Fine-root growth in a forested bog is seasonally dynamic, but shallowly distributed in nutrient-poor peat

TitleFine-root growth in a forested bog is seasonally dynamic, but shallowly distributed in nutrient-poor peat
Publication TypeJournal Article
Year of Publication2018
AuthorsIversen CM, Childs J, Norby RJ, Ontl TA, Kolka RK, Brice DJ, McFarlane KJ, Hanson PJ
JournalPlant and Soil
Volume424
Start Page123
Pagination123–143
Date Published03/2018
ISSN0032-079X
Abstract

Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. We aimed to determine how the amount and timing of fine-root growth in a forested, ombrotrophic bog varied across gradients of vegetation density, peat microtopography, and changes in environmental conditions across the growing season and throughout the peat profile.

Methods

We quantified fine-root peak standing crop and growth using non-destructive minirhizotron technology over a two-year period, focusing on the dominant woody species in the bog: Picea marianaLarix laricinaRhododendron groenlandicum, and Chamaedaphne calyculata.

Results

The fine roots of trees and shrubs were concentrated in raised hummock microtopography, with more tree roots associated with greater tree densities and a unimodal peak in shrub roots at intermediate tree densities. Fine-root growth tended to be seasonally dynamic, but shallowly distributed, in a thin layer of nutrient-poor, aerobic peat above the growing season water table level.

Conclusions

The dynamics and distribution of fine roots in this forested ombrotrophic bog varied across space and time in response to biological, edaphic, and climatic conditions, and we expect these relationships to be sensitive to projected environmental changes in northern peatlands.

URLhttp://link.springer.com/10.1007/s11104-017-3231-z
DOI10.1007/s11104-017-3231-z
Short TitlePlant Soil