Importance of Arboreal Cyanolichen Abundance to Nitrogen Cycling in Sub-Boreal Spruce and Fir Forests of Central British Columbia, Canada
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Natural Resources and Environmental Studies (NRES) Graduate Program, University of Northern British Columbia (UNBC), 3333 University Way, Prince George, BC V2N 4Z9, Canada
2
NRES Institute
*
Author to whom correspondence should be addressed.
Academic Editor: Heinz Rennenberg
Forests 2015, 6(8), 2588-2607; https://doi.org/10.3390/f6082588
Received: 30 June 2015 / Revised: 19 July 2015 / Accepted: 20 July 2015 / Published: 31 July 2015
(This article belongs to the Special Issue Nitrogen and Phosphorus Nutrition of Trees and Forests)
The importance of N2-fixing arboreal cyanolichens to the nitrogen (N)-balance of sub-boreal interior hybrid spruce (Picea glauca × engelmannii) and subalpine fir (Abies lasiocarpa) forests was examined at field sites in central BC, Canada. Host trees were accessed by a single-rope climbing technique and foliage as well as arboreal macrolichen functional groups were sampled by branch height in eight random sample trees from each of two high (High Cyano) and two low (Low Cyano) cyanolichen abundance sites for a total of 32 sample trees. Natural abundances of stable isotopes of N (15N, 14N) and carbon (13C, 12C) were determined for aggregate host tree and epiphytic lichen samples, as well as representative samples of upper organic and soil horizons (Ae and Bf) from beneath host trees. As expected, N2-fixing cyanolichens had 2–6-fold greater N-contents than chlorolichens and a δ15N close to atmospheric N2, while foliage and chlorolichens were more depleted in 15N. By contrast, soils at all trees and sites were 15N-enriched (positive δ15N), with declining (not significant) δ15N with increased tree-level cyanolichen abundance. Lichen functional groups and tree foliage fell into three distinct groups with respect to δ13C; the tripartite cyanolichen Lobaria pulmonaria (lightest), host-tree needles (intermediate), and bipartite cyanolichens, hair (Alectoria and Bryoria spp.) and chlorolichens (heaviest). Branch height of host trees was an effective predictor of needle δ13C. Our results showed a modest positive correlation between host tree foliage N and cyanolichen abundance, supporting our initial hypothesis that higher cyanolichen abundances would elevate host tree foliar N. Further study is required to determine if high cyanolichen abundance enhances host tree and/or stand-level productivity in sub-boreal forests of central BC, Canada.
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Keywords:
sub-boreal forest nitrogen; δ15N ; δ13C; arboreal lichens; cyanolichens; lichen epiphyte nitrogen; Lobaria pulmonaria
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MDPI and ACS Style
Kobylinski, A.; Fredeen, A.L. Importance of Arboreal Cyanolichen Abundance to Nitrogen Cycling in Sub-Boreal Spruce and Fir Forests of Central British Columbia, Canada. Forests 2015, 6, 2588-2607. https://doi.org/10.3390/f6082588
AMA Style
Kobylinski A, Fredeen AL. Importance of Arboreal Cyanolichen Abundance to Nitrogen Cycling in Sub-Boreal Spruce and Fir Forests of Central British Columbia, Canada. Forests. 2015; 6(8):2588-2607. https://doi.org/10.3390/f6082588
Chicago/Turabian StyleKobylinski, Ania; Fredeen, Arthur L. 2015. "Importance of Arboreal Cyanolichen Abundance to Nitrogen Cycling in Sub-Boreal Spruce and Fir Forests of Central British Columbia, Canada" Forests 6, no. 8: 2588-2607. https://doi.org/10.3390/f6082588
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