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37 Formulas

Log Measurement Formulas

Log rules and round-timber volume equations.

Scribner Log Rule

Open the Scribner Log Rule →
Scribner Log Rule
Scribner = (0.79 x D^2 - 2 x D - 4) x (L / 16) BF, D=in DIB, L=ft
Used in Scribner Log Rule
Scribner Log Rule
Decimal C = floor(BF / 10) x 10 official USFS rounded form
Used in Scribner Log Rule

Doyle Log Rule

Open the Doyle Log Rule →
Doyle
BF = ((D - 4)^2 / 16) x L D = DIB inches, L = length feet
Used in Doyle Log Rule
Scribner
BF = (0.79 x D^2 - 2xD - 4) x (L/16)
Used in Doyle Log Rule
International
BF = (0.905 x (D/2)^2 - D) x (L/16)
Used in Doyle Log Rule
IS 1902 India
V = pi x (D/200)^2 x L m3, D in cm, L in m
Used in Doyle Log Rule
Conversion
1 m3 = 423.78 BF | 1 BF = 2359 cm3
Used in Doyle Log Rule

Huber Formula

Open the Huber Formula →
Huber
V = A_mid x L = pi x (D_mid/200)^2 x L D in cm, L in m
Used in Huber Formula
Weight
W = V x density (kg/m3)
Used in Huber Formula
Hoppus feet
Hft = V / 0.02832
Used in Huber Formula

Sawdust Waste Estimator

Open the Sawdust Waste Estimator →
Sawdust Waste Estimator
Boards per pass = floor(D_cm x 10 / (thickness_mm + kerf_mm))
Used in Sawdust Waste Estimator
Sawdust Waste Estimator
Kerf loss % = kerf_mm / (thickness_mm + kerf_mm) x 100
Used in Sawdust Waste Estimator
Sawdust Waste Estimator
Slab waste approx = (1 - pi/4) x log_volume = 21.5%
Used in Sawdust Waste Estimator
Sawdust Waste Estimator
LRF = lumber_volume / log_volume x 100
Used in Sawdust Waste Estimator

Bark Deduction Tool

Open the Bark Deduction Tool →
Bark Deduction Tool
Bark thickness each side = OB_diameter x bark_factor / 200
Used in Bark Deduction Tool
Bark Deduction Tool
UB diameter = OB diameter - 2 x bark_thickness
Used in Bark Deduction Tool
Bark Deduction Tool
Volume OB = pi x (D_OB_mid / 200)^2 x L (Huber method)
Used in Bark Deduction Tool
Bark Deduction Tool
Volume UB = pi x (D_UB_mid / 200)^2 x L
Used in Bark Deduction Tool
Bark Deduction Tool
Bark volume % = (V_OB - V_UB) / V_OB x 100
Used in Bark Deduction Tool

Hoppus Calculator

Open the Hoppus Calculator →
Hoppus Calculator
Hoppus Feet = (G/4)^2 x L / 144 G = girth inches, L = length feet
Used in Hoppus Calculator
Hoppus Calculator
Hoppus Metre = (G/4)^2 x L / 10000 G = girth cm, L = length metres
Used in Hoppus Calculator
Hoppus Calculator
True volume = Hoppus x (4/pi) = Hoppus x 1.2732
Used in Hoppus Calculator
Hoppus Calculator
1 Hoppus foot = 0.02832 m3 | 1 BF = 2359 cm3
Used in Hoppus Calculator

Standing Tree Volume

Open the Standing Tree Volume →
IS 4213 India
V = (pi/4) x DBH^2 x H x f DBH in metres, H in metres
Used in Standing Tree Volume
Basal Area
BA = pi x (DBH/200)^2 m2, DBH in cm
Used in Standing Tree Volume
Standing Tree Volume
QS boards per quarter = floor(R x 10 / (thickness + kerf))
Used in Standing Tree Volume

Smalian Formula

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Smalian
V = ((A1 + A2) / 2) x L A = pi x (D/200)^2 D in cm, L in m
Used in Smalian Formula
Huber
V = A_mid x L A_mid at midpoint
Used in Smalian Formula
Newton
V = (A1 + 4 x A_mid + A2) / 6 x L most accurate
Used in Smalian Formula

International Log Rule

Open the International Log Rule →
Per 8-ft section
BF = (0.905 x (D_s/2)^2 - D_s) x (L_s/16)
Used in International Log Rule
International Log Rule
D_s = diameter at each 8-ft section (adjusted for taper)
Used in International Log Rule
International Log Rule
Full log = sum of all 8-ft sections
Used in International Log Rule

Log Taper Calculator

Open the Log Taper Calculator →
Log Taper Calculator
Taper = (D_large - D_small) / L cm per metre
Used in Log Taper Calculator
Log Taper Calculator
Form factor f = V_huber / V_cylinder
Used in Log Taper Calculator
IS 1902 Class 1
taper <= 0.5 cm/m (slight)
Used in Log Taper Calculator
IS 1902 Class 2
0.5 to 1.5 cm/m (moderate)
Used in Log Taper Calculator
IS 1902 Class 3
> 1.5 cm/m (excessive)
Used in Log Taper Calculator