Pinus thunbergii

Parlatore 1868

Common names

Japanese black pine (Richardson and Rundel 1998), KURO-MATSU, O-MATSU [Japanese] (Ohwi 1965).

Taxonomic notes

Syn: P. thunbergiana Franco; P. thunbergii Lamb., nom. illeg.; P. massoniana sensu Sieb. & Zucc., non Lamb. It belongs to the large subsection Pinus, within which it seems to be most closely related to P. hwangshanensis and P. nigra (Hsia 1936, Farjon 1984). Recent sequencing of its chloroplast genome (Wakasugi et al. 1994) provides hope that its phylogeny will soon be well understood, but current understanding suggests that along with P. densiflora and P. yunnanensis, it may have found a warm-temperate refugium in central Asia during the mid-Tertiary, providing a plausible linkage to western Asian populations of P. nigra (Millar 1998).

Description

Trees to 40 m tall, with trunk often divided in the wide, dense, dome-shaped or flattened crown. Bark dark gray or purple-gray, scaly, longitudinally fissured. Branches light brown with many bracts, thereafter becoming glabrous, often ridged. Young shoots covered with a dense whitish tomentum that is highly distinctive among pines. Winter buds white, slightly resinous, 1.5-2 cm long, ovoid, pointed. Needles 2 per fascicle, 7-12 cm long, 0.7-1.2 mm wide, acute, dark green, scabrous with minute marginal teeth, often twisted, persisting 3-4 years. Cones short-pedunculate, conic-ovoid, 4-7 cm long, 3.5-6.5 cm wide, buff to brown-gray, opening in late winter. May be single, paired or (in selected cultivars where the pollen cones are replaced by seed cones) very numerous (20 or more) to a shoot. Cone scales numerous, cuneate, the apophysis flattened and transversely rhomboidal, with a short-mucronate umbo, pale brown to buff; the scale stem dark purple-brown to blackish above, pale brown below; opening to 60-80° wide (c.f. P. hwangshanensis), 18-28 mm long, 8-12 mm wide. Seeds dark brown to black, 6 mm, with an articulate 12-16 mm wing (Ohwi 1965, Farjon 1984, M.P. Frankis pers. obs.).

Similar species: P. nigra resembles it in form, foliage, bark and cone characters; see also P. hwangshanensis.

Range

Japan: Honshu, Shikoku and Kyushu; S Korea (Ohwi 1965). It is the dominant pine from the coast to about 1000 m elevation (Richardson and Rundel 1998). USDA hardiness zone 6.

Big tree

Oldest

Dendrochronology

Ethnobotany

Widely used as an ornamental, and requisite in Japanese gardens, where it provides structural and symbolic counterpoint to the red pine P. densiflora.

Air pollution has caused needle chlorosis, reduced needle retention and a decline in community diversity in forests near Korean cities (Richardson and Rundel 1998).

Observations

It is reportedly very common in lowlands within its range. Thanks to its wide popularity as an ornamental, it can be seen through much of the temperate zone.

Remarks

Since the early 20th century, native populations of P. thunbergii have been decimated and may ultimately be eliminated by pine wilt disease, caused by the nematode Busaphelenchus xylophilus. The disease is native to North America, where it has no apparent ill effect on native pines, but the Asian pines P. luchuensis and P. thunbergii apparently have no resistance to it. It is introduced to needles when they are grazed by longhorn beetles (Coleoptera: Cerambycidae) and effectively defoliates the trees. As the trees die and are invaded by blue stain fungi, the nematodes begin to feed on the fungi. Longhorn beetles lay eggs in the bark of the dying trees, providing the nematodes with their transport vector. The nematode is also deadly to P. sylvestris, the world's most widespread pine species, and there is great concern in Europe that the nematode might one day reach that continent (Harrington and Wingfield 1998).

Citations

Harrington and Wingfield in Richardson 1998.

Hsia, W. Y. 1936. Flowering plants of Hwangshan. Contrib. Inst. Bot. Nat. Acad. Peiping 4: 155-156.

Millar in Richardson 1998.

Wakasugi T., Tsudzuki J., Ito S., Nakashima K., Tsudzuki T. and Sugiura M. 1994. Loss of all ndh genes as determined by sequencing the entire chloroplast genome of the black pine Pinus thunbergii. Proceedings of the National Academy of Sciences, USA 91: 9794-9798.

This page co-edited with M.P. Frankis.

See also