Impact of Nitrogen Fertilization on Forest Carbon Sequestration and Water Loss in a Chronosequence of Three Douglas-Fir Stands in the Pacific Northwest

Forests

Xianming Dou⁴  Baozhang Chen⁴  T. Andrew Black²  Rachhpal S. Jassal²  Mingliang Che³  Heinz Rennenberg¹ 

[1] School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China; E-Mail;Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; E-Mails:;State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Nature Resources Research, University of Chinese Academy of Sciences, Beijing 100101, China; E-Mail:;School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China; E-Mail:

关键词: forest fertilization;    carbon sequestration;    evapotranspiration;    water use efficiency;    light use efficiency;    artificial neural network;   

DOI  :  10.3390/f6061897

来源: mdpi

【 摘 要 】

To examine the effect of nitrogen (N) fertilization on forest carbon (C) sequestration and water loss, we used an artificial neural network model to estimate C fluxes and evapotranspiration (ET) in response to N fertilization during four post-fertilization years in a Pacific Northwest chronosequence of three Douglas-fir stands aged 61, 22 and 10 years old in 2010 (DF49, HDF88 and HDF00, respectively). Results showed that N fertilization increased gross primary productivity (GPP) for all three sites in all four years with the largest absolute increase at HDF00 followed by HDF88. Ecosystem respiration increased in all four years at HDF00, but decreased over the last three years at HDF88 and over all four years at DF49. As a result, fertilization increased the net ecosystem productivity of all three stands with the largest increase at HDF88, followed by DF49. Fertilization had no discernible effect on ET in any of the stands. Consequently, fertilization increased water use efficiency (WUE) in all four post-fertilization years at all three sites and also increased light use efficiency (LUE) of all the stands, especially HDF00. Our results suggest that the effects of fertilization on forest C sequestration and water loss may be associated with stand age and fertilization; the two younger stands appeared to be more efficient than the older stand with respect to GPP, WUE and LUE.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.