Soil pH — Benchmark Detail

Benchmark Value

No specific value — see range

Range: 6.5 to 9 pH

Optimal Range: 6.5 to 9

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.

Evidence & Context

For landscapes within the biome that are defined by calcareous parent materials, a naturally higher pH is expected and represents the healthy state for that specific context. The GWW soil profile itself shows pH increasing with depth to 8.5, indicating the presence of alkaline subsoils.

Metric Definition:

Soil pH measured in calcium chloride (CaCl2) solution in topsoil (0-10 cm) for calcareous soils

Benchmark Definition:

This benchmark defines the natural chemical acidity/alkalinity range of calcareous topsoil measured as soil pH in calcium chloride solution for Woodland in Temperate Semi-Arid Shrublands & Open Woodlands under Production Forestry. It reflects the natural alkalinity of calcareous soils as the best available condition.

Justification:

The range reflects the natural alkalinity of calcareous soils as the best available condition rather than an anomaly.

Sources (1)

Preview of Soil | Australia state of the environment 2021, accessed August 12, 2025,

Soil | Australia state of the environment 2021, accessed August 12, 2025, Journal

OzFlux-TERN GWW SuperSite presentation: Soil Chemical Properties

View Source

Supporting Sources (4)

Additional references from the underlying research that informed this benchmark.

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,

Contextual Support Journal

Ecological Thinning Information and Workbook - AWS

View Source

Government of South Australia, Department for Environment and Water. (n.d.). Soil Health and Condition.

Direct Evidence Government

Soil acidity - Department for Environment and Water

View Source

Native Forests Show Resilience to Selective Timber Harvesting in Southeast Queensland, Australia - Frontiers, accessed July 12, 2025,

Contextual Support Journal

The Secret Woodlands That Safeguard Australia's Threatened Birds | The Pew Charitable Trusts

View Source

Sustainable forest management and the ecosystem approach - an ...

Contextual Support Journal

Sustainable forest management and the ecosystem approach - an ...

View Source

Context

Region Australia
Biome Temperate Semi-Arid Shrublands & Open Woodlands
Land Use Production Forestry
Assessment Conservation Target
Vegetation Woodland
Evidence Type ReferenceCondition

Lifecycle

Status Active
Version 1
Effective From 9 Jun 2026

Notes

Lower Critical Threshold: 5.5 pH. No upper detrimental threshold — higher values are always better up to natural saturation. High pH is a natural characteristic of these soils. No evidence for an upper detrimental threshold caused by management.

Related Benchmarks

Other benchmarks in the AUS-TSW-FOR-SPH family.