(First upload on December 3 2003. Last on September 15 2015) [ 日本語 | English ]

Rhus trichocarpa Miquel

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Rhus L. (ウルシ, poison oak)

There are three (four) species in Hokkaido
R. ambigua Lavall. ex Dippel (ツタウルシ) = T. orientale
R. javanica L., pro. p. (ヌルデ) (s.l.)
R. succedanea L. (ハゼノキ) = T. succedaneum (L.) Kuntze
R. sylvestris Sieb. et Zucc. (ヤマハゼ) = T. sylvestre (Siebold et Zucc.) Kuntze
R. trichocarpa Miquel (ヤマウルシ) = T. trichocarpum
R. verniciflua Stockes (ウルシ), introduced = T. vernicifluum (Stokes) F. A. Barkley
= Toxicodendron Mill when separated from Rhus

Rhus trichocarpa in Hokkaido

Yama-urushi (ヤマウルシ, 山漆), Japanese sumac
Lifeform: deciduous short-tree
Distribution: China - Korea - southern Sakhalin - Japan
Seed dispersal: animals, in particular, Jungle Crow (Corvus macrorhynchos on Mount Koma (Nishi & Tsuyuzaki 2004)

Toxicodendron trichocarpum (Miquel) Kuntze

f. viridis Hara (アオヤマウルシ)

Rhus1 Rhus2
[1/2] in Shizukari wetland, southern Hokkaido, on June 15 2015.

Mount Koma

Rhus1 Rhus2 Rhus3 1. Seedlings colonized near rocks at 600 m in elevation. 2. Saplings established on a bareland enclosed by the shrub patches of Salix reinii and Gaultheria miqueliana. 3. A fruting tree in a secondary forest at 350 m in elevation (1-5, October 2002)
Rhus4 Rhus5 Rhus6 4. See photo 3. 5. Fruits on the crown throughout winter by aerial seedbank (林冠種子貯蔵) in a secondary forest at 350 m elevation. 6. The fruits soon after ripening become dry and the surface layer is removed. The seed is covered somewhat with wax.
Rhus7 Rhus8 Rhus9 7. A tree with numerous fruits in a secondary forest at 350 m elevation on October 2002. 8. Leaves becoming red earlier than any other broad-leaved trees. Compare to mountainash at the right. 9. R. trichocarpa seedlings at the base of poplar (August 2003).
Rhus10 Rhus11 10. The colonization of seedlings and saplings under a Populus maximowiczii of which height is ca 6 m, before the marking of individuals. 11. To monitor seedlings, numbered tape was tagged on each individual.

H. Nishi took all pictures.