Basal Area

AUS-TGP-CON-BAS General Moderate confidence

Benchmark Value

3 m²/ha
Thresholds: Lower: —, Upper: 3
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 5 benchmarks together — the OptimalRange form drives the primary score, while 4 guard(s) constrain the result.

Evidence & Context

A basal area of < 3 m²/ha can be established as a conservative and defensible lower critical threshold.

Metric Definition:

Basal area is the total cross-sectional area of all tree stems in a given area, measured at breast height.

Benchmark Definition:

This benchmark defines a lower critical threshold of 3 m²/ha basal area, below which the ecosystem transitions to a derived grassland, losing its woodland character.

Justification:

This value is significantly below the basal areas observed in healthy old-growth remnants and even substantially lower than the most aggressive thinning targets in restoration projects.

Sources (1)

Preview of National Recovery Plan for White Box–Yellow Box ... - DCCEEW, accessed August 11, 2025
National Recovery Plan for White Box–Yellow Box ... - DCCEEW, accessed August 11, 2025 Journal

Approved Conservation Advice for the White Box - Yellow Box - Blakely's Red Gum Grassy Woodland and Derived Native Grassland - DCCEEW

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Supporting Sources (1)

Additional references from the underlying research that informed this benchmark.

Preview of Ecological Thinning Trial in New South Wales and Victorian River Red Gum Forests - Environment and Heritage
Ecological Thinning Trial in New South Wales and Victorian River Red Gum Forests - Environment and Heritage
Direct Evidence

Ecological Thinning Trial in New South Wales and Victorian River Red Gum Forests - Environment and Heritage

View Source

Context

  • Region Australia
  • Biome Temperate Grassy Woodlands & Plains
  • Land Use Conservation / Protected Natural Areas
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

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

Notes

Below this threshold, the ecosystem transitions to a derived grassland, losing its woodland character.