Temporal and spatial variation of fine roots in a northern Australian Eucalyptus tetrodonta savanna

David P. Janos, John Scott, David M.J.S. Bowman

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Six rhizotrons in an Eucalyptus tetrodonta savanna revealed seasonal changes in the abundance of fine roots (≤ 5 mm diameter). Fine roots were almost completely absent from the upper 1 m of soil during the dry season, but proliferated after the onset of wet-season rains. At peak abundance of 3.9 kg m-2 soil surface, fine roots were distributed relatively uniformly throughout 1 m depth, in contrast with many tropical savannas and tropical dry forests in which fine roots are most abundant near the soil surface. After 98% of cumulative annual rainfall had been received, fine roots began to disappear rapidly, such that 76 d later, less than 5.8% of peak abundance remained. The scarcity of fine roots in the upper 1 m of soil early in the dry season suggests that evergreen trees may be able to extract water from below 1 m throughout the dry season. Persistent deep roots together with abundant fine roots in the upper 1 m of soil during the wet season constitute a 'dual' root system. Deep roots might buffer atmospheric CO2 against increase by sequestering carbon at depth in the soil.

Original languageEnglish (US)
Pages (from-to)177-188
Number of pages12
JournalJournal of Tropical Ecology
Volume24
Issue number2
DOIs
StatePublished - Mar 1 2008

Keywords

  • Open forest
  • Rhizotron
  • Root depth profile
  • Root phenology
  • Root-length density
  • Savanna woodland
  • Small roots
  • Traced root abundance

ASJC Scopus subject areas

  • Ecology

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