Ecophysiological responses of the larch species in northern Japan to environmental changes as a basis for afforestation

For sustainable use and suitable management of larch plantations, we must clarify the ecophysiological responses of larch species to environmental changes. The physical environment has been changing dramatically, e.g., increase in atmospheric CO₂ concentration (CO₂]), nitrogen (N) deposition, and atmospheric ozone concentration (O₃]), and these changes may negatively affect growth of larch species. This review summarizes the previous experimental studies on the ecophysiological responses of larch species to elevated CO₂], soil acidification, elevated O₃], and N load. Based on the advanced studies, although elevated CO₂] will stimulate the productivity of larch, increase of O₃] and severe soil acidification will reduce it. Increase of N deposition, at least, will not negatively affect larch productivity. Finally, we propose the future direction for investigation to understand the mechanism of the responses of larch species and to predict the associated risk.