Coniferous tree - Shinyoju

Japanese: 針葉樹 - しんようじゅ

A general term for trees with long, thin, hard needle-like leaves. Conifers contain a large amount of resin and are rich in volatile compounds. In botanical classification, they are grouped together with the conifers and yews in gymnosperms. Even though they have long, thin leaves, plants such as Tsugazakura and Erica of the Ericaceae family are not included in conifers.

Conifers usually grow to be tall trees, but there are also shrubs such as the Japanese stone pine, Japanese juniper, and Chinese juniper. Many of their leaves are evergreen, so they are sometimes called evergreen trees, but in species such as larch, the leaves are deciduous. The shape of the leaves varies; in spruce, fir, cedar, and pine, the leaves are narrow and needle-like, while in cypress and aspen, the leaves are scale-like, and in species such as Nagi, the leaves are wide like those of broad-leaved trees. The flowers are unisexual, with female and male flowers, but in pine, cedar, spruce, and fir, both flowers grow on the same plant and are monoecious, while in yew and podocarp, the flowers grow on separate plants and are dioecious. Generally, they produce cones called "matsukasa," but in pine, spruce, and larch, the seeds have wings on one end. The seeds of the yew are wrapped in a fleshy, sweet aril, while those of the podocarpus are hard stone fruits. Other species that produce large seeds include the parana pine.

[Junichiro Samejima]

Ecology

The world's conifers are divided into seven families: Podocarpus, Aucava, Pine, Japanese cedar, Japanese cypress, Araucaria, and Yew, but the six families except for Yew are all grouped together in the class Coniferales (Pinaceae). The Taxaceae family is the only family in the Taxaceae class, and is considered to be a plant that evolved from a very ancient geological period. These seven families are divided into about 50 genera, containing approximately 500 species. Of these, there are six families, 17 genera, and about 40 species in Japan, and three genera, namely, Siberian cypress, Aspergillus dolabrata, and Japanese cedar, are endemic to Japan. The Northern Hemisphere is dominated by the Pinaceae family, followed by the Japanese cedar and the Cupressaceae family. In the Southern Hemisphere, the Podocarpus and Araucaria families are predominant, and contain several important species.

Conifers are said to be more tolerant of poor, dry soils than broad-leaved trees, and many of them have a lower optimum temperature for growth. As a result, they are rare in low latitudes, and in high latitudes, vast coniferous forests of spruce, fir, and larch trees have developed, called taiga. On the other hand, coniferous forests in warmer regions include pine, hemlock, Japanese cedar, and sequoia. Among the main coniferous trees native to Japan, those that are important in forestry are yew, Japanese kaya, cypress, sawara, asunaro, Japanese cedar, Korean pine, black pine, red pine, larch, Ezo spruce, red glehnii, hemlock, Japanese spruce, marsh fir, and todo fir. The most common forestry tree species is Japanese cedar, which is the most widely planted outside of Hokkaido. Japanese cedars are distributed from Yakushima to Aomori Prefecture, and are the largest and longest-lived tree in Japan. In particular, the cedars that grow on Yakushima Island have a breast height diameter of 5 meters, a height of over 30 meters, and are over 2,000 years old. Famous cedar forest areas include Obi (Miyazaki Prefecture), Yoshino (Nara Prefecture), Kitayama (Kyoto Prefecture), Tenryu (Nagano Prefecture, Shizuoka Prefecture), and Akita. Hinoki (Japanese cypress) is said to be the best of all coniferous trees, and the excellence of Japanese wooden architecture is largely due to this tree. Hinoki from Kiso is particularly famous. Akaezo spruce is well-known as a material for musical instruments, and the cypress harvested around Akan is considered to be of good quality. Spruce, fir, and pine trees can be used to make high-quality pulp, but as consumption increases, natural forests are decreasing and artificial forests are being replaced. The sequoia is the tallest gymnosperm in the world, and the largest ones can reach a breast height diameter of 8 meters and a height of around 110 meters. Metasequoia, discovered in China in 1945, is well known as a fossil plant.

