Endemic to California, USA where historically it was heavily logged and today it forms small, localised subpopulations
Distribution
Torreya californica is endemic to California where it is mainly found in the Coast Ranges and the Cascade-Sierra Nevada foothills. In coastal areas it is distributed from southwest Trinity County south to Monterey County. In the Cascade-Sierra Nevada foothills, it is distributed from Shasta County south to Tulare County. Populations are usually small and localised.
Habitat and Ecology
It occurs as scattered understorey trees usually growing in moist and shady places in hilly to mountainous terrain dominated by tall conifers, especially Sequoia sempervirens, Picea sitchensis and Pseudotsuga menziesii. In the western valleys of the Sierra Nevada it is associated with angiosperms, mainly Acer spp., Cornus nuttallii, Platanus occidentalis, and Alnus rubra and here it strictly adheres to stream banks in steep canyons at altitudes around 1200m aboce sealevel. Its altitudinal range is from near sea level (but usually above 200m) in the Coast Ranges to 2500m above sealevel in the Sierra Nevada. On serpentine rock it becomes a stunted tree or shrub and occurs on north-facing slopes in coastal chaparral. It is capable of resprouting following disturbance such as fire although regrowth is slow.
Human Uses
In the past, Torreya californica was used for cabinet making, fencing and bridges, as it is rot resistant. Due to its current rarity it is no longer used. California Indians used it for their bows, seeds were roasted for food and some tribes (e.g. the Pomo) used the roots for basket weaving. T. californica is the most commonly cultivated species of its genus and can grow into an impressive, wide crowned tree with striking foliage and large, pendulous, plum-like green or glaucous seeds. It is almost exclusively used as an ornamental in large gardens or planted in arboreta. The name 'nutmeg' only refers to a superficial similarity with true nutmeg fruits (from Myristica fragrans, an angiosperm tree species).
Conservation Status
Global status and rationale
Vulnerable A2cd
Past logging has virtually eliminated Torreya californica from parts of its historic range and also removed most of the large trees across almost all of its range. Regrowth is reported to be very slow. On this basis a past decline of more than 50% of mature trees in the population has been inferred, leading to an assessment of Vulnerable under the A1 criterion.
Global threats
Logging in the late 19th and up to the mid 20th centuries virtually eliminated California torreya from the Vaca Mountains of Napa and Solano counties, and considerably reduced populations in the Santa Cruz Mountains and lower Russian River area of Sonoma County (Howard, 1992). Logging also eliminated many of the larger trees in the remainder of its range and resulted in a decline of mature trees in the total population, which is only now slowly being restored. As this species is dependent on forest cover, deforestation in parts of California has further contributed to a decline. This decline has now ceased or virtually ceased.
Conservation Actions
This species is know from several protected areas within its range.
References and further reading
Burke, J.G. (1975). Human use of the California nutmeg tree, Torreya californica, and of other members of the genus. Economic Botany 29:127-139.
Howard, J.L. (1992). Torreya californica. Available at: http://www.fs.fed.us/database/feis/plants/tree/torcal/all.html. (Accessed: 30 July 2010).
Murray, M. D. (1985). The California nutmeg. American Forests. 91: 40-51.
