/// <summary>
/// Find cubic volume of tree per hectare.
/// </summary>
/// <param name="trees">Trees in stand.</param>
/// <param name="treeIndex">Tree.</param>
/// <returns>Cubic volume including top and stump in m³/ha.</returns>
public static float GetCubicVolume(Trees trees, int treeIndex)
{
float dbhInCm = trees.Dbh[treeIndex];
float heightInM = trees.Height[treeIndex];
float expansionFactor = trees.LiveExpansionFactor[treeIndex];
if (trees.Units == Units.English)
{
dbhInCm *= Constant.CentimetersPerInch;
heightInM *= Constant.MetersPerFoot;
expansionFactor *= Constant.AcresPerHectare;
}
if (dbhInCm <= 0.0F)
{
Debug.Assert(dbhInCm == 0.0F);
return(0.0F);
}
float cvtsPerTreeInCubicM = trees.Species switch
{
// Poudel K, Temesgen H, Gray AN. 2018. Estimating upper stem diameters and volume of Douglas-fir and Western hemlock
// trees in the Pacific northwest. Forest Ecosystems 5:16. https://doi.org/10.1186/s40663-018-0134-2
// Table 8
FiaCode.PseudotsugaMenziesii => MathV.Exp(-9.70405F + 1.61812F * MathV.Ln(dbhInCm) + 1.21071F * MathV.Ln(heightInM)),
FiaCode.TsugaHeterophylla => MathV.Exp(-9.98200F + 1.37228F * MathV.Ln(dbhInCm) + 1.57319F * MathV.Ln(heightInM)),
_ => throw Trees.CreateUnhandledSpeciesException(trees.Species),
};
return(expansionFactor * cvtsPerTreeInCubicM);
}
/// <summary>
/// Find cubic volume of tree.
/// </summary>
/// <param name="trees">Trees in stand.</param>
/// <param name="treeIndex">Tree.</param>
/// <returns>Tree's volume including top and stump in ft³.</returns>
public static float GetCubicFeet(Trees trees, int treeIndex)
{
if (trees.Units != Units.English)
{
throw new NotSupportedException();
}
float dbhInInches = trees.Dbh[treeIndex];
if (dbhInInches < Constant.InchesPerCentimeter * Constant.Bucking.MinimumScalingDiameter4Saw)
{
return(0.0F);
}
float logDbhInInches = MathV.Log10(dbhInInches);
float heightInFeet = trees.Height[treeIndex];
float logHeightInFeet = MathV.Log10(heightInFeet);
float cvtsl = trees.Species switch
{
// Waddell K, Campbell K, Kuegler O, Christensen G. 2014. FIA Volume Equation documentation updated on 9-19-2014:
// Volume estimation for PNW Databases NIMS and FIADB. https://ww3.arb.ca.gov/cc/capandtrade/offsets/copupdatereferences/qm_volume_equations_pnw_updated_091914.pdf
// Equation 1: western Oregon and Washington (Brackett 1973)
FiaCode.PseudotsugaMenziesii => - 3.21809F + 0.04948F * logHeightInFeet * logDbhInInches - 0.15664F * logDbhInInches * logDbhInInches +
2.02132F * logDbhInInches + 1.63408F * logHeightInFeet - 0.16184F * logHeightInFeet * logHeightInFeet,
// FIA Equation 6: all of Oregon and California (Chambers 1979)
FiaCode.TsugaHeterophylla => - 2.72170F + 2.00857F * logDbhInInches + 1.08620F * logHeightInFeet - 0.00568F * dbhInInches,
_ => throw Trees.CreateUnhandledSpeciesException(trees.Species)
};
return(MathV.Exp10(cvtsl));
}
/// <summary>
/// Get cubic volume to a 10 centimeter (four inch) top.
/// </summary>
/// <param name="trees">Trees in stand.</param>
/// <param name="treeIndex">Tree.</param>
/// <returns>Tree's volume in m³.</returns>
public static float GetMerchantableCubicFeet(Trees trees, int treeIndex)
{
if (trees.Units != Units.English)
{
throw new NotSupportedException();
}
float dbhInInches = trees.Dbh[treeIndex];
if (dbhInInches < Constant.InchesPerCentimeter * Constant.Bucking.MinimumScalingDiameter4Saw)
{
// CV4 regression goes negative, unsurprisingly, for trees less than four inches in diameter
return(0.0F);
}
float cvts = FiaVolume.GetCubicFeet(trees, treeIndex);
if (cvts <= 0.0)
{
return(0.0F);
}
float basalAreaInSquareFeet = Constant.ForestersEnglish * dbhInInches * dbhInInches;
float tarif = trees.Species switch
{
// Waddell K, Campbell K, Kuegler O, Christensen G. 2014. FIA Volume Equation documentation updated on 9-19-2014:
// Volume estimation for PNW Databases NIMS and FIADB. https://ww3.arb.ca.gov/cc/capandtrade/offsets/copupdatereferences/qm_volume_equations_pnw_updated_091914.pdf
// Douglas-fir and western hemlock use the same tarif and CV4 regressions
// FIA Equation 1: western Oregon and Washington (Brackett 1973)
// FIA Equation 6: all of Oregon and California (Chambers 1979)
FiaCode.PseudotsugaMenziesii or
FiaCode.TsugaHeterophylla =>
0.912733F *cvts / (1.033F * (1.0F + 1.382937F * MathV.Exp(-4.015292F * dbhInInches / 10.0F)) * (basalAreaInSquareFeet + 0.087266F) - 0.174533F),
_ => throw Trees.CreateUnhandledSpeciesException(trees.Species)
};
return(tarif * (basalAreaInSquareFeet - 0.087266F) / 0.912733F);
}
/// <summary>
/// Get Scribner board foot volume for 32 foot logs to a six inch top.
