Environmental irony: Pollution caused by trees in Japan



So far we only thought of trees as beneficial to our environment. But this belief has been turned upside down. Recently, Cypress and Cedar trees in Japan have been found to be causing massive amounts of nitrogen runoff into local streams. This in turn, is resulting in harmful algae blooms.

Surprisingly, nutrient pollution can be caused due to mismanaged forests. But, it’s not exactly their fault.

Why is this occurring?

The main reason for this occurrence is because these trees are planted in massive commercial plantations. These plantations were established half a century ago when the import of wood by the Japanese companies was at its peak. Many of these plantations have now fallen into a state of disrepair due to negligence. Also, the shift in the market has left an abundance of wood plantations, which are now causing major problems for adjacent wildlife.

How is high concentration of nitrogen in soil harmful?

The older, slowly growing trees use relatively less nutrients (or nitrogen) than younger trees, which grow faster and require more nutrients. Nowadays, rarely any new tree grows in the plantations because the land has become densely populated with older trees which prevent sunlight from nourishing the shorter, nascent trees. In addition, there is an unusually high concentration of nitrogen in the soil on the plantations, which is left to run off into neighboring waterways. As a result, algae blooms have begun to form in the highly nitrogenous marine habitats.

How is algae bloom affecting wildlife?

The algae sucks oxygen out of the water, and therefore, other marine wildlife are unable to survive (a process known as eutrophication). According to the American Society of Agronomy, the problem is widespread. These large plantations account for up to 30 percent of forestland across Japan.

Climate Change is making Trees grow rapidly

A new study penned by Kyushu University’s Masaaki Chiwa, says that the process can be prevented by adequate forest management. Chiwa is encouraging the owners of the large plantations to thin them out and create room for new, smaller trees to utilize the abundant nutrients in the soil. His team is already investigating the impact of recent trimming operations on local waterways. They have been measuring water quality to evaluate any further harmful effects of forest thinning on water quality including nitrogen loss.

This post originally appeared on DSCOVRD.