Firmwood Deductions

Firmwood Deductions
- What is firmwood?
- Two Methods
  - Gross/ Net Method
  - Net Dimensions (this lecture)
- Ave. Unit Volume (AUV)
  - 'running 1 m volume'
  - ave vol. per metre
    - log: 13R / 17R / 8m
    - vol =
    - AUV (vol/m) =
- Standard Length Deduction Method
  - a) vol. of rot
  - b) AUV
  - c) rot / AUV = length ded'n
  - d) gross length - length ded'n = net length
- Rot Types & Deductions
  - Sap Rot
    - measure sound wood directly
  - Heart Rot
    - Std. Length Ded'n
    - Rad Ded'n
      - 2m half vol = 1m full vol = "area"
      - gross end area - rot end area = net end area
      - convert "net end area" to rads
    - if only one end ...
  - Pocket Rot
    - ~ circular
      - as before
    - ~ rectangular
      - A(rads) * B(rads) * 0.4 = AUV
        
        (A*2) * (B*2) = area cm2
        
        *100 gives vol of 1m "log" in cm3
        
        / 1000 gives AUV (dm3)
        
        2*2*100/1000 = 0.4
      - can use as 'end deduction' ... AUV gross - AUV rot = AUV net
      - can use for L ded'n ... AUV * L(m)=rot vol
    - ~ triangular
      - determine for area of triangle
      - which is half of rectangle
      - ... *by 0.2 (not 0.4)
      - ... A(rads) * B(rads) * 0.2 = AUV
    - we will "pretend" it's a circle
  - Butt Rot
    - Butt Rot == Butt Log
    - Std. Length Method
      - shape is a cone
      - ... but need to know length ...
      - ... which we don't
    - Ratio Method
      - ratio -- ded'n (m)
        
        1/4 -- 0.2 m
        
        1/2 -- 0.4 m
        
        3/4 -- 1.2 m
        
        4/4 -- 2.4 m
      - interpolate if needed
  - Conk/ Knot
    - Length Ded'n
      - 2.4m up + 3.6 m down
      - assume 50% rot
      - if more than 2 conks?
      - if length to end is "too short"?
      - remaining lengths need to be 2.5m for lmbr
  - Missing Wood
    - est. % missing
    - deduct that % off the length
  - Ring Rot
    - Std. Length Method
      - rot vol = vol of rot & core - vol of core
    - Rad Ded'n
      - gross end - outer rot + inner core = net area
      - convert to rads
    - only one end ...