Effects of chronic nitrogen application on the growth and nutrient status of a Japanese cedar (Cryptomeria japonica) stand

Authors: Nagakura, Junko; Akama, Akio; Mizoguchi, Takeo; Okabe, Hiroaki; Shigenaga, Hidetoshi; Yamanaka, Takashi

Source: Journal of Forest Research, Volume 11, Number 5, October 2006 , pp. 299-304(6)

Publisher: Springer

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Abstract:

To investigate the potential effects of nitrogen (N) deposition on Japanese forests, a chronic N-addition experiment that included three treatments (HNO₃, NH₄NO₃, and control) was carried out in a 20-year-old Japanese cedar (Cryptomeria japonica D. Don) stand in eastern Japan over 7 years. The amount of N applied was 168 kg N ha⁻¹ year⁻¹ on the HNO₃ plots and 336 kg N ha⁻¹ year⁻¹ on the NH₄NO₃ plots. Tree growth, current needle N concentration, and soil solution chemistry were measured. Nitrogen application decreased the pH and increased NO₃ ⁻, Ca²⁺, Mg²⁺, and Al concentrations in the soil solution. The needle N concentration increased in both of the N plots during the first 3 years. Nevertheless, the annual increments in height and in the diameter at breast height of the Japanese cedars were not affected by N application, and no visible signs of stress were detected in the crowns. Our results suggest that young Japanese cedar trees are not deleteriously affected by an excess N load.

Keywords: Andisols; Cryptomeria japonica; Needle nitrogen concentration; Nitrate; Tree growth

Document Type: Research article

DOI: http://dx.doi.org/10.1007/s10310-006-0211-1

Affiliations: 1: Email: kurya@affrc.go.jp

Publication date: 2006-10-01