deCordova Japanese Cedar

The Japanese Cedar, Peacock Pine or Sugi — actually a member of the Cypress family — is the national tree of Japan. This tree of immense cultural importance is planted around temples and believed to be visited by deities on festival days. Small shrines are set on the trunks of old Sugi trees to reflect their spiritual significance. Recently, the Japanese have recognized the importance of old Sugis, which sometimes reach heights of 100 feet and 2,000 years of age, leading to unusual attempts to conserve them such as having special doctors care for them.

But this tree is both beloved and despised in modern Japan. After WWII, a program to reforest Japan’s mountainsides led to massive plantings of both Sugi and Hinoki trees. Millions of people endure weeks of hay fever every year, brought on by the clouds of pollen from these trees. The now unmanaged forests are also causing extensive pollution. The lack of care, added to the fact the trees are all of similar size, cause heavy shading, preventing vegetation from growing beneath them. Not needed by mature trees, the excess nitrogen from decaying organic matter collects in the forest soil. With almost no vegetation to absorb it, the nitrogen washes away during rainstorms, and the runoffs generate huge algal blooms at sea, creating “dead zones,” where little survives.

Some say these runoffs are as harmful to the environment as the nitrogen fertilizer runoffs from industries. Some of these forests are now being thinned so that other plants can stand a chance and promote richer ecosystems. Unfortunately, overall, little flora and fauna can survive in these areas — at least for now.