Poor management led to overcrowded, older trees with little understory
Most of us don’t consider forests a source of pollution. As natural bodies, they should be good for the environment. But a recent study in Japan shows that older cedar and cypress plantations are causing as much pollution as a poorly managed agricultural field or urban setting.
Masaaki Chiwa is the lead author of the study and an assistant professor at Kyushu University in Japan. According to Chiwa, the pollution is not the fault of the trees. It’s the management of the plantations. In Japan, as in other countries, natural forests usually play a significant role in maintaining water quality.
“Many Japanese cedar and Japanese cypress plantations were established in the 1950s and 1960s—60% of those on private land,” according to Chiwa. “These are not natural forests; they were meant for commercial purposes.”
At the time of their planting, there was a short supply of these trees. However, an increase in imports of other woods has affected prices of Japanese cedar and cypress and led to the decline in active plantation management. The result was overcrowded land with aging trees and little to no undergrowth.
These older plantations are now a source of non-point nitrogen pollution according to the study. “Point” pollution comes from a single location; “non-point” pollution comes from a more diffuse area, such as these plantations. The nitrogen is flowing from the plantations during rainfalls or snowmelts into nearby bodies of water, causing algae blooms.
Where does all this nitrogen come from? Just like in a natural forest, needles fall from the aging trees and accumulate on the plantation floor. This is part of Mother Nature’s way of recycling nutrients. Earthworms and soil microbes decompose the needles and return the nutrients to the soil. Younger growth nearby finishes the process and takes up the nutrients.
However, the age of the trees in these plantations means they are growing more slowly. They use fewer nutrients from the soil than younger trees, including nitrogen. Furthermore, crowding of the trees means there is too much shade to encourage new growth. This prevents a new, healthy understory that would use the nitrogen (and other nutrients) from the soil. Because the plants are not using the nutrients, the nutrients form runoff heading to the streams.
Since cedar and cypress plantations account for 30% of the forestland in Japan, the findings of this study are significant. Chiwa and his team would recommend that the plantation land be thinned and returned to a more natural forest state.
As part of another project, some landowners thinned plantations in 2012. To verify that the thinning will reduce runoff, Chiwa and his team are now measuring the amount of nitrogen flowing from the plantations. “We have been measuring water quality to evaluate the effect of forest thinning on water quality including nitrogen loss.”
Hopefully, better management will bring these plantations back to a less-crowded, more natural state, and restore their ability to clean water rather than pollute it.
The study was published in the Journal of Environmental Quality.
Public and Science Communications Director
Susan Fisk | newswise
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences