title: Nitrogen dynamics in managed boreal forests: Recent advances and future research directions.
abstract: Nitrogen (N) availability plays multiple roles in the boreal landscape, as a limiting nutrient to forest growth, determinant of terrestrial biodiversity, and agent of eutrophication in aquatic ecosystems. We review existing research on forest N dynamics in northern landscapes and address the effects of management and environmental change on internal cycling and export. Current research foci include resolving the nutritional importance of different N forms to trees and establishing how tree-mycorrhizal relationships influence N limitation. In addition, understanding how forest responses to external N inputs are mediated by above- and belowground ecosystem compartments remains an important challenge. Finally, forestry generates a mosaic of successional patches in managed forest landscapes, with differing levels of N input, biological demand, and hydrological loss. The balance among these processes influences the temporal patterns of stream water chemistry and the long-term viability of forest growth. Ultimately, managing forests to keep pace with increasing demands for biomass production, while minimizing environmental degradation, will require multi-scale and interdisciplinary perspectives on landscape N dynamics.
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, 901 87, Umeå, Sweden. ryan.sponseller@umu.se.
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Sponseller
authors.affiliation: Department of Forest Ecology and Mangement, SLU, Skogsmarksgränd, 901 83, Umeå, Sweden. michael.gundale@slu.se.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gundale
authors.affiliation: Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, 750 07, Uppsala, Sweden. martyn.futter@slu.se.
authors.forename: Martyn
authors.initials: M
authors.lastname: Futter
authors.affiliation: Skogforsk, Uppsala Science Park, 751 83, Uppsala, Sweden. eva.ring@skogforsk.se.
authors.forename: Eva
authors.initials: E
authors.lastname: Ring
authors.affiliation: Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden. annika.nordin@slu.se.
authors.forename: Annika
authors.initials: A
authors.lastname: Nordin
authors.affiliation: Department of Forest Ecology and Mangement, SLU, Skogsmarksgränd, 901 83, Umeå, Sweden. torgny.nasholm@slu.se.
authors.forename: Torgny
authors.initials: T
authors.lastname: Näsholm
authors.affiliation: Department of Forest Ecology and Mangement, SLU, Skogsmarksgränd, 901 83, Umeå, Sweden. hjalmar.laudon@slu.se.
authors.forename: Hjalmar
authors.initials: H
authors.lastname: Laudon
mesh_terms: D005387:Finland; D016468:Forestry / Q000379:methods* / Q000639:trends; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D058458:Nitrogen Cycle; D009586:Nitrogen Fixation; D013548:Sweden; D066188:Taiga
chemical_list: D009584:Nitrogen
keywords: Boreal forests; Clear cutting; Forest management; Nitrogen fixation; Plant–soil interactions; Watersheds