A Billion Dollars of Value

Utilising:

  • the canopy value from the Minimum Industry Standard MIS506, Appendix 3 of $54.56 per square metre; and 
  • the estimated average canopy increase from the reduced pruning specifications is 7m2 (detail below); and 
  • the number of trees impacted, estimated at 2.5 million (detail below)

 The socio-ecological value is:

$54.46/m2 * 7m2/tree * 2,508,250 trees = $956,195,065 = ~ $1 billion

$54.46/m2 data point reference

Reference:

Appendix 3 of

https://digitalbookstore.trees.org.au/products/MIS506-Tree-Valuation-p586128652

Comment:

The value utilised is conservative compared to valuing individual trees and summing their value losses. Depending on the location, size and importance of an individual tree, the value of canopy per metre squared can be 10 times or more the 54.46/m2 used.

7m2 data point calculation

Figure 1: Canopy area increase achieved allowing for less pruning

Before prune

Prune to recommended

0.3m clearance

Prune to current

1.0m clearance

a. The area is calculated based on the reduced clearance recommendation:

From 1.0m to 0.3m = 0.7m improvement

b. Average tree sizes from Urban Forest management practice:

Trees impacting powerlines are Medium and Large so the average of the two canopy diameters is used:

Average of 8m and 12m = 10m

c. Pruning will vary depending on the size of the tree. On larger trees, a greater area will be impacted. An average area of canopy per tree impacted, “c”, can be expressed simplistically as “a” * “b”:

0.7m * 10m = 7m2

 

2.5 million trees data point calculation

Tree numbers were estimated based on the number of street trees and powerline corridor trees across all Victorian LGA’s. This is based on:

a. The number of LGA’s in LGA’s in Victoria = 79 (Local councils | Victorian Electoral Commission (vec.vic.gov.au))

b. The average number of street trees, private trees and powerline corridor trees per Victorian LGA that will be pruned, irrespective of pruning cycle. The time between pruning cycles is typically 1, 2 or 3 years with some trees not being pruned each cycle, only as required. Private research indicated this number to be 31,750.

c. Therefore, the number of trees impacted by powerline pruning, “c”, is “a” * “b”:

79 LGA’s * 31,750 trees/LGA = 2,508,250 trees

Factors such as clear-to-sky pruning for large trees and whole tree removal, especially around transmission line corridors, and severe pruning which can create hazard trees which also require removal, have not been individually determined.