/// </summary>
/// <param name="trees">Trees in stand.</param>
/// <param name="treeIndex">Tree.</param>
/// <returns>Tree's volume in Scribner board feet</returns>
public static float GetScribnerBoardFeet(Trees trees, int treeIndex)
{
if (trees.Units != Units.English)
{
throw new NotSupportedException();
}
// repeat code of GetCubicFeet() as this provides about a 6% speedup
float dbhInInches = trees.Dbh[treeIndex];
if (dbhInInches < 6.0F)
{
return(0.0F);
}
float logDbhInInches = MathV.Log10(dbhInInches);
float heightInFeet = trees.Height[treeIndex];
float logHeightInFeet = MathV.Log10(heightInFeet);
float cvtsl = trees.Species switch
{
// Waddell K, Campbell K, Kuegler O, Christensen G. 2014. FIA Volume Equation documentation updated on 9-19-2014:
// Volume estimation for PNW Databases NIMS and FIADB. https://ww3.arb.ca.gov/cc/capandtrade/offsets/copupdatereferences/qm_volume_equations_pnw_updated_091914.pdf
// Equation 1: western Oregon and Washington (Brackett 1973)
FiaCode.PseudotsugaMenziesii => - 3.21809F + 0.04948F * logHeightInFeet * logDbhInInches - 0.15664F * logDbhInInches * logDbhInInches +
2.02132F * logDbhInInches + 1.63408F * logHeightInFeet - 0.16184F * logHeightInFeet * logHeightInFeet,
// FIA Equation 6: all of Oregon and California (Chambers 1979)
FiaCode.TsugaHeterophylla => - 2.72170F + 2.00857F * logDbhInInches + 1.08620F * logHeightInFeet - 0.00568F * dbhInInches,
_ => throw Trees.CreateUnhandledSpeciesException(trees.Species)
};
float cubicFeet = MathV.Exp10(cvtsl);
float basalAreaInSquareFeet = Constant.ForestersEnglish * dbhInInches * dbhInInches;
float tarif = trees.Species switch
{
// Waddell K, Campbell K, Kuegler O, Christensen G. 2014. FIA Volume Equation documentation updated on 9-19-2014:
// Volume estimation for PNW Databases NIMS and FIADB. https://ww3.arb.ca.gov/cc/capandtrade/offsets/copupdatereferences/qm_volume_equations_pnw_updated_091914.pdf
// Douglas-fir and western hemlock use the same tarif and CV4 regressions
// FIA Equation 1: western Oregon and Washington (Brackett 1973)
// FIA Equation 6: all of Oregon and California (Chambers 1979)
FiaCode.PseudotsugaMenziesii or
FiaCode.TsugaHeterophylla =>
0.912733F *cubicFeet / (1.033F * (1.0F + 1.382937F * MathV.Exp(-4.015292F * dbhInInches / 10.0F)) * (basalAreaInSquareFeet + 0.087266F) - 0.174533F),
_ => throw Trees.CreateUnhandledSpeciesException(trees.Species)
};
float cv4 = tarif * (basalAreaInSquareFeet - 0.087266F) / 0.912733F;
// conversion to Scribner volumes for 32 foot trees
// Waddell 2014:32
// float rc6 = 0.993F * (1.0F - MathF.Pow(0.62F, dbhInInches - 6.0F));
float rc6 = 0.993F * (1.0F - MathV.Exp(-0.6896598794F * (dbhInInches - 6.0F))); // log2(0.62) = -0.6896598794
float cv6 = rc6 * cv4;
float b4 = tarif / 0.912733F;
float logB4 = MathV.Log10(b4);
// float rs616 = MathF.Pow(10.0F, 0.174439F + 0.117594F * logDbhInInches * logB4 - 8.210585F / (dbhInInches * dbhInInches) + 0.236693F * logB4 - 0.00001345F * b4 * b4 - 0.00001937F * dbhInInches * dbhInInches);
float rs616 = MathV.Exp10(0.174439F + 0.117594F * logDbhInInches * logB4 - 8.210585F / (dbhInInches * dbhInInches) + 0.236693F * logB4 - 0.00001345F * b4 * b4 - 0.00001937F * dbhInInches * dbhInInches);
float sv616 = rs616 * cv6; // Scribner board foot volume to a 6 inch top for 16 foot logs
float rs632 = 1.001491F - 6.924097F / tarif + 0.00001351F * dbhInInches * dbhInInches;
float sv632 = rs632 * sv616; // Scribner board foot volume to a 6 inch top for 32 foot logs
Debug.Assert(rc6 >= 0.0F);
Debug.Assert(rc6 <= 1.0F);
Debug.Assert(rs616 >= 1.0F);
Debug.Assert(rs616 <= 6.8F);
Debug.Assert(rs632 >= 0.0F);
Debug.Assert(rs632 <= 1.0F);
Debug.Assert(sv632 >= 0.0F);
Debug.Assert(sv632 <= 10.0 * 1000.0F);
return(sv632);
}
}
}
