Main Page | See live article | Alphabetical index

Bigcone Douglas-fir

Pseudotsuga macrocarpa is the botanical name for the bigcone Douglas-fir.

It is a evergreen conifer from 50 to 100 feet (15-30 m) in height and 22 to 62 inches (56-155 cm) in diameter. Its growth form is straight and pyramidal. The deeply ridged bark is composed of thin, woodlike plates separating heavy layers of cork ; bark of trees over 40 inches (102 cm) in diameter is from 6 to 8 inches (36-64 cm) thick. Main branches are long and pendulous, spreading from 20 to 50 feet (6-15 m). Side branches are few. The needles, from 0.8 to 1.2 inches (2-3 cm) long, are shed about every 5 years. Female cones are from 4 to 7 inches (10-18 cm) long. Seeds are large and heavy, each having a short rounded wing. Roots are described as strong and spreading. The largest known bigcone Douglas-fir is 91 inches (231 cm) in diameter, 173 feet (53 m) tall, and is estimated to be from 600 to 700 years of age.

Bigcone Douglas-fir occurs in mountains of southern California. It is distributed from the Santa Ynez Mountains in eastern Santa Barbara County and the Tehachipi Mountains of southwestern Kern County south to Julian, San Diego County.

Bigcone Douglas-fir grows in a mediterranean climate, characterized by hot summers and wet, mild winters. Annual rainfall during a 30-year period on a bigcone Douglas-fir site in the San Gabriel Mountains averaged 30 inches (762 mm) and ranged from 10 to 49 inches (254-1,245 mm). Bigcone Doulgas-fir occurs between 2,000 and 8,000 feet (610 and 2,720 m). At low elevation, it occurs near streams in moist, shaded canyons and draws where aspects are mostly north and east. At elevations from 4,440 to 5,600 feet (1,350-1,700 m), aspects include south- and east-facing slopes. At these elevations, bigcone Douglas-fir also grows on sloping hillsides, ridges, and benches. At higher elevations, it occurs on south and west aspects on all types of terrain. The average angle of slope on which bigcone Douglas-fire grows is 34.5 degrees. Slope angles range from 2 to 90 degrees, although these extremes are uncommon.

The number of plant associates in bigcone Douglas-fir communities is usually small. Common overstory associates include bigleaf maple (Acer macrophyllum), California bay (Umbellularia californica), Digger pine (Pinus sabiniana), and white alder (Rhombus rhombifolia) . Shrub associates include bigpod ceanothus (Ceanothus megacarpus), red shank (Adenostoma sparsifolium), Eastwood manzanita (Arctostaphylous glandulosa), toyon (Heteromoles arbutifolia), white sage (Salvia apiana), black sage (Salvia mellifera), purple sage (Salvia leucophylla), and California scrub oak (Quercus dumosa). Ground cover is usually sparse and may include California buckwheat (Eriogonum fasciculatum), wild onion (Allium spp.), scarlet beardtongue (Penstemon ternatus), chainfern (Woodwardia fimbriata), and western brackenfern (Pteridium aquilinium var. pubescens).

There is no current commercial market for bigcone Douglas-fir wood due to limited distribution and access. It is heavy, hard, and fine grained but not durable. There is less sapwood than heartwood, and the latter contains pockets of resin. In the past, the wood was used locally for fuel and lumber. Bigcone Douglas-fir stands provide habitat for black-tailed deer, black bear, and various small animals. These trees provide preferred spring habitat for black bear in the San Bernardino Mountains. The seeds are eaten by various rodents and birds. Bigcone Douglas-fir is used for watershed restoration. The Los Angeles County Department of Forestry has extensively planted the tree over a 50-year period for that purpose. Some bigcone Douglas-fir - Douglas-fir (Pseudotsuga menziesii) hybrids show promise for outplanting on drier sites in the Douglas-fir region. These hybrids produce wood of comparable quality to that of Douglas-fir and have the drought tolerance of bigcone Douglas-fir.

Bigcone Douglas-fir populations are currently stable, with favorable rates of reproduction. The tree is being considered for more extensive plantings in semiarid locales. Its favorable qualities include resistance to drought, fire, insects, decay, and damage from ozone. The needles of older trees sometimes fade to yellow, drop, and trees appear dead only to sprout with renewed vigor within 2 years. The reason is unknown, although drought or insects may be possible causes.

US Forest Service Fire Effects Database: