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Stand productivity and site quality

Site quality metrics (site index at reference age, stand form) and relative productivity classes determining stand productive potential.

Plot-level variables

  • SI — decimal  •  m  •  output: SI

    Site index (dominant stand height at a reference age).

  • SI_ref_age (REF_SI_AGE) — decimal  •  years  •  output: REF_SI_AGE

    Reference age used to calculate the site index of the model.

  • SIUC — decimal  •  m  •  output: SIUC

    Site index uncorrected for planting density (ORGANON model).

  • SF — decimal  •  m  •  output: SF

    Stand form, an alternative to site index estimating site quality from height-diameter relationships (useful for mixed, uneven-aged, or unknown-age stands).

  • SQ — decimal  •  dimensionless  •  output: SQ

    Site quality numerical value ranging from 1 (lowest quality) to 5 (highest quality) [SiTree model special variable].

  • Relative_production_class — integer  •  dimensionless  •  output: RPC

    Categorical relative yield or production class of the stand. Used in the Romania stand model and takes values from 1 to 5.

Tree-level variables

  • SI (site_index) — decimal  •  m  •  output: site_index

    Site quality index or site index assigned at the tree level.

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