Abstract
Research survey was conducted in Tama Hills and Kamakura, suburban areas, where nitrogen saturation has been reported, and in Oku-Chichibu, a mountain range, to determine the quantitative effect of dissolve inorganic nitrogen (DIN; [NO3 -N]+[NH4 -N]) and dissolved organic nitrogen (DON) on Japanese cedar (Cryptomeria japonica) forest canopies. The total nitrogen value in through fall was 32.2 and 47.2 in the Tama Hills and Kamakura areas, respectively (unit: kg N ha-1 yr-1). DIN values were significantly higher in the suburban areas than in the mountain range. In the suburban areas, the DIN increased due to dry deposition. Similar DON values were obtained in all the research areas, including slightly larger DON values in older trees.