[Junichiro Samejima]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

針のように細長く、堅い葉をつける樹木の総称。針葉樹は樹脂を多量に含み、揮発性成分に富んでいる。植物分類上では裸子植物中の球果植物類とイチイ類にまとめられる。細長い葉をもつとはいっても、ツツジ科のツガザクラ、エリカなどは針葉樹には含まれない。

　針葉樹は普通高木になるが、ハイマツ、ハイネズ、リシリビャクシンなどの低木もある。葉は常緑のものが多いため、常磐木(ときわぎ)とよばれることもあるが、カラマツなどでは落葉する。葉の形はさまざまで、トウヒ、モミ、スギ、マツなどでは幅が狭く針状となるが、ヒノキ、アスナロなどでは鱗(りん)状、ナギなどでは広葉樹のように幅広くなる。花は雌花と雄花に分かれる単性花であるが、マツ、スギ、トウヒ、モミなどでは同じ株に両花ともつく雌雄同株であり、イチイ、マキなどではそれぞれの花が別株につく雌雄異株となる。一般に実は「まつかさ」とよばれる球果をつくるが、マツ、トウヒ、カラマツなどでは種子の一端に翅(し)がある。また、イチイの種子は多肉の甘い仮種皮に包まれるし、マキでは堅い石果様となる。大形の種子をつくるものにはパラナマツなどがある。

［鮫島惇一郎］

生態

世界の針葉樹はマキ、イヌガヤ、マツ、スギ、ヒノキ、ナンヨウスギ、イチイの7科に分けられるが、イチイを除く6科はすべて球果植物綱（マツ綱）にまとめられる。イチイ科はイチイ綱に含まれる唯一の科で、系統的にはかなり古い地質時代から分化してきた植物と考えられる。これらの7科は約50属に分けられ、およそ500種を含む。このうち日本には6科17属、約40種があり、コウヤマキ、アスナロ、スギの3属は日本固有のものである。北半球の針葉樹にはマツ科が多く、スギ、ヒノキ科がこれに次いでいる。南半球ではマキ、ナンヨウスギ科のものが多く、いくつかの重要な種を含んでいる。

　針葉樹は広葉樹に比べるとやせた乾燥地によく耐えるとされ、成長の最適温度も低いものが多い。したがって低緯度に少なく、高緯度地帯にタイガとよばれる広大なトウヒ、モミ、カラマツなどの針葉樹林を発達させている。一方、温暖な地域の針葉樹林としてマツ、ツガ、スギ、セコイアなどがある。日本に自生するおもな針葉樹のなかで林業上重要なものは、イチイ、カヤ、ヒノキ、サワラ、アスナロ、スギ、コウヤマキ、クロマツ、アカマツ、カラマツ、エゾマツ、アカエゾマツ、ツガ、トガサワラ、オオシラビソ、トドマツなどである。林業樹種の筆頭はスギで、北海道以外ではいちばん多く植林されている。スギは屋久(やく)島から青森県まで分布し、日本ではもっとも大きく、長寿である。とくに屋久島に生育するスギは胸高直径5メートル、高さ30メートルを超え、樹齢は2000年以上になる。有名なスギ林業地としては飫肥(おび)（宮崎県）、吉野（奈良県）、北山（京都府）、天竜（長野県、静岡県）、秋田などがある。針葉樹材のなかではヒノキが最高といわれ、日本の木造建築の優秀性もこのヒノキに負うところが大きい。とりわけ木曽(きそ)のヒノキは有名である。アカエゾマツは楽器材として定評があり、阿寒(あかん)周辺からとれるものが良材とされる。トウヒ、モミ、マツ属などの材からは良質のパルプがつくられるが、消費の増大に伴い、自然林が減少し人工林化が進んでいる。世界一高くなる裸子植物としてはセコイアがあり、大きなものでは胸高直径8メートル、高さ110メートル前後になる。中国で1945年に発見されたメタセコイアは化石植物としてよく知られる。

［鮫島惇一郎］

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

<<: Letter of credit - Shinyojo (English spelling) letter of credit

>>: Credit union - Shinyo Kumiai