ets energex brief supplementary report nvl12a pink blood ... 2 ets...ets energex brief supplementary...

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ETS Environmental Services Ref: senior consulting arborist Cassian Humphreys [email protected] ETS Energex brief supplementary report NVL12A Pink Blood Wood scheduled for monitoring/crown works -

inspected - 24/11/11 Report 4/12/11 - feeder assessed and report proof read by ETS arborist Jonathan Cowan

ETS Energex Brief Supplementary Report NVL12A

Pink Blood Wood scheduled for monitoring &

crown works

Noosa Heads 4/12/11

By Cassian Humphreys

ETS Environmental Services

Inspected - 24/11/11

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ETS State Manager – Gary Wedel 53 Cordwell Road, Yandina QLD 4561 – Ph 07 54547400 ETS Business Manager (Environmental) – Nick Cook, Yandina QLD 4561 – Ph 07 54547400 Mobile phone Cassian – 0427685424 ABN - 77640068488

Cassian Humphreys ETS Environmental ServicesCassian Humphreys ETS Environmental ServicesCassian Humphreys ETS Environmental ServicesCassian Humphreys ETS Environmental Services Senior Arboricultural ConsultantSenior Arboricultural ConsultantSenior Arboricultural ConsultantSenior Arboricultural Consultant

Complete Professional Indemnity & Public Liability Insurance. Corporate membership of The International Society of Arboriculture - Australian Chapter. Qualified & experienced contractually & as a consultant – City & Guilds 1&2 (Hort), Nch-Hort (UK), Nch-Hort (Arb)/Merrist Wood UK (equivalent of Cert 4Arb- AQF). Australian Diploma in Arboriculture (AQF-5). Trainer & Assessor (AQF-4) Author -The Tree Culture Course - theory course for tree managers. Founder of the VTA Program for ETS Tree Mechanics Inspector – Hazard/Risk assessor of trees QTRA licence 1372.

15/12/11

John Bevelander

Energex Metro South

Contracts Vegetation

Visual Tree Assessment Officer Phone: 3407 6658 Mobile: 0448 188 091 Fax: 3000 8888 Email: [email protected]

Table of Contents

• 1.0: Page 3 - Summary – NVL12A Noosaville Pink Bloodwood

• 2.0: Page 3 - 6 Report/Discussion/Recommendations

• 3.0: Page 7 - Conclusion

• 4.0: Page 8 - Background & Methodology for ETS ES Consultancies

(Note – being a brief report the report, discussion and recommendations are all part of

the same chapter)

For consultancy, educational service, & arboricultural operations

Email - [email protected]

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1.0: Summary

The small Noosaville Feeder NVL12A was appraised by arborist Jonathan Cowan (21

11/11). In the course of general VTA inspection works observations were recorded (both

on spread sheet and further developed in this report) on a Pink Blood Wood.

This is a category A Feeder covering Noosa Heads and Noosaville. The tree with

significant VTA symptoms is located on Strip map 3 between poles P51979 & P51978 (on

the junction of Arkana Drive and Leslie Drive). The Blood Wood is located in the

grounds of a private property at Noosa Heads.

The Gum a veteran tree (storm damage and lightning strike), with a major decay cavity

at the base of a co-dominant limb with epicormic/endocormic characteristics.

Due to the sensitive parameters concerning this tree, potential risk to HV, its value to

local environment and its custodians, with Energex approval this report was drafted.

Pink blood wood and location at Noosa Heads

2.0: Report, discussion & recommendations Veteran trees such as this Noosa Heads Pink Blood Wood - Corymbia intermedia are

generally rare on the Energex network.

The tree with an approximate crown height of 16m and approximate crown spread of

10m has a DBH (Diameter at Breast Height) of 95cm (very large for a coastal gum –

coastal trees tend to be `bonsai-ed’ by the coastal environment) . This specimen is of

good vitality (as evidenced by bark/foliage colour and leaf size typical to the species in

good health). Its vitality is attributed to a large footprint of a forest type ecosystem

throughout the majority of its root zone. Also because the gum is in sand (trees subject

to hard landscape growing in sandy soils tend to better adapt due to a higher level of

resistance to soil compaction).

This tree located beside P51979 has in the past been subject to storm damage and a

lightning strike injury.

Summary –

N

South-eastern side

Fig: 1 Google images

Overall the tree has a reasonable height over diameter (H/D) bar the limb (replacement

leader) in question (see Fig: 2). This is caused by a diminished wall thickness at its

attachment point due to a decay cavity at its base and its structural nature as a limb

grown from a dormant bud (in transition from epicormic to endocormic) following past

crown failure.

