Effects of high nitrogen load and ozone on forest tree species
2003
Izuta, T. (Tokyo Univ. of Agriculture and Technology, Fuchu (Japan). Faculty of Agriculture) | Nakaji, T.
Abstract Increases in nitrogen (N) deposition from the atmosphere and tropospheric ozone (O3) concentration are considered to be environmental stresses affecting forest ecosystems. In this paper, we summarized the background of the studies on the effects of N load and O3 on forest tree species, and introduced two experimental studies on the effects of excessive N load and O3, singly and in combination, on growth, physiological functions such as photosynthesis and nutrient status of Japanese red pine (Pinus densiflora). The present situation of atmospheric N deposition and the results of experimental studies suggest that further increase of N deposition to Japanese forest ecosystems at more than the current levels does not always increase tree growth, but depletes the health of sensitive tree species such as Japanese red pine. Furthermore, there is the possibility that increases in the atmospheric N deposition and tropospheric O3 concentration will adversely affect the health of sensitive tree species such as Japanese red pine in the near future.
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