Ah, December, the season of festivity ... “If winter comes, can spring be far behind?” That is to say, the time of year for hay fever is approaching fast. According to the Q&A site of Ministry of Health, Labor and Welfare of Japan, in Kanto Region the main culprits of our sneezing and itchy eyes are pollens of Cryptomeria japonica (cedar) and Japanese cypress. Cedars are used to cause troubles during February - April, and cypresses would do the same during April – May. Though, probably because of global warming, the beginning of the season could be even December and the amount of pollens is becoming larger with warmer climate. I don’t know if it’s true … the Ministry’s website says hay fever due to cedars is very very endemic in Japan. Their document diagnoses 70% of Japanese hay fever patients is due to cedars. Heck. I have to make a schedule to visit my otorhinolaryngologist for prescription … his office is always VERY congested during the hay fever months L.
for hay fever are|
year-round available these days.
a matter of perception …|
the idyllic scenery of Okuyama
… the mass of pollen production site ...
Cedars start producing buds of female flowers in July. When July has fewer rain and lots of sunshine, the number of flower buds of cedars increases, which is a bad omen. During summer, they keep growing and maturing. In mid-October, the female flowers bloom and the male buds start to grow in the same tree. The guys keep maturing and begin spewing out Ø33 microns or so pollens in December or January. The cypresses also start in July the preparation for flowers of next year in a similar way, but they need cold spells to make their male flowers to mature. Dry and sunny July followed by freezing cold winter is ominous sign for sufferers of cypress pollens. In Kanagawa Prefecture, cypress males spurt out pollens of a bit smaller Ø30 microns during March to May. Cedar or cypress, the more vigorous the trees and the more numerous the flowers, the more pollens will be ejected. One saving grace might be when cedars produce lots of pollen early by warm winter, cypresses may not have enough cold weather for theirs. The overall hay fever season could be shorter, with intensive cedar pollens ... L In the current environment in Yokohama, we have no choice other than confronting the problem with medication. S***!
October, the cedars in scion gardens in|
Kanagawa Natural Environment Conservation Center
are already having male and female buds
… They look innocently cute.
The life cycle of cedars and cypresses says we can at least know in the fall of 2016 the condition for 2017 hay fever. One of the perks as a trainee for Kanagawa Forest Volunteer is, we have rather quickly the latest research result done by the professional forest scientists. Dr. Hidetsugu Saitoh of Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター is an expert in the reproduction of trees. Actually, he is the person responsible to the information about pollen counts in Kanagawa. In October 2016, he confidently notified us 2017 is better than 2016 in Kanto Region. i.e. The number of flower buds for cedar and cypress is fewer this year. Come to think of it, we had lots of rain and typhoon last July and August. A-ha.
you see an instrument shelter over there|
at the bottom of this photo?
It’s one of pollen counting facilities in Kanagawa Prefecture.
During the season, the officials of
the Natural Environment Conservation Center
count once a day (normally in the morning)
how many pollens they can find
in 1cm2 of a board situated there.
In one October weekend morning this year,
Dr. Saitoh found one pollen already.
According to him,
one of those sites in the Center will be moved
to Hiratsuka City by the end of 2016
before the serious hay fever comes.
It’s in order to capture more accurately
the condition of residential area, he said.
As an expert, Dr. Saitoh did organize thinning and other forest husbandry to mitigate the clouds of yellow pollens for some time. In the end he reached to the consensus conclusion of forest scientists in Japan: it’s futile to treat adult trees to solve the problem except by massive deforestation. Meanwhile, in Kyushu Island where traditionally cedar and cypress forestry is mainly with propagation by cutting, the problem is smaller due to fewer pollens. So, the possible treatment would be the choice of individual trees that produce fewer or no pollens. The key here is to consider the importance of local gene in trees. Especially for cedars, the locality issue was known for generations. Actually, Japanese forestry policy made a serious blunder in the early 20th century due to ignorance to this fact. (More to this, in a post next year.) Among scientists, the most popular theory for strong localization in Japanese coniferous trees refers to the ecology during the last Glacial Period in the North East Asia. The variation in cedars due to the climate is obvious even for a complete amateur like me. Cedars in the area directly facing to the Sea of Japan / East Sea have very edgy shape as their boughs develop tight to the trunk. They’ve evolved for avoiding the damage caused by wet and heavy snow fall. (Do you know Sea of Japan side in Japan is recording the world heaviest snow falls?) The cedars in the Pacific side are of more easy-going DNA for their boughs spreading (comparatively) wide.
front garden of|
Kanagawa Natural Environment Conservation Center
has several species of coniferous trees
imported from all over the world.
They were expected to be useful for daily lives of Kanagawa,
but the majority of them failed to pass the utility test.
Take the pine trees from Europe shown here.
They came to Japan about 50 years ago
with hope to be pest-resilient shelterbelt
against sand along Shonan Beach.
It turned out they could not withstand strong winds
from the Pacific Ocean.
The beachside forest now is from seedlings of pinus thunbergii,
Japanese and Korean endemic species, found in Kanagawa.
The Europeans in the Center are the remnants of a failed project.
So, Japanese forest scientists of each prefecture are searching for suitable local lineage of less or no pollen trees. In 1996, the prefectural scientists in Chiba identified 13 pedigrees of cedar with fewer pollens. Kanagawa followed Chiba’s pioneering feat with 17 local family lines in 1998, and in 2000 established the scion garden of cedars with fewer pollens, which was the nation’s first. In 2004, all the supply of cedar seedlings in Kanagawa Prefecture was switched to the special scion gardens for fewer pollens. Why such a total control is possible is due to Japanese forestry policy. (I’ll tell you about that later.) Anyway, the quest for fewer or no pollen cedars and cypresses in Kanagawa is continuing for Dr. Saitoh. His story was very interesting. I’ll report his tale more in the next week’s post. J
prefectural model scion garden for less or no pollen cedars.|
Their growth point is cut off
to make them bushy for easier access to flowers = seeds.
Could you see they spread their boughs?
The contact address for Kanagawa Natural Environment Conservation Center 神奈川県自然環境保全センター is
657 Nanasawa, Atsugi City, 243-0121 〒243－0121 厚木市七沢657
You can send an enquiry to them by clicking the bottom line of their homepage at http://www.pref.kanagawa.jp/div/1644/