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The Pink Blood wood – located between P51979 & P51978

North-eastern side side

Fig: 2 Fig: 3

Report continued–

Portion of

trees crown

of concern to

HV

Due to

mechanical

constraint at

point of

attachment

Fig: 4 Fig: 5 Fig: 6

Both Jonathan Cowan and Cassian Humphreys appraised the mechanically constrained limb (tree

climbing assessment) – see Fig: 4. Using VTA as well as sounding the limb with an acoustic hammer

(Thor 710). Concerns lie with the attachment point with respect to wall thickness and the end load

weight/lever arm of the replacement leader (H/D). Added concern with this leader relates to the past

lightning strike damage and a lack of visible reactive growth in the form of tension wood on the

tension side of the replacement limb/leader.

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Relating to Figs: 5 to 6 the outside of the decay cavity extends from (approximately) 5m

from ground level to the old tension failure (ref: dotted line Fig 4), though internally the

cavity is expected to extend into the trees root plate at ground level.

Following closer inspection of the lighting damage and conversation with the land

owner it is interesting to note that the lighting blast connected with the trees central

upper crown killing the leader (dead upper leader visible in aerial image Fig: 1).

Fortunately for the gum the lightning was channeled into the ground through a

neighboring Cocus palm. As a result the palm was killed and the gum was saved from a

blast injury down its trunk to ground level, the blast was reported to have occurred 3-4

years ago.

Based on the nature of advanced age trees to shed elongated limbs and the VTA on this

tree retrenchment pruning is recommended. Normally we would recommend a crown

reduction to growth points as with AS 4373 2007. However in the case of the

morphology of the leader in question suitable growth points do not exist. To reduce this

crown to standard would compromise the health of the tree by removing too much

crown material with stored energy reserves (carbohydrate). Also standard reduction

pruning to cut to lower growth points will remove a large volume of crown with

dormant buds. Dormant buds high in a trees crown are in locations where shooting

growth may better occlude retrenchment cuts.

Considering tree longevity it is better to have small pruning wounds and a large surface

area disposed for shoot production rather than large pruning wounds and a smaller

surface area for shoot production. Also with respect to epicormic shoots generated from

limbs cut high in a trees crown the transition from epicormic to endocormic (via

incremental growth) can be expected to occur more rapidly.

Retrenchment pruning (as pioneered with UK arboriculture – Neville Fay & Paul Muir –

UK Treework Environmental Practice) involves the shortening of lever arms high in the

trees crown as a means to preserve lower crown structure (usually carried out in

association with coronet cuts). This practice prevents branch breakout/tension failure

lower in the crown which significantly reduces tree lifespan and incurs greater risk. This

also encourages the tree to develop epicormic limbs lower in its crown to assist with

energy production.

Relating to a study I am making in association with USA Arborist Guy Meilleur on

storm damage effects on tree crowns that have transitioned from epicormic to

endocormic, we have a number of records which support crown retrenchment above

mechanically constrained crown structure.

These involve crown tension failures above epi/endo branch unions at zones of

elongation commonly referred to as hot spots. Our own (ETS/Energex) findings with the

Gap storm (08) support that epi/endo limb failure often fails at hotspots above branch

unions rather than at branch unions.

Report continued–

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Essentially what is recommended with the Pink Blood Wood tree is crown retrenchment

by hand as a means to reduce likelihood of electrical outage by crown failure at the

branch union. Though in this case it is not commercially practical to carry out coronet

cuts (based on time frame and current utility work standards) I propose we mimic the

natural storm retrenchment process (by shortening elongated limbs) as a means to retain

and risk manage potentially defective crown structure. Whilst better retaining tree

health (via crown retention over crown removal).

As is recorded on spread sheet we advise monitoring of this tree with a return

assessment in five years 24/11/16. Follow up crown works is to be expected and

considered following the trees growth response.

Note – The gum is a habitat tree to a range of nesting birds, with Parrots and Koala’s

having been observed over a period of years. Currently the tree is maintained by

Sunshine Coast Arborist Dan Law of Sunshine Tree Surgery.

Report continued–

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3.0: Conclusion

In conclusion the Pink Blood Wood gum a significant habitat tree with veteran

characteristics due to its environment has reached a stage in its growth cycle where

likelihood of limb failure is apparent based on its age, body language and history.

Loss of major crown structure however is easily preventable by shortening major lever

arms, either by crown reduction pruning or by retrenchment pruning.

For the sake of retaining the tree as long as practically possible (in support of the wild

life it supports) it is recommended that pruning works be carried out that best favour

the trees long term health. Two major limbs have been identified as being most likely to

fail in the recent future, only one is likely to impact on HV.

