Homo sapience is in extreme ado about COVID-19 these days. But it’s not only we with infectious diseases. Do you remember I posted the problem of Japanese Oak Wilt last summer (on August 23, and September 6, 2019)? At that time, the City had not decided yet what to do with this infectious disease for mighty oaks in Yokohama. Here’s the update. In the end, they cut the tree standing on the popular strolling way in Niiharu Citizen Forest 新治市民の森. Now there is only a stump where I first found the infection.
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| There was a lot of wood powder for the infected tree … |
At that time, I’ve heard it costs fortune to protect forest from the rapidly spreading disease. (It sounds familiar, doesn’t it?) Once infected, it’s hopeless to rescue the tree. The only possible way for humans to guard the rest is to vaccinate them, with the cost of 10,000 yen (USD 100) per tree. (In this regard, oaks are luckier than we with COVID-19 without vaccine.) For 67ha of Niiharu Forest with countless number of trees in oak family, it’s a fortune. My seniors murmured that the City did not have money to do that (,of course). “Well, they cannot leave the tree situated on the most popular road in the forest, can they?” “No, no.” Ultimately the Office has settled in felling the dying tree, but they did not have money to excavate the roots and sanitize the soil. (It is the standard way to treat this disease. Please see my post on August 23.) Having said that, we are not sure if it is wise to take such a complete measure especially for the area in question.
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| The stump of an infected oak. Inside the oak infested with Raffaelea quercivora, the virus spreads like cottony mold to clog vascular cambium rapidly, just like blood clots for heart attack, stroke, et al. Could you see the difference between the whitish core and the reddish rim? Cambium is the outer part of a trunk, and here, they have almost entirely changed the color. This is an evidence the tree was infected by the disease. It was dying … |
Near to that point, there is a place where people could find a plant nearing the extinction and on the red list of IUCN. My seniors told me they have not spotted it for more than 10 years already. But hope springs eternal. If we treat the area chemically, perhaps the probability for us to meet that plant again in Yokohama becomes almost zero ... Though, what would happen this summer in Niiharu without complete treatment against the Oak Wilt? Will we have sudden tree deaths spreading to the entire forest? “Huh, no one knows.” It’s just like us with COVID-19. Who can say for 100% sure Tokyo Olympics and Paralympics will be held in the next year free of global pandemic? Never underestimate viruses …
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| Still, spring has come … Viola keiskei |
If you find environmental issues in Kanagawa Prefecture, please make a contact with Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター
657 Nanasawa, Atsugi City, 243-0121
〒243－0121 厚木市七沢657
Phone: 046-248-0323
You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/
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