On Tuesday of the 16th I visited the Akatsu Research Unit in University Forest in Aichi of the University of Tokyo. It’s located in the eastern area of Seto connected to the south slope of Mt.Sanage and to the north slope of Mt. Mikuni in Gifu Prefecture.
The main subjects of research there are forest hydrology and erosion control engineering. In particular, the observation and analysis on rainfall and runoff from forested areas has been undertaken.
About 80 years ago, the forest was deserted after mining ceramic clay and cutting down pine trees for firing ceramics. At that time, the area wasn’t a forest, but bare hills. But now the area has become a rich forest completely. However they haven’t plant anything. The forest recovered naturally in 80 years.
The forest is getting bigger and bigger, the humidity is getting higher and higher, and the temperature is getting lower and lower in summer time there.
The main tree was pine tree, but they have ceased to exist by nematodes and lack of the right to sunlight. So the main trees have started changing. If constituent trees change completely, it will affect other plants and creatures. It means us human-being also will be affected in the near future.
I heard an interesting story about allelopathy there. Allelopathy is a phenomenon that the inhibition of growth in one species of plants by chemicals produced by another species, and it’s know among tall goldenrods and walnut trees.
Tall goldenrods have conquered pampas grasses for a long time since they were brought to Japan. But recently tall goldenrods have decreased because allelopathy affects themselves. That’s why many colonies of pampas grasses are increasing all over Japan now. It’s interesting. There are many things I don’t know in this world.