Common Name: California Nutmeg

General Information

Torreya californica is an evergreen tree with a conical crown when young becoming round-topped with age; it can grow 5 - 20 metres tall, occasionally to 25 metres. The straight, cylindrical bole is usually 20 - 90cm in diameter, occasionally to 120cm[, , ].
The tree is little used at present due to its scarcity (especially of large specimens), but it can be used to supply food, medicines and materials. It is sometimes grown as an ornamental, though the disagreeable odour of the needles detracts from its desirability[].
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 over the past 150 years. The plant is classified as 'Vulnerable' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

, ,

Range

South-western N. America - California

Habitat

Rare and local along mountain streams, protected slopes, creek bottoms, and moist canyons of the Coastal Range and Sierra Nevada; at elevations from sea level to 2,000 metres[].

Properties

Conservation Status	Vulnerable
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	15.00 m
Pollinators	Wind
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Torreya californica is a fairly cold-hardy tree, able to tolerate temperatures falling to between -17.7°c and -12.2°[]. One report says that trees are only hardy in the milder parts of Britain[], whilst another says that trees are hardy in Britain at least as far north as Edinburgh[]. This species is the only member of the genus that is fully adapted to cool maritime climates. It can actually grow faster in such a position than it does in its native habitat[].
Succeeds in ordinary garden soil, tolerating some lime[]. Undemanding as to the soil pH[]. Dislikes wind exposure[]. Requires a sheltered position and either high humidity or a moist riverside soil[]. Tolerates woodland shade very well[].
Species in this genus are generally adapted to growing in primary woodland. The seedlings are very shade tolerant, establishing well in the deeper shade of a woodland and then growing up to the light. They can sometimes be found growing in secondary vegetation, but they do not usually persist, being outcompeted by other, more light-tolerant species[].
The tree produces new sprouts from the roots, bole, and root crown following damage to above-ground portions of the tree. Numerous sprouts are produced at the base of the parent tree, although only one sprout usually survives after several years of growth[].
Usually slow growing, though trees can occasionally increase by up to 60cm in a year[].
The bruised leaves release a powerful resinous smell[]. The fruits are also aromatic[].
The seed takes two summers to mature[]. Trees often crop well at Kew Gardens in the UK (hardiness zone 7 - 8), but there were no seeds formed in 1994[]. A tree in fairly deep shade at Kew was carrying a good crop of seeds in the summer of 1996[].
Plants are usually dioecious, but isolated female plants have been known to bear fruit in the absence of a pollinating male[]. Plants are sometimes monoecious with dioecious branches. Male and female plants must usually be grown if seed is required.

Torreya californica is a scattered understorey tree 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 1,200 m a.s.l. Its altitudinal range is from near sea level (but usually above 200 m) in the Coast Ranges to 2,500 m a.s.l. 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[].

Edible Uses

Seed - raw or cooked[]. Said to taste somewhat like peanuts[]. The seeds are roasted and eaten[]. They are rich in oil[, ]. The ovoid seed is up to 3cm long[, ].

An edible oil is obtained from the seed[, ]. The seed oil has potential for use in cooking, being similar in quality to olive and pine-nut oils[].

Medicinal

The nuts have been chewed as a treatment for indigestion[]. A decoction of the nuts has been used in the treatment of tuberculosis[]. The crushed seeds have been rubbed on the temples in the treatment of headaches[]. They have also been rubbed on the body to cause sweating in the treatment of chills and fevers[].

Other Uses

The roots have been used as splints in basketry[].

The yellow-brown wood is smooth-textured, fine and straight grained. It is strong, elastic and highly durable; it works well, takes a good polish. A highly attractive wood of good quality, it has a a fragrance similar to that of sandalwood. Little if at all used at present due to low population levels, the wood was historically used for making cabinets, wooden turnware, novelty items, bows and for fenceposts[]. The wood is very durable - trunks of trees that were cut over 100 years ago have been found lying on the ground with little rot[, , , ].
The wood has been used for fuel[].

Propagation

Seed - best sown as soon as it is ripe in a cold frame. Some of the seed should germinate in the following spring though much of it might take another 12 months. Stored seed requires a period of cold stratification and can take 18 months or more to germinate. Prick out the seedlings into individual pots as soon as growth is observed and grow them on in light shade in the greenhouse for at least the next couple of winters, making sure to pot them on into larger pots as and when required. Plant them out into their permanent positions in early summer when the plants are at least 20cm tall.
Cuttings of half-ripe shoots in late summer[]. Cuttings do not grow well[].
Layering.