PiCUS Survey for Christchurch City Council


This report was commissioned by the Parks Unit, Christchurch City Council after an initial inspection to determine the health, and structural condition of the trees was completed. This assessment reviewed the risk of harm to the public using the area where the trees were located and the consequences if the tree(s) were to fail. 


The report concentrated upon four trees requiring Purearb's  assessment to determine the trunk(s) internal structural condition using ultrasound testing. These tests were taken from various heights, using the PiCUS Sonic Tomograph, which measures the velocity of acoustic waves moving through the tree's trunk, calculating the travel time between damaged and good wood in the subject tree(s).   

Timaru Botanical Gardens

Purearb received instruction from Timaru District Council to complete a suitable arboricultural survey and report for the Botanical Gardens, Corner of King & Queen Streets, Timaru. This survey is to determine a comprehensive tree register and condition of trees and incorporates the introduction of protection measures around the trees at the site. Council and residents, for a variety of health, aesthetic, social, economic and environmental reasons regard the Botanical Gardens as an essential and valuable asset in the urban environment. To ensure the longevity of the trees within Timaru Botanical Gardens, Purearb developed a report that provides and promotes sound practical directions in the guidance and assistance in the long-term management of the trees on the site.

Cabling and Bracing of Trees in Timaru 

Purearb received instruction from Timaru District Council to complete an arboricultural inspection and report for the cabling and bracing of the trees in the Timaru district. This assessment is to determined the condition of the restraint and support systems installed, and assessed any adverse deterioration in the supported or supporting structure(s) in the tree(s). Where trees have developed a structural weakness, which presents a hazard to people and property and where the problem cannot be addressed with remedial pruning alone, the installation of restraints and/or supports in the tree, might reduce the risk of structural failure. All forms of restraint in a tree should be installed in accordance with best arboricultural practices, notably demonstrated in the Knowledge of Tree Support Systems in Arboriculture (25400 NZQA), Recommendations for Tree Works (BS 3998: 2010) and Principles of Tree Hazard Assessment and Management (Section 6.5 Lonsdale, D. 2006).


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