Root distribution ofPinus pinaster,P. radiata,Eucalyptus globulusandE. kochiiand associated soil chemistry in agricultural land adjacent to tree lines

Abstract

We quantified the extent and distribution of roots of four commonly planted tree species (Eucalyptus globulus Labill., Pinus radiata D. Don, P. pinaster Aiton and E. kochii Maiden & Blakely subsp. plenissima C.A. Gardner) in agricultural land adjacent to tree lines, and examined the effect of soil type and root pruning on root morphology. Root distribution in soil adjacent to tree lines was mapped by a trench profile method at 13 sites on the south coast of Western Australia. Soil samples were collected to determine water content and fertility. The lateral extent of tree roots ranged from 10 m for E. kochii to 44 m for P. pinaster. This equated to between 1.5 and 2.5 times tree height (H) for E. globulus and Pinus spp. to 4H for E. kochii. Root density declined logarithmically with distance from the trees and was greatest for P. pinaster and least for E. globulus (P < 0.001). The rate of decrease in root density with distance from the trees was greatest for the Pinus spp. and least for E. kochii (P < 0.05). Root density was generally greatest in the top 0.5 m of the soil profile and decreased with increasing depth. This decrease was relatively gradual in the deep sands, but abrupt in clay subsoil. Root dry mass in the sandy top soil beyond 0.5H ranged between 1.0 and 55.5 Mg km(treeline) (-1) for 6-year-old E. kochii and 50-year-old P. pinaster, respectively. Soil water content generally increased with distance from the trees (P < 0.001). There was no evidence of reduced soil fertility in the top 1.4 m of the soil profile adjacent to the trees. Two to four years after trees had been root pruned, both the lateral extent and vertical distribution of roots were similar for pruned and unpruned trees. The density of roots < 2 mm in diameter was greater for root-pruned trees than for unpruned trees (P < 0.05). We conclude that the study species can compete with agricultural crops based on the lateral extent of their roots and the occurrence of greatest root density within 0.5 m of the soil surface.

The use of Eucalyptus in agroforestry systems of southern Rwanda : to integrate of segregate

“…This could probably (Carberry et al, 2007;Hou et al, 2003) and for eucalypts, the common range was observed be attributed to the distance to which the shade extends to. The edge effect distance from tree-crop interface differ between species and sites to be 12 m in Ethiopian highlands (Kidanu et al, 2005) and up to 44 m in Australia (Sudmeyer et al, 2004). The crop field area prone to woodlot tree suppression observed in this study (zone A) is slightly lower than this range.…”

Évaluation d’un modèle semi-empirique pour la prédiction de la biomasse des racines fines dans la végétation composite et complexe d’une zone boisée

“…However, for logistical reasons we could only register the trees within 15 m around the core-sampling points. The maximum radial extent of trees is likely to vary depending on environmental conditions and size of trees but generally ranges from 1.5 to 4 times tree height [22]. In absolute distance terms, eucalypts from semi-arid environments show considerable radial root growth (e.g., ca.…”

“…In absolute distance terms, eucalypts from semi-arid environments show considerable radial root growth (e.g., ca. 20 m for E. camaldulensis [26], up to 39 m in E. globulus [22], in excess of 15-16 m for E. leucoxylon and E. trivalva (cited in Stone and Kalisz [21]). The fact that our modelling and inventory of vegetation around each core were limited to 15 m, could underestimate the potential contribution of plants that are located beyond these distances.…”

“…The fact that our modelling and inventory of vegetation around each core were limited to 15 m, could underestimate the potential contribution of plants that are located beyond these distances. However, since root density declines exponentially with distance from a tree [22], exclusion of the potential contributions of distant plants is unlikely to cause significant underestimation of FRB. Furthermore, the modelled FRB did not show systematic underestimation which would be expected if the maximal radial root spread used in the model (15 m) was less than the actual spread.…”

Perspectives of forest ecophysiological research in the context of Mediterranean Basin

“…Other root functions such as synthesis and storage are considered secondary. Anchorage depends largely on proprieties of the root nearest the stem base and is most significant as a root function install plants, notably trees (Fitter, 1999;Sudmeyer et al, 2004). The ability to acquire resources from soil is a fundamental requirement for all plants, and is determined by four features of root systems: their architecture, their interactions with microorganisms, their ability to influence the rhizosphere by exudation, and their systems for transporting material across membranes.…”