Basal Area — Benchmark Detail

Benchmark Value

25 m²/ha

Thresholds: Lower: —, Upper: 25

Direction: Higher is desirable ↑

Form: UpperThreshold

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 16 benchmarks together — the OptimalRange form drives the primary score, while 15 guard(s) constrain the result.

Contributing Benchmarks

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

Evidence & Context

Proposed Upper Detrimental Threshold: > 25 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:

The upper detrimental threshold above which basal area causes excessive competition and agricultural failure in tropical and subtropical maritime island agricultural crop production systems.

Justification:

Above 25 m²/ha, intense competition for light, water, and nutrients is highly likely to suppress or eliminate crop yield, making the system agriculturally unviable.

Sources (1)

Forestry stocking guides for temperate hardwood stands Journal

Forestry stocking guides for temperate hardwood stands

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

"Northern hardwood forest management" (MSU Extension, E2769)

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

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

Contextual Support Journal

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

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 Pristine Reference
Evidence Type DegradationThreshold

Lifecycle

Status Active
Version 1
Effective From 22 Mar 2026

Notes

Represents an agro-ecological tipping point where the system shifts from a multifunctional agroforest to a timber plantation with a shaded-out understory.

Related Benchmarks

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