This makes for an interesting tree risk assessment case study.

An ISA TRAQ, QTRA, and VALID tree risk assessment were carried out on the same Pine trees in Western Springs, Auckland | NZ.

It involves around 200 Pinus radiata. From a risk of branch or tree failure perspective, the trees of particular interest are those that could fall onto a footpath or property.

The reports are linked.

ISA TRAQ | August 2019 

Risk Ratings
1 Extreme
1 High-Extreme
7 High
1 Medium-High
36 Medium
23 Low-Medium
148 Low

QTRA | December 2019

Risk of Harm for 15 trees of most concern
4 1/30,000
7 1/300,000
1 1/500,000
2 <1/1,000,000

Random tree part or tree onto footpath
1/400,000 (Size Range 4)
1/500,000 (Size Range 3)
1/1,000,000 (Size Range 2)
<1/1,000,000 (Size Range1)

VALID Report | October 2020
VALID Data

Risk
1 Not Acceptable
50 Not Tolerable
6 Tolerable
141 Acceptable