Scientific name: Pseudotsuga macrocarpa (G.Vasey) H. Mayr 1889

Synonyms: Abies macrocarpa Vasey, Pseudotsuga californica Flous, Tsuga macrocarpa (Vasey) Lemmon

Common names: Bigcone Douglas-fir

Description

Tree to 30(-45) m tall, with trunk to 2(-2.3) m in diameter, the bark thick, dark gray with reddish brown highlight, with broad, flat-topped, interlacing ridges separated by deep furrows. Crown thin, very broadly conical, with widely spaced, widely spreading, long, thin branches in the lower crown and progressively shorter ones above. Twigs reddish brown, minutely hairy at first, inconspicuously ridged. Buds 7-8 mm long. Needles sticking out all around the twig but most densely to the sides, (2-)2.5-4.5 cm long, 1-1.5(-2) mm wide with a short point at the tip, dull bluish green above, the stomatal bands grayish green beneath. Pollen cones 15-25 mm long. Seed cones (9-)10-15(-20) cm long, 4-6(-7) cm across, yellowish green before maturity, ripening dark brown, the seed scales hard and rigid, the bracts straight. Seeds (9-)10-13 mm long, the wings 10-20 mm long.

Mountain ranges of southern California, from central Santa Barbara County, east to southwestern San Bernardino County, and south to central San Diego County. Scattered as single trees or small groves emerging above shrubby chaparral on dry but sheltered slopes, or mixed with pines and other conifers in the lower portion of the montane yellow pine forest; (200-)1,000-2,000(-2,400) m. The climate is warm temperate, with cool, moist winters and warm, dry summers (annual precipitation 500 mm to 1,500 mm), snow occurs only at the higher elevations.

Conservation Status

Red List Category & Criteria: Near Threatened

Based on comprehensive mapping of localities from herbarium data, the area of occupancy (AOO) can be estimated as 315 km² (below the maximum of 500 km² threshold for Endangered), and the population is certainly fragmented. But there is no evidence of decline, save for some reports on there being few larger trees in some localities after fires. Near Threatened is therefore the appropriate category, as it was at the first assessment, the population trend appears to be stable. Above 800 m (Transition Zone) this species is mainly mixed with Pinus jeffreyi, Pinus ponderosa, Pinus coulteri, and Abies concolor at the highest elevations. Common evergreen shrubs in these open pine forests are Ceanothus cordulatus and Arctostaphylos patula. At the lower elevations it occurs in the drier Canyon Live Oak forest type, with sclerophyllous oaks, e.g. Quercus kelloggii, Quercus chrysolepis and Quercus agrifolia. The range of this species is relatively small and confined to the Transverse and Peninsular Ranges of the State of California, USA. The long, hot summers make it susceptible to forest fires, which are by far the main threat to this no longer exploited species. It has limited resistance to fire, but as fire frequency has increased due to human causes, protection from forest fires has become a major concern. As yet there seems to be no marked decrease of total known area of occupancy (AOO) since surveys on the geographic relationships between this conifer and wildfires were first reported in 1980, probably thanks to fire fighting and preventive measures. The wood of this species is close grained, hard and heavy, but not durable. It would only be suitable for coarse lumber, but is not exploited due to scarcity of the resource and other, more ecological values. It is perfectly suitable for amenity planting and as a specimen tree in gardens and parks in milder climates, but rarely seen outside specialist collections in arboreta and botanic gardens. It grows to a well-shaped, medium sized tree with attractive, large, pendulous seed cones and is worth being introduced and planted more often; obviously in regions with a suitable climate, such as southern Europe, or perhaps New Zealand and parts of Australia.

References

Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.
Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.
IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland