Basal Area

AUS-AIF-LVG-BAS General Moderate confidence

Benchmark Value

10 m²/ha
Direction: Higher is desirable ↑
Form: MaximumOnly

Scoring Curve

This curve shows how a field measurement for this indicator would score across all available benchmark forms in this context. The scoring engine uses 18 benchmarks together — the OptimalRange form drives the primary score, while 17 guard(s) constrain the result.

Evidence & Context

Basal area levels exceeding approximately 8.0 to 10.0 m²/ha are associated with "woody thickening," a process recognized as land degradation in grazing contexts.

Metric Definition:

Upper detrimental threshold of tree basal area above which woody thickening causes land degradation.

Benchmark Definition:

This benchmark marks the upper threshold of tree basal area beyond which woody thickening occurs, leading to pasture suppression and reduced livestock carrying capacity in grazing systems.

Justification:

This threshold is supported by management guidelines and ecological studies linking basal area above this range to reduced pasture growth and carrying capacity.

Sources (1)

Preview of Long-term monitoring and modelling of pasture regeneration and water quality from a Bothriochloa pertusa site in the Great Barrier Reef catchments - CSIRO PUBLISHING | The Rangeland Journal, accessed July 15, 2025,
Long-term monitoring and modelling of pasture regeneration and water quality from a Bothriochloa pertusa site in the Great Barrier Reef catchments - CSIRO PUBLISHING | The Rangeland Journal, accessed July 15, 2025, Journal

Reducing the impacts of grazing on water quality - EPA Victoria, accessed July 10, 2025,

View Source

Supporting Sources (3)

Additional references from the underlying research that informed this benchmark.

Preview of Environmental flow requirements in arid zone rivers- A case study from the Lake Eyre Basin, central Australia - ResearchGate
Environmental flow requirements in arid zone rivers- A case study from the Lake Eyre Basin, central Australia - ResearchGate
Contextual Support Journal

Environmental flow requirements in arid zone rivers- A case study from the Lake Eyre Basin, central Australia - ResearchGate

View Source
Preview of Land condition - FutureBeef
Land condition - FutureBeef
Contextual Support GreyLiterature

Rates of erosion and sediment transport in Australia - INTERNATIONAL ASSOCIATION OF HYDROLOGICAL SCIENCES

View Source
Preview of Persistence of in-stream waterholes in ephemeral rivers of tropical northern Australia and potential impacts of climate change - CSIRO PUBLISHING | Marine and Freshwater Research, accessed July 18, 2025,
Persistence of in-stream waterholes in ephemeral rivers of tropical northern Australia and potential impacts of climate change - CSIRO PUBLISHING | Marine and Freshwater Research, accessed July 18, 2025,
Contextual Support Journal

Persistence of in-stream waterholes in ephemeral rivers of tropical northern Australia and potential impacts of climate change - CSIRO PUBLISHING | Marine and Freshwater Research

View Source

Context

  • Region Australia
  • Biome Arid Inland Floodplains & Ephemeral River Systems
  • Land Use Livestock Grazing & Pasture
  • Assessment Not Stated
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 7 Jun 2026

Notes

The upper threshold marks the transition to a degraded state characterized by dense woody vegetation suppressing pasture and reducing livestock carrying capacity. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.