Basal Area — Benchmark Detail

Benchmark Value

5 m²/ha

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 19 benchmarks together — the OptimalRange form drives the primary score, while 18 guard(s) constrain the result.

Contributing Benchmarks

OptimalRange Primary Point Guard MaximumOnly Guard MinimumOnly Guard OptimalRange Guard OptimalRange Guard MaximumOnly Guard MaximumOnly Guard MinimumOnly Guard MaximumOnly Guard OptimalRange Guard MinimumOnly Guard MaximumOnly Guard OptimalRange Guard MinimumOnly Guard Point Guard MinimumOnly Guard MaximumOnly Guard OptimalRange Guard

Evidence & Context

Proposed Lower Critical Threshold: < 5 m²/ha

Metric Definition:

Basal area, defined as the cross-sectional area of tree stems at breast height per unit of land (e.g., m²/ha)

Benchmark Definition:

This benchmark defines the lower critical basal area threshold below which tree density is insufficient to support functional agroecosystem services in agricultural crop production on Australian tropical/subtropical maritime islands.

Justification:

Based on canopy cover minimums and functional ecological studies indicating insufficient tree density below this level

Sources (2)

Preview of Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed July 21, 2025

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed July 21, 2025 Journal

Australian dryland soils are acidic and nutrient-depleted, and have unique microbial communities compared with other drylands - PMC, accessed July 21, 2025

View Source

Preview of Lord Howe Island, NSW 2898 Telephone: (02) 65632066, accessed August 4, 2025,

Lord Howe Island, NSW 2898 Telephone: (02) 65632066, accessed August 4, 2025, Journal

UN Food and Agriculture Organization (FAO) definition of forest canopy cover minimum

View Source

Supporting Sources (4)

Additional references from the underlying research that informed this benchmark.

"A Review of Traditional Agroforestry in Micronesia" (Manner, 1992)

Contextual Support Journal

"A Review of Traditional Agroforestry in Micronesia" (Manner, 1992)

View Source

"Basal area (m²/ha) for different tropical rain forests of the Far East" (Jaffré & Veillon, in Adansonia, 2021)

Contextual Support Journal

"Basal area (m²/ha) for different tropical rain forests of the Far East" (Jaffré & Veillon, in Adansonia, 2021)

View Source

Forestry stocking guides for temperate hardwood stands

Contextual Support Journal

Forestry stocking guides for temperate hardwood stands

View Source

Study in a South Indian agricultural landscape on vegetation cover and crop yield

Contextual Support GreyLiterature

Study in a South Indian agricultural landscape on vegetation cover and crop yield

View Source

Context

Region Australia
Biome Tropical & Subtropical Maritime Islands
Land Use Agricultural Crop Production
Assessment Not Stated
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 8 Jun 2026

Notes

Below this level, tree cover is insufficient to provide significant ecosystem services or form a functional agroecosystem, likely falling below the 10% canopy cover definition of a forest. AssessmentContext defaulted to 'Not Stated' because the source document did not state one.

Related Benchmarks

Other benchmarks in the AUS-TMI-AGR-BAS family.