 8,600 feet (1,400 – 2,700 m) above sea level in mixed conifer forests. The zone of hybridization extends north from about Mount Lassen in California, and the boundary is somewhat more northerly on the east (dry) side of the species’ range, than on the coastal side.