The Wind Makes Tub-makers Rich

This is a funny example of chain reaction from a rakugo story of Edo period (17th - middle 19th century).
If a strong wind blows, dust will be raised into the air and will make many people blind. In those days, many of the blind persons played music for a living. So if blind persons increase, SHAMISEN, an instrument with 3 strings, will sell fast. Since cat skin was used for SHAMISEN's body, if SHAMISEN sells well, many cats will be hunted and decrease. (poor cats! I'ma cat lover) If cats are gone, mice will increase and they'll gnaw OKE, wooden tubs, in order to eat foods in them. Then people will buy a lot of new tubs. The wind makes tub-makers rich.

People tell this story to explain that all things are related each other, or things are sometimes caused by the reason which seem to have no relation. And I want to add another lesson of the story to them. Sometimes, someone's benefit is made by the damage of others.

About 50 years ago, with the progress of industry, Japanese government forwarded to cut down the natural woods and recommended to plant cedar trees instead. A Japanese cedar takes only about 40 years to grow to adult tree and is good for construction material. Now there are 4.5 million hectare of artificial forests of cedar in Japan. But in 1960's, importation of lumber was liberalized and price of lumber fell. Since taking care of cedar forest became impossible to pay, they have been left alone. An artificial cedar forest needs to thin out because crowded trees shut out the sunlight and it makes low trees and grasses dead. Bare ground without covering by small plants cannot keep rain water from flowing away fast. So the soil became poor in nutrients and the trees have got thin. Since the roots of trees became weak, landslide has been caused easily.  Many people are killed by landslides every year.

And in recent Japan, the wind makes pharmaceutical companies rich. In the towns and cities of Japan, one of five people has hay fever. It's an allergy to cedar pollen, to be exact.
Cedar trees bloom and sprinkle their pollens in spring. The wind carries the pollens to cities. Since most of the ground in cities are covered with asphalt, pollens don't return to the ground but continue floating in the air. People who have allergic constitution are bothered by symptoms, such as sneezing, runny nose, or itching of eyes. Japanese hay fever is a kind of pollution because it was clearly caused by the failure of the Government's policy. It is also said that exhaust gas in the air has changed our predisposition to be easy to get hay fever.

Some people said that the market scale of the anti-hay fever medicine in Japan is up to about 100 billion yen (950 million USD). However, the loss of the labor earnings of people troubled with hay fever may exceed it.
A certain volunteer organization releases the information about the expected quantity of pollen every year. According to it, in the next year, cedar pollen will be 10 to 15 times as many as this year. Although I myself am not predisposed to hay fever, I seriously sympathize with people who worry about pollen.