The limb leaning into HV cannot successfully have lever arms reduced by crown

reduction pruning without causing serious stress to that limb and corresponding

portions of the trees crown. Therefore crown retrenchment pruning is recommended.

In the history of the ETS/Energex VTA Program this is the first veteran tree found

(potentially impacting on HV) that in the interests of its longevity is to be best risk

managed by retrenchment pruning.

Because of the unusual nature of the gum (relating to HV) and as it is not a live line tree

it is recommended that one of the ETS Arborists carry out the work, Jonathan Cowan,

Will Clegg or I. Based on the crown structure to be pruned we recommend the use of

hand saws over the use of chainsaws.

From this time onward with Energex approval it is recommended that retrenchment

pruning be a practice we incorporate into the program for ancient and veteran trees.

With consideration of epicormic verses endocormic crown structure in trees general

global arboricultural opinion separates epicormic from endocormic growth. With

epicormic growth as being regarded bad (due to the incidence of branch break out) and

endocormic growth being good. In reality there is no separation between epicormic

verses endocormic crown structure, just fewer growth increments and wood rays

binding/connecting epicormic limbs to stems. The transition from epicormic to

endocormic morphology is governed by time tree vitality and growth.

Based on lessons learned on the VTA Program (since 2007) and combined experience

(ETS/Energex) of large populations of gums covering the Energex network epicormic

limb failure (at point of attachment) is a rare occurrence, usually occurring on limbs with

a diameter of no more than 15mm. From the point of view of risk management of trees

with epicormic crowns a standard VTA inspection of attachment points is considered to

be effective. The need for the management of epicormic crowns is in ETS/Energex

experience not always necessary and as with the Pink Blood Wood if needed can be

achieved by a light reduction of lever arm.

Thank you for your attention,

Best regards Cassian Humphreys.

Conclusion –

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4.0 Background and Methodology for ETS ES Consultancies

The systems/publications for biochemical & biomechanical appraisal (for hazard assessment, risk reduction and tree longevity) we utilise are:

- VTA (Visual Tree Assessment – Prof. Dr. Claus Mattheck 1994) based on ‘The body Language of Trees’. According to VTA the most successful tree is a tree with a chain of links (leaders, branches, trunk collars, trunk, roots etc) each matched equally to the load. VTA is a means to observe, quantify, and record biomechanical constraints and signs of optimisation in trees. Cassian Humphreys has been developing the ETS VTA Tree Assessment Program since 2005.

- QTRA (Quantified Tree Risk Assessment) applies established and accepted risk management principles to tree safety management. This system involves calculation and quantification of target, impact potential, (size) and probability of failure. Values derived from the assessment of these components are used to calculate the probability of significant harm occurring.

- An Evaluation of Hazard Trees (ISA – Matheny & Clark 1994). - Modern Arboriculture and a New Tree Biology by Dr Alex Shigo. - Plants in Action by Atwell, Kriedmann & Turnbull (Australian Botanists) - Soil Analysis an Interpretation Manual (ASPAC - The Australian Soil & Plant

Analysis Council – CSIRO publication) editors Peverill, Sparrow & Reuter. - The Soil Food Web – President and founder Dr Elaine Ingham - Practical Conservation Biology by Lindenmayer & Burgman – for sustainable

land management practice. - References to pruning are taken from the Tree Care Division Target Pruning

Manual and are based on AS 4373 – 2007. - The ETS tree care protocol is based on the ETS Tree Care Management System. - Note in the case of mature trees my VTA assessment involves aerial inspection

based on the understanding that it is not always possible to appraise mature trees from the ground.

The tools we use are: - A Lumix Panasonic with *14 zoom (10 Mega pixels) for photographic

documentation. - A diameter measuring tape which gives an average diameter based on the

circumference measurement; measurements are taken from breast height (DBH). - The Sunto Clinometer, to accurately measure tree height. - The H/D (height over diameter) measurement tool to gauge stem taper or

slenderness (Mattheck), the H/D ratio is based on the Mitchell - Formula. - The Thor 10 Sounding Hammer for assessing wood resonance. - A 5mm diameter 480mm Haglof Increment Borer for core sampling - Thermal Imaging Camera – Thermal Imaging Camera – Thermal Imaging is

currently the most effective technology to support VTA and allows assessment of functional wood present in relation to non-functional or dysfunctional wood. Particularly useful in picking up on mechanical constraint prior to it becoming visual externally. TIC technology associated with the appropriate software is the next evolutionary step in understanding and quantifying the bio-mechanical status of trees.

Where necessary we may recommend the use of such technology (TIC, Resistograph, Air spade, TTA, Ground Penetrating Radar etc) as a means to provide the highest level of service to our clients and the trees we work for.

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