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Tree Appraisal Calculations

The following are the calculations for tree appraisal

These calcs are performed on the save of the inspection:

  • If the required data is missing don't calculate
  • Some values that get calculated are temporary values only used in determining other values. They do not display in a field that is visible to the user. Those are noted below.

Diameter (D) <--> Circumference (C)

  • In the Tree: Inspection, if Diameter is entered calculate the Circumference
    • C= Pi * D
  • In the Tree: Inspection, if Circumference is entered calculate the diameter
    • D = C / Pi
  • If a value is entered in both the Circumference and Diameter (thru REST API) the diameter will be used to calculate the circumference
  • If either a Diameter or Circumference is entered, the other is calculated appropriately. Diameter takes priority over Circumference. If the user enters a Circumference and then enters a conflicting Diameter, the Circumference will be recalculated to match the Diameter.
  • The Unit Type field is protected on the UI for both the Circumference and Diameter.  The Unit Type for the Replacement Tree size in the Tree Library is used to determine if the circumference and diameter should be set to 'in' or 'cm'.   If no scientific name is entered for the tree or the library does not have a replacement tree size - default to 'in'

Trunk Area (TA) 

Calculated value. Read only field in the inspection

  • Requires tree Diameter
  • TA = (Pi /4) * D2
  • Shows in the UI as soon as Diameter is populated.
  • Unit Type will be set to the squared version of the Diameter unit type.

Adjusted Trunk Area (ATA)

Temporary value - not stored

  • Requires tree Diameter
  • If Diameter > 30 in (75 cm) use ATA
  • ATA =  (-0.335 * D2) + (69.3 * D) - 1087
  • Else use Trunk Area (TA)

Replacement Tree Size Area (RTSA) 

  • Requires Tree Library field - Replacement Tree Size (RTS)
    • RTSA = (Pi /4) * RTS2

Appraised Tree Size Increase (ATSI)

Temporary value - not stored

  • If Tree diameter > Replacement Tree Size 
    • ATSI = Trunk Area - Replacement Tree Size Area
  • Else 
    • ATSI = Trunk Area

Basic Tree Cost (BTC)

Temporary value - not stored

  • Requires two values from Tree Library
    • Unit Tree Cost (UTC) - show in inspection based on Scientific Name from Tree Library
    • Installed Tree Cost (ITC) - show in inspection based on Scientific Name from Tree Library
  • BTC = (ATSI * UTC) + ITC

Location Rating (LR)

  • Requires values in fields on Tree: Inspection:
    • Site (S)
    • Contribution (C)
    • Placement (P)
  • LR = (S + C + P) / 3
  • This calc needs to show in the UI when all required values are entered
    • Verify when fields do not contain values

Condition Rating (CR)

  • Requires values in 8 fields on Tree: Inspection:
    • Roots = 2 fields - Roots Health and Roots Structure
    • Trunk = 2 fields - Trunk Health and Trunk Structure
    • Scaffold = 2 fields - Scaffold Branches Health and Scaffold Branch Structure
    • Small Branches = 1 field - Small Branches and Twig Health
  • Foliage = 1 field - Foliage and Bud Health
  • This calculation works when all required values are entered
    • If one or more fields are blank, the value does not calculate
    • Verify follows validation rules for individual fields
  • CR = ((Roots + Trunk + Scaffold + Small Branches + Foliage) / 32) * 100

Determine Appraisal Method

  • Compare the entered Diameter to the value Replacement Tree Size (Tree Library)
  • If the Diameter is > Replacement Tree Size
    • set the Appraisal method to Trunk Formula
    • perform the calculation below
  • Else we are using Replacement Cost

Appraised Value (AV)

  • Requires:
    • Basic Tree Cost (BTC) - calculated, temporary value - see above on how calculated
    • Species Rating (SR) - show in inspection based on Scientific Name from Tree Library
    • Condition Rating (CR) - calculated and shown in Tree: Inspection
    • Location Rating (LR) - calculated and shown in Tree: Inspection
    • Installed Cost (IC) - show in inspection based on Scientific Name from Tree Library
  • If Appraisal Method is 'Trunk Formula'
    • AV =  ((SR/100) * (CR/100) * (LR/100))  * BTC   
  • If Appraisal Method is 'Replacement Cost'
    • AV = (IC * (SR/100) * (CR/100) * (LR/100))  + RCC

Adjusted Installed Plant Cost (AIPC)

  • Requires all of these values or AIPC will not be calculated:
    • Species Rating (SR) - show in inspection based on Scientific Name from Tree Library
    • Condition Rating (CR) - calculated and shown in Tree: Inspection
    • Location Rating (LR) - calculated and shown in Tree: Inspection
    • Installed Cost (IC) - show in inspection based on Scientific Name from Tree Library
  • AIPC = (IC * SR * CR * LR) 
    OPTIONAL 
    • Removal and Cleanup Costs (RCC) - field on Tree: Inspection

Adjusted Appraised Value (AV)

  • Tree Diameter is over 30 inches
  • If Appraisal Method is 'Trunk Formula'
    • AV = AIPC + RCC    [or another way to look at it is:  AIPC = ((SR/100) * (CR/100) * (LR/100))  * BTC  ]   
  • If Appraisal Method is 'Replacement Cost'
    • AV = AIPC + RCC    [or another way to look at it is:  AIPC = (IC * (SR/100) * (CR/100) * (LR/100))  + RCC  ]

 

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