Pinus amamiana Koidz.

Pinaceae

Endemic to Japan where it was formerly exploited for its timber but more recently the population has been much reduced by pine wood nematodes accidentally introduced from the U.S.A.

Associated Names:

amami goyo and yakutane-goyo

Description

Taxonomic notes

The relationship of this species with the very similar species P. armandii, P. fenzeliana and P. morrisonicola and the infraspecific taxa in this group of East Asian pines belonging to subsection Strobus is in need of further investigation using DNA sequence data. Pinus amamiana may be most distinct in its cones and seeds, which seem to be more morphologically adapted to seed dispersal by birds and rodents, with small cones and relatively large, virtually wingless seeds. However, from DNA analysis of other pines with such cones (e.g. P. albicaulis and P. cembra) strong selective pressure has determined the evolution of these adaptations and they are not necessarily good indicators of phylogenetic relationships.

Distribution

Endemic to Japan on the southern island of Kyushu (Yaku-shima, Tanega-shima). In Yaku-shima there are three sub-populations; Seibu (western side of Yaku-shima) with 2000–3000 individuals, Hirauchi (southern side of Yaku-shima) with <1000 individuals, Takahira (south-eastern side of Yaku-shima) with <100 individuals. The extent of occurrence is estimated to be 600km², with an area of occupancy estimated at 50km². In Tanega-shima, the main one sub-population is located at the centre of the island. There are about 300 mature trees, and the number is decreasing due to pine wilt disease.

Habitat and Ecology

Pinus amamiana occurs in exposed, open stands in often sparsely vegetated localities on rocky slopes at between 50 and 900m above sea-level on two smaller islands in the south of Japan. In Yaku-shima, it occurs between 250-900m while on Tanega-shima it occurs between 50–200m.

Human Uses

No recent uses have been recorded of this species; in the past its timber was exploited and used locally for construction, carpentry and wooden canoes for fishermen. It is reported to be very rare in cultivation, but since it has frequently been referred to as P. armandii var. amamiana or even equated with that species (as it was considered by E. H. Wilson, 1916), there may be trees in collections (arboreta etc.) that are misidentified. It may be somewhat more common in Japanese gardens.

Conservation Status

Global status and rationale

Endangered A3ce; B1ab(iii,v)+2ab(iii,v)

Both under the A criterion and under the B criterion, this species meets the threshold for Endangered. Even though exploitation has ceased, the more recent infestation with pine nematodes continues to cause serious decline of the population.

Global threats

This rare species has an area of occupancy (AOO) of less than 100 km²; the total population size amounts to fewer than 3000 trees (ca. 2000 on Yakushima) and is declining. These trees were formerly exploited for timber and regeneration is slow due to exposed conditions. Pine wood nematodes accidentally introduced from the U.S.A. have caused increased mortality among seedlings and saplings according to information obtained by Tetsukazu Yahara of the Japanese Plant Specialist Group (IUCN-SSC) in 1999. Mature trees are reported to be affected in Tanegashima (Nakamura et al., 2001).

Conservation Actions

The sub-population on Yakushima occurs within a protected area. There has also been a survey of surviving trees in their natural habitats on the two islands and a distribution map was made to aid in-situ conservation. These activities are carried out with help of local NGOs, The Yaku-shima Yakutane-goyo Research Group and Tanega-shima Yakutane-goyo Research Group, Kagoshima Pref., the Yaku-shima Forest Office of the National Forest Agency and the Forestry and Forest Products Research Institute.