Nakai podocarp  (Podocarpus nakaii)

Classified as Endangered (EN) on the IUCN Red List (1).

Podocarpus nakaii is a medium-sized conifer with a relatively straight, slender trunk, a broad, rounded crown, and blade-like leaves, which are concentrated near the tips of the branches (2) (3) (4). The fibrous bark is greyish-brown in colour, peels off in narrow strips, and becomes ridged and furrowed with age (2) (3) (4), while the inner layer of bark is pale reddish-orange, becoming pale yellow when cut (4). The leaves of this species are long and leathery, measuring up to 11 centimetres long and 1.4 centimetres wide, and are spirally arranged around the twigs. Young leaves are reddish at first, later becoming bright green above and paler, silvery-green below (2) (3) (4).

Podocarpus nakaii is often confused with the more widespread oleander podocarp (Podocarpus neriifolius) and Buddhist pine (Podocarpus macrophyllus), but can be distinguished from both by its leaf buds, which are spherical in shape, and covered in tightly fitting, overlapping scales. Its mature leaves are also generally smaller than those of P. neriifolius, but wider than those of P. macrophyllus (2) (3).

Podocarpus nakaii is endemic to Taiwan, where it is restricted to a small area in the centre of the island, in Nantou County (1) (2) (3) (4).

This species occurs in broadleaved evergreen forest, at elevations of around 300 to 1,000 metres (1) (2) (3) (4).

Like all Podocarpus species, Podocarpus nakaii is dioecious, bearing male and female cones on the same tree (2). The male cones, which measure up to five centimetres in length, grow individually or in clusters of two to three at the bases of leaves, and are covered in small scales (2) (3). The female cone grows on a short stalk, and is highly modified, becoming swollen, fleshy and berry-like at the base. Measuring up to 1.2 centimetres long, the base is composed of two lobes, separated by grooves, and becomes red at maturity. Each cone bears a single, plump, unwinged seed (2) (3) (4). The female cones of Podocarpus nakaii usually ripen by April (4), maturing and falling within a single season (2).

Interestingly, Podocarpus nakaii has been shown to produce chemicals which mimic certain insect moulting hormones. These chemicals are believed to disrupt the growth and development of insects that ingest them (5) (6) (7), and may serve to protect the tree against insect attack (7).

Little information is available on the threats faced by Podocarpus nakaii. However, its populations are small and isolated, and are likely to be threatened by increasing human settlement, agriculture, and forest management activities (1).

There are no specific conservation measures currently known to be in place for Podocarpus nakaii. More information will be needed on this Endangered conifer and the threats it faces before appropriate conservation action can be taken to protect it.

To find out more about the conservation of Podocarpus nakaii and other conifer species, see:

• The Gymnosperm Database:
  http://www.conifers.org/
• Farjon, A. and Page, C.N. (1999) Conifers: Status Survey and Conservation Action Plan. IUCN/SSC Conifer Specialist Group, IUCN, Gland, Switzerland and Cambridge, UK. Available at:
  http://data.iucn.org/dbtw-wpd/edocs/1999-024.pdf
• Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland, Oregon.

For more information on wildlife in Taiwan see:

• Taiwan’s Ecological Conservation:
  http://www.gio.gov.tw/info/ecology/English/index_e.html