PS 12-115
Growth effort and soil nitrogen availability drive age-related patterns in nitrogen resorption in a Larix Principis-rupprechtii plantation

Monday, August 10, 2015
Exhibit Hall, Baltimore Convention Center
Zhenzhong Sun, College of Urban and Environmental Sciences, Peking university, Beijing, China
Shilong Piao, College of Urban and Environmental Sciences, Peking University, Beijing, China

Nitrogen (N) resorption as a key strategy for conserving N in forests, and is associated with stand development. However, our understanding of the age-related pattern of N resorption, and what drives the pattern in temperate forests, is limited. Here, we evaluated green- and senesced-leaf N concentrations and the nitrogen resorption efficiency (NRE) of Larix Principis-rupprechtii forest stands in different age classes (2, 11, 20, 45, and 100 years old) in a plantation in north China. We also examined the effects of the annual N requirement for tree growth and soil dissolved N concentration on N resorption.


We found a logarithmic increase in NRE and green leaf N concentration, and a logarithmic decrease in senesced-leaf N concentration along the stand-age chronosequence. Based on the study of 11-, 20-, and 45-year-old stands, the annual N requirement for tree growth positively affected N resorption, and the soil dissolved N concentration negatively affected NRE in a forest at the three stand ages. In addition, a 4-year exogenous N input experiment showed that the mean NREs in the 11- and 20-year-old stands decreased following a 50 kg N ha-1 yr-1 input. However, a similar response of NRE was not observed in the 45-year-old stand. These results not only imply that the trees could adjust their N resorption efficiency with stand development but also indicate that ignoring the age-related pattern of N resorption can lead to a bias in N cycle models when evaluating forest net primary production under increasing global N deposition.