Basal Area

AUS-TSR-CON-BAS General High confidence

Benchmark Value

28 m²/ha
Thresholds: Lower: 28, Upper: —
Direction: Higher is desirable ↑
Form: MinimumOnly

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 in the range of 25³28 mb2/ha can be confidently identified as a critical lower boundary.

Metric Definition:

Stand basal area is the sum of the cross-sectional area of all living tree stems, measured at 1.3 meters above the ground (DBH), within a given unit of land area.

Benchmark Definition:

A basal area of 28 m²/ha represents the critical lower boundary below which forest structure and function are compromised in Australian tropical rainforests.

Justification:

Forests with basal areas falling consistently below this level are structurally simplified, show severely compromised recovery potential, and are ecologically degraded.

Sources (1)

Preview of Patterns of basal area increment, mortality and recruitment were ..., accessed July 20, 2025,
Patterns of basal area increment, mortality and recruitment were ..., accessed July 20, 2025, Journal

Patterns of basal area increment, mortality and recruitment were related to logging intensity in subtropical rainforest in Australia over 35 years | Request PDF - ResearchGate

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Supporting Sources (4)

Additional references from the underlying research that informed this benchmark.

Preview of CSIRO Permanent Rainforest Plots of North Queensland, accessed July 20, 2025,
CSIRO Permanent Rainforest Plots of North Queensland, accessed July 20, 2025,
Direct Evidence Government

Estimating the relative magnitude of expected increases in soil ..., accessed July 18, 2025

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Preview of Lowland Rainforest of Subtropical Australia ecological community - conservation advice
Lowland Rainforest of Subtropical Australia ecological community - conservation advice
Contextual Support Government

Lowland Rainforest of Subtropical Australia ecological community - conservation advice

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Preview of Lowland Rainforest of Subtropical Australia ecological community - listing advice
Lowland Rainforest of Subtropical Australia ecological community - listing advice
Contextual Support Journal

Lowland Rainforest of Subtropical Australia ecological community - listing advice

View Source
Preview of Stand basal area, accessed July 12, 2025,
Stand basal area, accessed July 12, 2025,
Contextual Support

Vegetation and floristics of a lowland tropical rainforest in northeast ...

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Context

  • Region Australia
  • Biome Tropical & Subtropical Rainforests
  • Land Use Conservation / Protected Natural Areas
  • Assessment Pristine Reference
  • Evidence Type DegradationThreshold

Lifecycle

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

Notes

This threshold is supported by long-term recovery studies and regulatory proxies.