Basal Area

AUS-TDG-FOR-BAS General Moderate confidence

Benchmark Value

No specific value — see range
Range: 10 to 18 m²/ha
Thresholds: Lower: 4, Upper: 25
Optimal Range: 10 to 18
Direction: Higher is desirable ↑
Form: OptimalRange

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 12 benchmarks together — the OptimalRange form drives the primary score, while 11 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary MinimumOnly Guard OptimalRange Guard Point Guard LowerThreshold Guard UpperThreshold Guard OptimalRange Guard OptimalRange Guard MinimumOnly Guard OptimalRange Guard Point Guard MinimumOnly Guard

Evidence & Context

The reference range of 10-18 m²/ha is derived from studies of production forests in temperate dry Australian woodlands where management explicitly aims for ecological health and resilience.

Metric Definition:

Basal area is defined as the sum of the cross-sectional areas of all tree stems in a stand, measured at breast height (typically 1.3 m above ground), and expressed per unit of land area (e.g., m²/ha).

Benchmark Definition:

This benchmark represents the basal area range in production forests of temperate dry Australian woodlands that supports ecological health and resilience, balancing sustainable production with ecological integrity.

Justification:

This range is supported by ecological thinning targets in low-rainfall Jarrah forests and self-thinning limits of key dry woodland species, ensuring stands are not overstocked and can maintain healthy growth.

Sources (1)

Preview of A report on silvicultural guidelines for the 2024- 2033 Forest Management Plan to the Western Australian Department of Biodiversity, Conservation and, accessed July 12, 2025,
A report on silvicultural guidelines for the 2024- 2033 Forest Management Plan to the Western Australian Department of Biodiversity, Conservation and, accessed July 12, 2025, Journal

Growth and recuperative capacity of selectively harvested native forests in southern Queensland (Lewis et al. 2021)

View Source

Supporting Sources (6)

Additional references from the underlying research that informed this benchmark.

Preview of Full article: Active management: a definition and considerations for implementation in forests of temperate Australia - Taylor & Francis Online
Full article: Active management: a definition and considerations for implementation in forests of temperate Australia - Taylor & Francis Online
Contextual Support Journal

Full article: Active management: a definition and considerations for implementation in forests of temperate Australia - Taylor & Francis Online

View Source
Preview of Function Attribute Benchmarks for the Biodiversity Assessment Method: Data audit, compilation and analysis - Environment and Heritage, accessed July 10, 2025,
Function Attribute Benchmarks for the Biodiversity Assessment Method: Data audit, compilation and analysis - Environment and Heritage, accessed July 10, 2025,
Contextual Support

Function Attribute Benchmarks for the Biodiversity Assessment Method: Data audit, compilation and analysis - Environment and Heritage, accessed May 19, 2025

View Source
Preview of Hester, A. J., Pakeman, R. J., Harrison, S., & Ross, L. C. (2017). Thresholds of biodiversity and ecosystem function in a forest ecosystem undergoing dieback. Scientific Reports, 7, 6775.
Hester, A. J., Pakeman, R. J., Harrison, S., & Ross, L. C. (2017). Thresholds of biodiversity and ecosystem function in a forest ecosystem undergoing dieback. Scientific Reports, 7, 6775.
Contextual Support Journal

Across a macro-ecological gradient forest competition is ... - Frontiers

View Source
Preview of Native Forests Show Resilience to Selective Timber Harvesting in Southeast Queensland, Australia - Frontiers
Native Forests Show Resilience to Selective Timber Harvesting in Southeast Queensland, Australia - Frontiers
Contextual Support Journal

Native Forests Show Resilience to Selective Timber Harvesting in Southeast Queensland, Australia - Frontiers

View Source
Preview of Restoration of temperate savannas and woodlands - Forest Service, accessed August 6, 2025,
Restoration of temperate savannas and woodlands - Forest Service, accessed August 6, 2025,
Contextual Support

Restoration of temperate savannas and woodlands - USDA Forest Service, accessed May 19, 2025

View Source
Preview of Thresholds of biodiversity and ecosystem function in a forest ...
Thresholds of biodiversity and ecosystem function in a forest ...
Contextual Support Journal

Thresholds of biodiversity and ecosystem function in a forest ...

View Source

Context

  • Region Australia
  • Biome Temperate Dry Woodlands & Native Grasslands
  • Land Use Production Forestry
  • Assessment Pristine Reference
  • Evidence Type ReferenceCondition

Lifecycle

  • Status Active
  • Version 1
  • Effective From 25 Mar 2026

Notes

Lower Critical Threshold: 4 m²/ha. Upper Detrimental Threshold: 25 m²/ha. The range balances sustainable production with ecological integrity, supporting a relatively open canopy and diverse understorey.