Paper oak - Paper oak

Japanese: カジノキ - かじのき

A deciduous tall tree of the family Moraceae (APG classification: Moraceae). It grows to a height of over 10 meters, with a trunk diameter of about 60 centimeters. The leaves are broadly ovate with a pointed tip, slightly distorted, shallowly divided into three lobes, about 15 centimeters long, fleshy, rough on the surface, and densely hairy on the underside. The leaves of young trees are palmately divided into three to five lobes, each of which is shallowly incised. In older trees, the leaves become shield-shaped. Dioecious. It blooms in early summer, and the female flower spikes are spherical and purple, about 1.5 centimeters in diameter. The male flower spikes are yellowish-brown, tail-like, about 6 centimeters long, and droop. In autumn, the fruits, which are spherical and gather together, about 2 centimeters in diameter, ripen red. It grows in the mountains of the southern Kanto region, the Tokai region, and the Kinki region and westward, and are distributed in southern mainland China and Taiwan. The same genus of paper mulberry is thought to be a hybrid between the wild species Hime-kozo B. kazinoki Sieb. (which grows in the Kanto region and west and is also simply called kozo) and the paper mulberry. Although the two species look very similar, paper mulberry is monoecious.

The bast fibers extracted from the branches are 5.5-11 mm long and slightly twisted, and are used as the raw material for washi paper, but their quality is inferior to that of kozo. They are mixed with kozo or used for lantern paper and umbrella paper. They used to be cultivated extensively on the edges of fields, but in recent years there has been little demand and agricultural cultivation is no longer seen.

Ink adheres well to the leaves of the paper oak tree, and in the olden days, poems were written on the leaves, especially around the time of Tanabata. Paper oak trees are closely associated with Shinto rituals, and are even used as family crests.

[Hoshikawa Kiyochika December 13, 2019]

Cultural history

It is one of the most useful trees in Polynesia, and following the migration of ethnic groups, it has spread throughout most of Polynesia, with Easter Island being its eastern limit. The bark is made into rope, which is then beaten and stretched into a paper-like form called tapa. Tapa is used for costumes and decorations, and in countries such as Tonga, the tradition remains to this day. Japan once had the same use, where shirotae was made from the paper mulberry, which was called tae. Paper mulberry fruit is edible, and has been excavated from a site dating to the late Jomon period in Hachimanzaki, Aomori Prefecture.

[Hiroshi Yuasa December 13, 2019]

[Reference] | Paper mulberry | Tapa

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

クワ科（APG分類：クワ科）の落葉高木。高さは10メートル以上、幹の直径は約60センチメートル。葉は先のとがった広卵形でややゆがみ、浅く3裂するものが多く、長さ15センチメートルほどで肉厚、表面はざらつき、裏面には毛が密生する。若木の葉は掌状に深く3～5裂し、それぞれの裂片は浅く切れ込む。また老木では、葉は楯(たて)形となる。雌雄異株。初夏に開花し、雌花の穂は直径1.5センチメートルほどの球形、紫色である。雄花の穂は黄褐色で尾状、長さ6センチメートルほどで垂れ下がる。秋に、直径2センチメートルほどの球状に集まった果実が赤く熟す。関東地方南部、東海地方、近畿地方以西の山地に生え、中国大陸南部、台湾に分布する。同属のコウゾは、野生種のヒメコウゾB. kazinoki Sieb.（関東地方以西に自生し、単にコウゾともよばれる）とカジノキとの雑種と考えられている。両者ともよく似ているが、コウゾは雌雄同株。

　枝からとれる靭皮(じんぴ)繊維は、長さ5.5～11ミリメートルで多少のよじれがあり、和紙の原料となるが、品質はコウゾより劣る。コウゾに混ぜたり、提灯(ちょうちん)紙や傘紙に利用される。畑の縁などで粗放栽培されていたが、最近では需要がほとんどなく、農業的栽培はみられなくなった。

　カジノキの葉には墨がよくのり、古くは、とくに七夕(たなばた)のときなどに、葉に歌を書いた。カジノキは神事と関係が深く、家紋にもされている。

［星川清親　2019年12月13日］

文化史

ポリネシアではもっとも有用な木の一つで、民族移動に伴われ、イースター島を東限とするポリネシアのほぼ全域に広がっている。樹皮は綱になり、たたいて紙状に伸ばしタパにする。タパは衣装や飾りに使われ、トンガなどでは現在もその伝統が残る。日本にもかつて同じ用法があり、栲(たえ)とよばれたカジノキから白妙(しろたえ)がつくられた。カジノキの実は食用になり、青森県八幡(はちまん)崎の縄文時代晩期の遺跡から出土している。

［湯浅浩史　2019年12月13日］

[参照項目] | コウゾ | タパ

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例

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