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Abstract

The relative abundance of nitrogen-fixing species has been hypothesised to influence tree biomass, decomposition, and nitrogen availability in eucalypt forests. This prediction has been demonstrated in experimental settings (two-species mixtures) but is yet to be observed in the field with more realistically complex communities. We used a combination of (a) field measurements of tree-community composition, (b) sampling of soil from a subset of these sites (i.e., the local environment), and (c) a decomposition experiment of forest litter to examine whether there is a local-scale effect of the nitrogen-fixing Acacia dealbata Link (presence and abundance) on nitrogen availability, and whether increases in this essential nutrient led to greater biomass of the canopy tree species, Eucalyptus obliqua L’Hér. Average A. dealbata tree size was a significant predictor of forest basal area in 24 plots (12% deviance explained) and, when combined with average distance between trees, explained 29.1% variance in E. obliqua biomass. However, static patterns of local nitrogen concentration were unrelated to the presence or size of A. dealbata, despite our experiments showing that A. dealbata leaf litter controls decomposition rates in the soil (due to three times higher N). Such results are important for forest management in the context of understanding the timing and turnover of shorter-lived species like acacias, where higher N (through either litter or soil) might be better detected early in community establishment (when growth is faster and intraspecific competition more intense) but with that early signal subsequently dissipated.

Item Type:	Article
Authors/Creators:	Buettel, JC and Ringwaldt, EM and Hovenden, MJ and Brook, BW
Keywords:	forests, nutrients, disturbance, management, diversity, biomass, forest productivity, community evenness, eucalypt, terrestrial ecology, complementarity
Journal or Publication Title:	Forests
Publisher:	MDPI
ISSN:	1999-4907
DOI / ID Number:	https://doi.org/10.3390/f10040340
Copyright Information:	Copyright 2019 The Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/
Related URLs:	Google Scholar: Buettel, JC Google Scholar: Hovenden, MJ UTAS Profile: Hovenden, MJ Google Scholar: Brook, BW UTAS Profile: Brook, BW
Item Statistics:	View statistics for this item

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