Plant Trait Target Deriver

Use When

Use this skill when the user gives a plant name such as Limber Pine, maize, or switchgrass and wants a compact trait summary with defensible typical values.

Target outputs

Derive typical values for:

• annual GPP
• LAI
• specific LAI or specific leaf area
• Rubisco Vcmax at 25oC
• Jmax at 25oC
• root-to-shoot ratio
• rooting depth
• leaf protein nitrogen concentration
• leaf chlorophyll nitrogen concentration

Output expectations

Return a compact table or JSON object with:

• plant_name
• accepted_scientific_name
• growth_form
• one row per target trait
• typical_value
• units
• provenance
  • species-sourced
  • genus-inferred
  • functional-type-inferred
  • no-defensible-estimate
• rationale
• source_links

Required behavior

1. Resolve the accepted scientific name first.
2. Determine the growth form:
   • tree
   • shrub
   • grass
   • crop grass
   • forb/herb
3. Search the web using primary and peer-reviewed sources.
4. Prefer species-level values.
5. If species-level values are unavailable, fall back in order:
   • same species in a closely related study system
   • same genus
   • same functional type
6. Label the provenance explicitly.
7. Never present a guessed value as directly measured.

Unit conventions

Use these default units unless the user requests otherwise:

• annual GPP: gC m-2 yr-1
• LAI: m2 leaf m-2 ground
• specific LAI / specific leaf area: m2 gC-1
  • this is the preferred EcoSIM-facing unit
  • if source values use dry-mass units such as m2 kg-1 DW or cm2 g-1 DW, convert to m2 gC-1 only when a defensible carbon fraction is available
  • if conversion is not defensible, report the source value separately and state that the EcoSIM-unit conversion is unresolved
• Vcmax25: umol m-2 s-1
• Jmax25: umol m-2 s-1
• root-to-shoot ratio: kg root kg-1 shoot or unitless mass ratio
• rooting depth: m
• leaf protein nitrogen concentration: g N g-1 leaf or mg N g-1 leaf
• leaf chlorophyll nitrogen concentration: g N g-1 leaf or equivalent chlorophyll-N fraction

If a source reports nitrogen on an area basis rather than mass basis, preserve the source unit unless a clean conversion is possible from the same source.

Search strategy

Before doing substantial work, read references/trait_derivation_guide.md.

Suggested sequence:

1. Taxonomy and growth form:
   • Kew POWO
   • USDA or species-profile sources
2. Productivity and canopy structure:
   • flux, forestry, crop, or ecological studies
3. Photosynthetic traits:
   • peer-reviewed gas-exchange or trait papers
4. Rooting traits:
   • species reviews, crop references, root trait papers
5. Nitrogen allocation traits:
   • leaf economics or crop physiology papers

Trait-specific guidance

• GPP

  • Prefer site- or ecosystem-specific annual ranges for the target species or strongly species-dominated stands.
  • If only NPP or biomass increment is available, do not silently convert to GPP without a defensible method.

• LAI

  • Prefer field studies, flux-site metadata, crop handbooks, or forest canopy studies.

• specific LAI / SLA

  • Treat this as specific leaf area unless the user clearly means something else.
  • State the interpretation explicitly.
  • Prefer the final reported value in m2 gC-1.

• Vcmax25 and Jmax25

  • Prefer values already standardized to 25oC.
  • If a paper reports temperature-response parameters rather than Vcmax25/Jmax25, do not back-calculate unless the paper provides the needed model clearly.

• root-to-shoot ratio

  • Prefer whole-plant or stand-level biomass allocation studies.

• rooting depth

  • Prefer effective or typical maximum rooting depth from species or crop references.
  • Distinguish between observed depth and model-assumed depth when possible.

• leaf protein nitrogen

  • Accept direct protein-N measurements.
  • If only total leaf N is available, do not relabel it as protein N unless the source distinguishes the fraction.

• leaf chlorophyll nitrogen

  • Prefer explicit chlorophyll-N or nitrogen-allocation measurements.
  • If only chlorophyll concentration is reported without nitrogen partitioning, do not convert unless a cited relationship supports it.

Deliverable format

Prefer a flat table with these columns:

• trait
• value
• units
• provenance
• source
• notes

If the user asks for machine-readable output, emit JSON using the schema in references/trait_output_schema.md.

Notes

• This skill is intentionally narrow and should not attempt to derive the entire EcoSIM parameter set.
• Be conservative with Vcmax25, Jmax25, protein N, and chlorophyll N because these are often study-specific.
• Use exact source links in the final answer whenever web evidence is used.