## Wood Density in weight per cubic dimension

determine the weight of a cubic unit of wood given secific gravity & moisture content.

$$\rho_x = \rho_w G_x \left( 1 + x / 100 \right)$$

where $\rho_x$ is the wood densityn the same units as the water density, $\rho_w$ is the water density in the units of interest, $G_x$ is the specific gravity at a specified moisture content, and $x$ is the desired output moisture content. The equation from Wood Handbook Chapter 4, page 10-12, General Technical Report FPL-GTR 190.

"Specific gravity $G_x$ is defined as the ratio of the density of a substance to the density of water $\rho_w$ at a specified reference temperature, typically 4° C (39° F), where $\rho_w$ is 1.000 g cm-3 (1,000 kg m-3 or 62.43 lb ft-3)." (Wood Handbook)

### Example

Imperial Units
sg or $\rho_x$ = 0.4
mc or $x$ = 12.0
wdensity of $\rho_w$ = 62.43 cf ft-3 or 1000 kg m-3
Answer = 27.968 lb. ft-3 or 448 kg m-3

### Code

#### Visual Basic

 
Function density(specificgravity As Single, Optional moisturecontent As Single = 12#, Optional waterdensity As Single = 62.43)
' Function to calculate the density of a cubic unit of wood.
' waterdensity must in in the unit desired for output.
' by David R. Larsen, Copyright June 2, 2015
' Creative Commons http://creativecommons.org/licenses/by-nc/3.0/us/
'
' "Specific gravity G  is defined as the ratio of the density of a substance
' to the density of water pw at a specified reference temperature, typically
' 4 C (39 F), where pw  is 1.000 g cm-3(1,000 kg m-3 or 62.43 lb ft-3)." (Wood Handbook)
' Equation from Wood Handbook Chapter 4, page 10-12,  General Technical Report FPL-GTR 190

density = waterdensity * specificgravity * (1 + (moisturecontent / 100#))

End Function

Excel® Visual Basic Code

#### R Statistical Package Code

 
density=function( sg, mc=12.0, waterdensity=62.43 )
{
# Function to calculate the density of a cubic unit of wood.
# waterdensity must in in the unit desired for output.
# by David R. Larsen, Copyright June 2, 2015
# Creative Commons http://creativecommons.org/licenses/by-nc/3.0/us/
#
# "Specific gravity G  is defined as the ratio of the density of a substance
# to the density of water pw at a specified reference temperature, typically
# 4 C (39 F), where pw  is 1.000 g cm-3(1,000 kg m-3 or 62.43 lb ft-3)." (Wood Handbook)
# Equation from Wood Handbook Chapter 4, page 10-12,  General Technical Report FPL-GTR 190

density = waterdensity * sg * (1 + (mc / 100.0))
density

}

R Statistical Package Code

#### Python Code

 
#!/usr/local/bin/python
# Function to calculate the density of a cubic unit of wood.
# waterdensity must in in the unit desired for output.
# by David R. Larsen, Copyright June 2, 2015
# Creative Commons http://creativecommons.org/licenses/by-nc/3.0/us/
#
# "Specific gravity G  is defined as the ratio of the density of a substance
# to the density of water pw at a specified reference temperature, typically
# 4 C (39 F), where pw  is 1.000 g cm-3(1,000 kg m-3 or 62.43 lb ft-3)." (Wood Handbook)
# Equation from Wood Handbook Chapter 4, page 10-12,  General Technical Report FPL-GTR 190

def density( sg, mc=12.0, waterdensity=62.43):
density = waterdensity * sg * (1 + (mc / 100.0))
return density

print "imperial =", density( 0.4 )
print "imperial =", density( 0.4, 12.0, 62.43)
print "si =", density( 0.4, 12.0, 1000.0)

Python Code

Note the python file has a extra "txt" at the end to allow the files to be viewed in a web browser.

#### Go Code

 
// Function to calculate the density of a cubic unit of wood.
// waterdensity must in in the unit desired for output.
// by David R. Larsen, Copyright June 2, 2015
// Creative Commons http://creativecommons.org/licenses/by-nc/3.0/us/
//
// "Specific gravity G  is defined as the ratio of the density of a substance
// to the density of water pw at a specified reference temperature, typically
// 4 C (39 F), where pw  is 1.000 g cm-3(1,000 kg m-3 or 62.43 lb ft-3)." (Wood Handbook)
// Equation from Wood Handbook Chapter 4, page 10-12,  General Technical Report FPL-GTR 190
package main

import (
"fmt"
)

func density(sg float64, mc float64, wdensity float64) float64 {
density := wdensity * sg * (1 + (mc / 100.0))
return density
}

func main() {
fmt.Println("imperial =", density(0.4, 12.0, 62.43))
fmt.Println("si =", density(0.4, 12.0, 1000.0))
}

Run code in the Go Playground
Go Code

Note the Go file has a extra "txt" at the end to allow the files to be viewed in a web browser.

This work is licensed under a Creative Commons Attribution-Noncommercial 3.0 United States License.

Author: Dr. David R. Larsen, Copyright 2012
Created: June 2, 2015
Last Updated: June 2, 2015