Basal Area

AUS-AIF-LVG-BAS General Moderate confidence

Benchmark Value

8 m²/ha
Thresholds: Lower: —, Upper: 8
Direction: Lower 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 6 benchmarks together — the OptimalRange form drives the primary score, while 5 guard(s) constrain the result.

Evidence & Context

An Upper Detrimental Threshold is well-established; basal area exceeding approximately 8.0 - 10.0 m²/ha signifies "woody thickening," which suppresses pasture, reduces carrying capacity, and is a key indicator of land degradation in grazing systems.

Metric Definition:

Lower boundary of basal area beyond which woody thickening and land degradation occur in grazing systems.

Benchmark Definition:

Threshold basal area indicating onset of woody thickening and degradation in grazed arid woodlands.

Justification:

Based on management guidelines and ecological studies linking basal area above this value to pasture suppression and land degradation.

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

Land condition - FutureBeef

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 Conservation Target
  • Vegetation Woodland
  • Evidence Type DegradationThreshold

Lifecycle

  • Status Active
  • Version 1
  • Effective From 22 Mar 2026

Notes

Exceeding this threshold indicates a shift to degraded land condition with reduced livestock carrying capacity. ConsistencyResolver applied 2026-03-23 00:20 UTC: UpperThreshold → 8 (check: MinAbovePointValue, rationale: Setting UpperThreshold to 8 aligns with the ecological interpretation of this threshold as an upper degradation limit, consistent with the Notes and EvidenceStatement.) ConsistencyResolver applied 2026-03-23 00:20 UTC: LowerThreshold 8 → (check: MinAbovePointValue, rationale: The Notes state 'Exceeding this threshold indicates degradation' and 'An Upper Detrimental Threshold is well-established', indicating this is an upper limit. Moving the value from LowerThreshold to UpperThreshold will auto-correct the form to MaximumOnly, resolving the contradiction.) [Auto-corrected BenchmarkForm: LowerThreshold → MaximumOnly]