Abstract
We compared the leaf properties of four tree species (Japanese cedar, hinoki cypress, and two deciduous hardwood species) at sites in Tsukuba (a high nitrogen-deposition area) and Katsura (a low nitrogen-deposition area) in the Kanto district of Japan. Nitrogen concentration in fresh leaves of Japanese cedar did not differ between the two sites, whereas those for the other three species were higher at Tsukuba than at Katsura. Leaf mass per area of hinoki cypress and the two deciduous hardwood species was lower at Tsukuba than at Katsura, but the effects on leaf nitrogen content per area varied among tree species. The nitrogen resorption efficiency of Japanese cedar was lower at Tsukuba than at Katsura, but there was no clear difference in the other three species. The nitrogen isotope ratio in all species was higher at Tsukuba than at Katsura, but the carbon isotope ratio did not differ between the two sites. These results suggested that the effects of nitrogen deposition on leaf properties varied among tree species and that Japanese cedar at Tsukuba was in a more nitrogen-saturated condition than were the other three species.
