記事詳細
喜多智靖さんは木のお医者さん、「樹木医」という仕事をしている。根がおかしくなっていないか穴を掘って見たり、木にあいた穴をふさいだり、元気のない木に薬をぬったり、人間にするのと同じように木の治療をする。私が通う大街道小学校のほか、鹿妻小学校の木の治療もしてくれている。木と津波による塩害のお話を聞いた。
木には弱点が3つある。1つ目は木の表面。木は表面が枯れると、どんどん弱っていくので薬をぬるのはとても大事な仕事だ。2つ目は穴。木の幹は直径の70 %より大きい穴があいていると、台風などですぐに倒れてしまう。3つ目は根をいじめられるのに弱い。特に海水にも弱い。海水をかけられると、海水の中の塩のせいで、土の中が固くなって水がたまってしまう。その結果、多すぎる水で根が弱ってしまう。
このような木を救う方法は3つ。1つ目は、水をたくさんかけて海水と一緒に流す方法、2つ目は、流れやすくする薬をかけて1つ目と同じことをする方法、3つ目は、海水、つまり、塩が大好きな植物に吸い取ってもらうという方法だ。
私たちは喜多さんと一緒に住吉公園に行き、塩害で枯れてしまった木を見た。今回の津波で、どれだけの木が塩害にあって枯れてしまったのか正確なデータはまだないそうだが、石巻の場合、平野部の約30 %が浸水したから塩害で苦しんでいる木はすごく多いと考えられる。これからも、喜多さんのような木のお医者さんがたくさん活躍して、塩害にあった木だけでなく、世界中の木を救ってほしい。
最後に、喜多さんが、トトロの住んでいる「くすのき」が一体何才なのか？を説明してくれた。トトロの身長は約2㍍、体重は約1、000㌔㌘と考えられている。トトロの住んでいる木の穴は約6㍍で、木の太さは8・6㍍ぐらい。木は、1年で3㍉㍍ずつ、両側で6㍉㍍太くなるから、8、600㍉㍍÷6㍉㍍＝1、433となる。なんと、トトロのくすのきは1、433才以上だということになる！ちなみに、存在する木で一番長生きなのは9、550才ぐらいだそうだ。
取材・文：村松 鈴音（大街道小学校６年生）
2013/12/11
Healthy Trees for Green Ishinomaki!
Tree surgeon Kita’s struggle
Rinne Muramatsu, 6 th Grade, Okaido Elementary School
Kita Tomoyasu works as a tree surgeon, a type of tree doctor. He does things like dig holes to check whether the roots are healthy, stops up holes that appear, applies medicines to the sick trees, and treats them like a doctor would treat a person. Kita treats the trees of my school Okaido Elementary as well as those of Kazuma Elementary School. He spoke to us about the salt damage to the trees caused by the tsunami.
Every tree has three weak points. Firstly, on the outside; if it is withering then it is slowly getting weaker, and it is an important job to apply medicine. Secondly, there are the holes. If a tree is more than 70% hollow across its diameter, it could easily be blown down by a typhoon or strong wind. Thirdly, the roots. If the roots are ill-treated, the tree will also become weak. Sea water in particular damages it. Because of the salt content in sea water, the soil becomes hard and the water builds up. As a result, due to too much water, the roots become weaker.
There are three methods for saving trees like these. The first is, apply lots of water to wash away the sea water. The second is the same as the first, but uses medicines that allow the salt water to be drained away easily. The third, is to use plants that like salt water to absorb it.
We all went with Kita to the Sumiyoshi Park, and saw the trees that had suffered salt damage. There is no accurate data yet as to much damage the trees have suffered due to the salt from the recent tsunami, but in the case of Ishinomaki, it is thought that a great many trees have been damaged, as about 30% of flat land was submerged by water. After this, I hope that tree surgeons like Kita will work hard not only to save trees hit by salt damage, as well as those facing other threats the world over.
Finally, Kita explained to us the answer to the question, “Just how old is the camphor tree that the anime character “My Neighbour Totoro” lives in?” We think that Totoro is about 2 meters tall and weighs about 1000kg. The hollow inside of the trunk is about 6 metres, and the thickness of the tree is about 8.6 metres. As trees grow about 3mm thicker a year, on both sides about 6mm, that amounts to 8600mm divided by 6 = 1433 years. So that means that Totoro’s camphor tree is actually over 1433 years old! By the way, the tree that has lived the longest is said to be 9550 years old.
(Translation: Brigitte Cann, Angus Turvill, Kevin Squibb, Claire Thompson, Jennifer Hikari Dixon)