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Research article - Peer-reviewed, 2020

The role of the understory in litter DOC and nutrient leaching in boreal forests

Hensgens, Geert; Laudon, Hjalmar; Peichl, Matthias; Gil, Itziar Aguinaga; Zhou, Quan; Berggren, Martin

Abstract

Dissolved organic carbon (DOC) derived from plant litter plays an important role in the ecosystem carbon balance and soil biogeochemistry. However, in boreal coniferous forests no integrated understanding exists of how understory vegetation contributes to litter leaching of DOC, nitrogen (N) and phosphorus (P) with different bioavailability at the forest stand level. We characterized water extractable leachates from fresh and decayed litter of dominant canopy and understory sources in a boreal coniferous forest, in order to explore the contribution of understory vegetation as a source of both total and bioavailable forms of DOC, N and P. Recently produced litter from deciduous species (including Vaccinium myrtillus) yielded the highest amounts of DOC. However, this leaching potential decreased exponentially with mass loss through litter decay. The DOC lability generally showed little interspecific variation, although wood derived DOC was more recalcitrant. Lability decreased progressively with litter aging. Water extractable nutrients increased proportionally with DOC, and roughly a quarter (N) or half (P) had directly bioavailable inorganic forms. Scaled to annual litterfall at the forest stand, understory vegetation contributed 80% of the water extractable DOC and nutrients from fresh litter, with > 60% coming from Vaccinium myrtillus alone. However, as litter decomposes, the data suggest a lower leaching potential is maintained with a larger contribution from needle, wood and moss litter. Our study shows that understory vegetation, especially V. myrtillus, is a key driver of litter DOC and nutrient leaching in boreal coniferous forests.

Keywords

Boreal forest; Dissolved organic carbon; Fennoscandia; Leaching; Litter; V. myrtillus

Published in

Biogeochemistry
2020, volume: 149, pages: 87-103
Publisher: SPRINGER

Authors' information

Hensgens, Geert
Lund Univ
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Gil, Itziar Aguinaga
Wageningen Univ
Zhou, Quan
Wageningen Univ
Berggren, Martin
Lund Univ

UKÄ Subject classification

Forest Science

Publication Identifiers

DOI: https://doi.org/10.1007/s10533-020-00668-5

URI (permanent link to this page)

https://res.slu.se/id/publ/105606