-橅-
ブナ（山毛欅、橅、椈、桕、学名:Fagus crenata Blume）は、ブナ科ブナ属の落葉高木。
落葉広葉樹で、温帯性落葉広葉樹林の主要構成種、日本の温帯林を代表する樹木。
種小名の crenata は、「円鋸歯状の」を意味する。
中国語で「山毛欅」とは、本種ではなく中国ブナの一種を指す。「橅」は近年作られた日本文字で、一般に（日本）ブナの意味に使われている。「椈」も中国ではブナの意味は全く無く、檜の意味ならあるが、日本ではブナの意味に使われる事がある。別名が、シロブナ、ソバグリ。木材としてはビーチと呼ぶ。
-Brown beech-
The beech (mountain hairy zelkova, brown beech, Japanese beech, scientific name: Fagus crenata Blume) is a tall deciduous tree in the beech family.
It is a deciduous broad-leaved tree, a major constituent species of temperate deciduous broad-leaved forests, and a representative tree of temperate forests in Japan.
The species sub-name crenata means "circular serrated".
The Chinese term "mountain hairy zelkova" refers to a species of Chinese beech, not to this species. The word "beech" is a recently coined Japanese character and is generally used for (Japanese) beech. Japanese beech is not used for beech at all in China, but is used for Japanese beech, although it can mean Japanese cypress. It is also known as white beech and sobagri. As a wood, it is called "beach"
[特徴]
高さ30 mほどに達する落葉高木。樹皮は灰白色できめが細かく、よく地衣類などが着いて、独特の模様のように見える。若い枝は褐色で光沢がある。葉は互生し楕円形（長さ4-9
cm、幅2-4 cm）で、薄くてやや固め、縁は波打っていて、鋸歯と言うよりは葉脈のところで少しくぼんでいる感じになる。秋には黄葉し、その後落葉する。冬芽は褐色の鱗片に包まれ、茎が伸びた後もそれがぶら下がっている。芽から展開した若葉には長い軟毛があり、後に無毛となる。
雌雄同株で、5月ごろに葉の展開と同時に開花する。雄花は枝先からぶら下がった柄の先に6-15個付いて、全体としては房状になる。雌花は本年枝の上部の葉の脇からしっかりした柄の先に上向きにつく。果実は総苞片に包まれて10月頃に成熟し、その殻斗が4裂し散布される。シイの実の表面を少しトゲトゲさせた感じである。殻斗に包まれた2個の果実（堅果）は、断面が三角の痩せた小さなドングリのようなもの。しかしながら、中の胚乳は渋みがなく脂肪分も豊富で美味であり、生のままで食べることもできる。なお、ブナの古名を「そばのき」、ブナの果実を「そばぐり」というのは、果実にソバ（稜角の意の古語）がある木、ソバのある栗の意である。タデ科の作物ソバ（蕎麦）の古名を「そばむぎ」といったのと同様である。
ブナは生長するにしたがって、根から毒素を出していく。そのため、一定の範囲に一番元気なブナだけが残り、残りのブナは衰弱して枯れてしまう。ところが、一定の範囲に2本のブナが双子のように生えている場合がある。これは、一つの実の中に2つある同一の遺伝子を持った種から生長したブナである。
[Features]
A deciduous tree that can reach a height of about 30 m. The bark is grayish-white and fine-grained, often with a lichen-like appearance. The bark is grayish-white and fine-grained, often covered with lichens and other substances, giving it a distinctive pattern. The young branches are brown and shiny. The leaves are alternate and elliptical (4-9 cm long and 2-4 cm wide), thin and somewhat stiff, with wavy edges that are slightly hollowed rather than serrated at the veins. The leaves yellow in autumn and then deciduous. The winter buds are encased in brown scales, which still hang on after the stem has grown. The young leaves that develop from the buds have long pubescence, which later becomes hairless.
The plant is dioecious and blooms in May as the leaves unfold. The male flowers are clustered in clusters with 6-15 flowers at the end of the stem hanging from the ends of branches. Female flowers turn upward on the upper leaf margins of branches this year at the end of the stigma. The fruit ripens in October in bracts, and the funnel is divided into four pieces and scattered around the plant. The surface of the chinquapin fruit is slightly spiked. The two berries encased in the funnel are triangular in cross-section, resembling small, skinny acorns. However, the endosperm inside has no astringency and is rich in fat, and is delicious and can be eaten raw. The ancient name for beech is buckwheat, and the name of its fruit is buckwheat guri, which means buckwheat tree or chestnut with buckwheat in its fruit. This is the same as the ancient name for the buckwheat (buckwheat), a member of the Polygonaceae family.
As the beech grows, it releases toxins from its roots. Therefore, only the most healthy beech remains within a certain range, and the rest of the beech grows weak and dies. However, two beech trees may grow like twins in a certain range. This is a beech that has grown from two identical genetic species in a single fruit.
