Root development is important to ensure tree survival in conditions of water stress. Despite their longrecognized role, little attention has been given to their development on waste rock slopes subject to rapid drainage. This study was conducted in an open-pit gold mine in a boreal forest. Its main objective was to establish a plantation design allowing a moderate level of competition for water resources in waste rock slopes. A hybrid poplar plantation was established in May 2013 on soil-covered waste rock slopes of 33%. The experimental design included three different tree spacings: 1x1 m, 2x2 m without herbaceous seeding, 2x2 m with herbaceous seeding and 4x4 m. The poplars responded to the increased competition resulting from the closest spacing and the herbaceous seeding by investing less energy in diameter and height growth. Trees that were subject to a higher level of competition were able to acclimatize to water stress conditions by increasing their root length density and specific root length and by reducing their above-ground biomass. This study indicates that some clones of hydrid poplars showing phenotypic plasticity in the ratio of aboveand belowground growth can be adapted for the revegetation of mine sites in the short term.
La bibliothèque du Cégep de l'Abitibi-Témiscamingue et de l'Université du Québec en Abitibi-Témiscamingue (UQAT) a obtenu l'autorisation de l'auteur de ce document afin de diffuser, dans un but non lucratif, une copie de son oeuvre dans Depositum, site d'archives numériques, gratuit et accessible à tous. L'auteur conserve néanmoins ses droits de propriété intellectuelle, dont son droit d'auteur, sur cette oeuvre.
WarningThe library of the Cégep de l'Abitibi-Témiscamingue and the Université du Québec en Abitibi-Témiscamingue (UQAT) obtained the permission of the author to use a copy of this document for nonprofit purposes in order to put it in the open archives Depositum, which is free and accessible to all. The author retains ownership of the copyright on this document.
Root systems are crucial to tree and soil stability in terms of mechanical support, but are rarely considered in revegetation studies. This study aimed at determining the effect of planting density and herbaceous hydroseeding on the root architecture and mechanical resistance to uprooting of planted hybrid poplars on waste rock piles. The study took place at an open pit gold mine in the Canadian boreal zone where a hybrid poplar plantation was established in 2013 on soil-covered waste rock slopes (33%). Four treatments were randomly distributed in three replicated blocks: 4 × 4 m, 2 × 2 m, 1 × 1 m between trees and 2 × 2 m + h, corresponding to trees spaced at 2 × 2 m with hydroseeding. Lateral uprooting tests of four-year-old hybrid poplars were conducted in the direction of the slope. Maximum resistance to the uprooting force was observed in the 2 × 2 m treatment. Root systems were more symmetrical, deep, branched, and had higher root diameters in the 2 × 2 m and 4 × 4 m treatments. In contrast, the treatments with greater intra-or interspecific competition showed shallower, asymmetrical root systems with smaller roots. Therefore, competition significantly reduced tree anchorage.
RÉSUMÉLes systèmes racinaires sont essentiels à la stabilité des arbres et du sol en termes de support mécanique, mais sont rarement considérés dans les études de végétalisation. Cette recherche visait à déterminer l'effet de la densité de plantation et de l'hydroensemencement herbacé sur l'architecture racinaire et la résistance mécanique au déracinement de peupliers hybrides plantés dans les pentes de stériles. L'étude a eu lieu à une mine d'or à ciel ouvert située dans la forêt boréale canadienne. Une plantation de peuplier hybride a été installée en 2013 sur des pentes de stériles recouvertes de sol (3 H:1 V), avec quatre traitements répartis au hasard en trois blocs de répétition : 4 × 4 m, 2 × 2 m et 1 × 1 m d'espacement entre les arbres, ainsi que 2 × 2 m + h correspondant à un espacement de 2 × 2 m avec hydroensemencement herbacé. Des tests d'arrachement latéraux de peupliers hybrides âgés de quatre ans ont été effectués dans le sens de la pente. La résistance maximale à la force d'arrachement a été observée pour le traitement de 2 × 2 m. Les systèmes racinaires étaient plus symétriques, profonds, ramifiés et avaient des diamètres racinaires plus élevés pour les traitements 2 × 2 m et 4 × 4 m. En revanche, les traitements avec une plus grande compétition intra-ou interspécifique ont montré des systèmes racinaires moins profonds, asymétriques et avec des racines plus petites. Par conséquent, la compétition a réduit considérablement l'ancrage des arbres.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.