Resource and non-resource root competition among trees of different successional status

Messier, Christian; Coll, Lluis; Poitras-Larivière, Amélie; Bélanger, Nicolas et Brisson, Jacques (2009). « Resource and non-resource root competition among trees of different successional status ». Journal of Ecology, 97, pp. 548-554.

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Résumé

1. This study assessed the effects of resource (i.e. nutrients) and non-resource (i.e. interference for space) competition from fine roots of competing grasses on the growth, morphology and architecture of fine roots of four tree species of varying successional status: Populus deltoides × P. balsamifera (a hybrid), Betula papyrifera, Acer saccharum and Fraxinus americana. We tested the general hypothesis that tree fine-roots are affected by both below-ground resource and non-resource competition from non-self plants, and the more specific hypothesis that this effect is stronger in early- successional tree species. 2. The experiment was conducted in split-containers where half of the roots of tree seedlings experienced either below-ground resource competition or non-resource competition, or both, by grasses while the other half experienced no competition. 3. The late-successional tree species A. saccharum and F. americana were mostly affected by resource competition, whereas the early-successional P. deltoides × balsamifera and B. papyrifera were strongly affected by both resource and non-resource competition. Non-resource competition reduced fine-root growth, root branching over root length (a measure of root architecture) and specific root length (a measure of root morphology) of both early-successional species. 4. Synthesis. This study suggests that early-successional tree species have been selected for root avoidance or segregation and late-successional tree species for root tolerance of competition as mechanisms to improve below-ground resource uptake in their particular environments. It also contradicts recent studies showing perennial and annual grasses tend to overproduce roots in the presence of non-self conspecific plants. Woody plants, required to grow and develop for long periods in the presence of other plants, may react differently to non-self root competition than perennial or annual grasses that have much shorter lives.

Type:	Article de revue scientifique
Mots-clés ou Sujets:	fine-root competition, root architecture, root avoidance, root morphology, root nutrition, root tolerance, successional tree species
Unité d'appartenance:	Centres institutionnels > Centre d'étude de la forêt (CEF) Faculté des sciences > Département des sciences biologiques
Déposé par:	Christian Messier
Date de dépôt:	20 nov. 2009 21:43
Dernière modification:	01 nov. 2014 02:11
Adresse URL :	http://archipel.uqam.ca/id/eprint/2427

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