・種子から発芽した子葉（下）と本葉（上）
Cotyledons (bottom) and leaves (top) that germinated from seeds
・長い軟毛がある若葉、後に無毛となる
Young leaves with long soft hairs, which later become hairless
・垂れ下がる雄花と果実に移行中の雌花
drooping male flowers and female flowers in transition to fruit
[生育]
温帯の山地に生育する。日本では北海道南部、本州、四国、九州に広く分布し、低山の照葉樹林帯と、亜高山の針葉樹林帯の間にはブナ林が成立する。雪が多い日本海側の山地と、奥羽山脈の背稜近くでは、天然林に近いブナ林が広範囲に広がっていたが、戦後大規模に伐採されてしまった。世界遺産に登録された白神山地のブナ林は、保護運動の抵抗により、まとまった天然林としては最後に残ったところである。太平洋側に降りると純林はあまり見られず、ミズナラなど他樹種との混交林をつくる。
本州中部では、ほぼ標高1,000-1,500 mまでの地域がブナ林となる。日本北限のブナ林は、一般的には北海道黒松内町のものが有名であるが、実は最北限のブナ林は隣町の寿都町にある。また、日本のブナの離島北限は奥尻島である。一方、南限のブナ林は鹿児島県高隈山にある。
白神山地以外の広範囲のブナ林としては、岐阜県・石川県・福井県・富山県にまたがる白山、福島県只見町周辺に、広大なブナ林を見る事が出来る。（坪田和人著、「ブナの山旅」「続・ブナの山旅」による）
It grows in temperate mountainous regions. It is widely distributed in southern Hokkaido, Honshu, Shikoku, and Kyushu in Japan, and beech forests are established between the low-mountain deciduous forests and the subalpine coniferous forests. In the snowy mountains on the Sea of Japan side and near the back ridge of the Ou Mountains, there were extensive areas of beech forests that were close to natural forests, but they were extensively logged after the war. The beech forest in the Shirakami Mountains, a World Heritage Site, is the last remaining natural forest that has been consolidated due to resistance from conservationists. Down to the Pacific side, there are not many pure forests, but rather mixed forests with other tree species such as Quercus crispula.
In central Honshu, beech forests cover most of the area up to 1,000 to 1,500 m above sea level. The northern limit of beech forests in Japan is generally known as the one in Kurosatsunai-cho, Hokkaido, but in fact, the northernmost beech forest is located in the neighboring town of Suttsu. In fact, the northern limit of beech forests is located in the neighboring town of Tutu. On the other hand, the southern limit of beech forests is located in Mt.
As for the extensive beech forests outside the Shirakami Mountains, there are vast beech forests in the vicinity of Hakusan, Gifu, Ishikawa, Fukui, and Toyama Prefectures, and Tadami Town, Fukushima Prefecture. (According to Kazuto Tsubota's book, "Beech Mountain Travel" and "Mountain Travel of Beech")
・ブナの4裂した殻斗と堅果 ・Four lobed beech shells andnuts
The beech fruit is important as food for many mammals, and 2003 was a poor year for beech, although it is well known for the large number of Japanese black bears that came into the village. However, the beech crop is basically poor every year, with a good harvest only once every five to ten years. Furthermore, in 2004, when the beech crop was even poorer than in 2003, there were fewer occurrences than in 2003, and in 2005, when there was an unprecedentedly good beech crop nationwide, there were areas where the number of bears increased and areas where the number of bears decreased. From the above, there is a theory that there is no correlation between the appearance of the black bear and the poor harvest of the beech.
[用途]
腐りやすい上に加工後に曲がって狂いやすい性質があり、20世紀の後半まで用材としては好まれなかったが、薪のほか、下等品のための需要はあった。平安時代後期から鎌倉・室町時代にかけては、上質のケヤキにかわるものとして、漆器の椀・皿の普及品の材料として欠かせないものであった。キノコ栽培の原木にも利用されている。
加工需要が増えたのは、薬品処理と合板の出現のおかげである。それでも木材としては価値が低くみられ、日本ではブナの伐採後にスギが植えられてブナ林が縮小した。ただ、曲げに適しているため、家具の脚に好まれる。
家具材（主に脚物家具）、スキー板、ベニヤ材、玩具材、楽器の鍵盤、ブラシの柄などに用いられている。[Use]
Because of its susceptibility to decay and bending after processing, zelkova was not favored as a material for use until the second half of the 20th century, but it was in demand for firewood and other inferior goods. From the late Heian period to the Kamakura and Muromachi periods, it was an indispensable alternative to the fine zelkova wood for making popular lacquerware bowls and plates. It was also used as a raw wood for mushroom cultivation.
The demand for processing increased thanks to chemical treatment and the advent of plywood. Nevertheless, it is still considered to be of low value as a timber, and in Japan, the beech forests shrank when cedar was planted after the beech trees were cut down. However, because it is suitable for bending, it is preferred for furniture legs.
It is used for furniture (mainly legged furniture), skis, veneers, toys, musical instrument keyboards and brush handles.