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FRANK RINNINGENIEUR- UND SACHVERSTÄNDIGEN-BÜRO ENGINEERING- AND EXPERT-OFFICE

UNTERSUCHUNG BÄUME, HOLZ, KONSTRUKTIONEN EXAMINATION TREES, TIMBER, CONSTRUCTIONS

ENTWICKLUNG MESSGERÄTE, SOFTWARE DEVELOPMENT MEASUREMENT DEVICES, SOFTWARE

BERATUNG SEMINAR, SCHULUNG, VORTRAG CONSULTATION SEMINARS, TRAINING, LECTURES

E X P E R T R E P O R T

TECHNICAL INSPECTION OF A NORTHERN RED OAK, OLMSTED-FALLS, OHIO, USA

2013 __ / __

FRANK RINN, ÖBVS, DIPL.-PHYS. / VDI REGISTERED TREE EXPERT [email protected]

HARDTSTR. 20-22, 69124 HEIDELBERG, GERMANY TEL (+49) (0)6221 71405-0 FAX -234 WWW.RINNTECH.COM

423 S. 8TH CT., ST. CHARLES, 60174 ILLINOIS, USA TEL (+1)(630)-3772477 FAX-4856133 [email protected]

FRANK RINNTECHNICAL TREE INSPECTION: NORTHERN RED OAK, OLMSTED-FALLS, OH, USA 2013 2 / 18

CONTENTPage

1 Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Contacts, addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3 Inspection and results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4 Summary and conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5 References and further reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16





1 Assignment

Some of the neighbouring trees protecting the oak since decades from wind, are planned to be

removed in the future for developing the area with new buildings. Thus, the wind load may increase

significantly.

Because previous inspections showed that the oak has internal decay, the current extent of these

deteriorations and their impact on stability and safety had to be assessed in more detail in order to

be able to evaluate both current safety level as well as the future perspective of this exceptional tree.

Because of the more than regional importance of this ‘Champion-Tree’, a thorough inspection had to

be carried out using stress-wave (‘sonic’) tomography (ARBOTOM®), root diagnostics

(ARBORADIXTM) and resistance drilling with calibrated, ‘real’ RESISTOGRAPH® devices.

2 Contacts, addresses

Tree Ohio Champion Trees List:

www.ohiodnr.com/forestry/bigtrees/tabid/4810/Default.aspx

Inspection 18. August 2013

Result explained and presented on site

Report 01. September 2013





3 Inspection and results

The first visual impression of the oak explains why it may be listed on a Champion Tree List:





Approximate Crown Sail Area:

Areal picture from GOOGLE: the oak was always

protected from wind coming from West to North

and to North-East (marked green). Since more

than 100 years, a building stood nearby.

Due to the topologic site conditions by building

and surrounding trees, the major wind direction

the oak was facing over the last decades, most

likely was South-East.





Pictures of the main trunk

North: North-East: South-East:

South-West: West: North-West:





Sensor-Positions

Sensor 1 in North: North-East: East:

South-East: South: South:

South-West: West: North-West:





Stress-wave ('sonic') tomogram

The stress-wave (='sonic') tomogram of the stem

base reveals large internal decay areas (red) and

strong/intact outer sections (green).

Referring the section modulus calculation, the

detected and displayed deterioration leads to a

relative loss in load-carrying capacity of this

cross-section of about approximately 40%.

Due to the central location of the deterioration,

this loss is nearly symmetrically distributed for all

wind directions. The green curve indicates that

the tree due to the cross-sectional shape/contour

is best optimized against wind from South-East

and the weakest against wind from West/South-

West. This correlates to the fact that the tree

was always protected against wind from West

but not from South-East.





The ARBORADIXTM diagram reveals lines in a distance of mostly up to 4 or 5m from the trunk (.12

to 15 feet). Interestingly, the lines to East and South-East are green, indicating a higher stress-

wave speed (what is mostly related to better root anchorage). On site, it was indicated after our

inspection that in this area, some 8-10 years ago, there was a soil treatment carried out. Obviously,

this helped the tree to build stronger roots into this direction, what, in addition, helps the tree

physiologically and will, as a consequence, support the stem in responsive growth in order to

compensate for the strength loss due to internal deterioration. The extent and colour of the

Arboradix-lines do not indicate any sign of uprooting danger:





Profiles of (linearily calibratable) resistance drillings at/between sensor positions:

RESISTOGRAPH® profile of a drilling between sensor 2 and 3:

RESISTOGRAPH® profile of a drilling at sensor 11:

RESISTOGRAPH® profile of a drilling at sensor 16:

The average ring width decreases from approximately 6 to approximately 3mm (. 1/10“) within

the last 20 years. The thickness of the remaining intact shell wall (green) ranges between 7 and

14cm (. 3“ to 6“). Decay seems to be progressing outwards on all three inspected spots,

however in different speed (due to the slope from intact to decay: the steeper this slope, the

slower decay progresses, commonly). The central part seems to be hollow (purple).





The stem cross section of the oak suggests that

the current tree developed from several

different trunks or trees, respectively, at least

two or three, probably more. Assuming two

trees as the origin of the present oak, their

radius was approximately 70cm (North) and

80cm (South).

The ring width as visible in the resistance

drilling profiles dropped down from 6mm to

3mm within the last decade.

Following the typical age trend, ring width

stabilizes on a mostly quite constant level when

the tree matures (and does not grow in height

any more).

Because ring-width usually is significantly bigger

in the centre part of cross sections, these age

estimates are rough upper limits. Regarding

size, location, and species of the tree, an age

estimate of about 150 years seems to be

reasonable in this case.

Independently whether the tree developed from

crafted individual trunks or not, the three major

parts of the stem showing intact wood (North,

East, South) seem to be only weakly connected

between each other.

Thus, the existing crown cables are required

and should be maintained in order to keep the

cross section together to bridge the gap of

mechanical connection in the marked areas at

least.





According to tree experts in the area, such trees typically reach 30m (~90feet) at about 50 to 60

years of age. Assuming the tree did not grow significantly in height since age=60y and the tree-

ring width since then (conservatory assumed) stabilized on one average level of approx. 5mm per

year, the trunk gained breaking safety in this time due to increased girth by about 50%: because

the load carrying capacity of a cross section depends on the diameter to the power of three,

every increase of girth by 1% results in an increase of the load carrying capacity by about 3%.

Because wind load mainly depends on tree height, the basic bending safety increases annually as

soon height growth stops.

The APP ArboStApp determines both windload and load carrying capacity of cross sections due to

deteriorations. In addition, ArboStApp calculates the gain in the basic safety factor depending on

the growth rate and time since the tree does not grow in height any more (“Maturity correction”).

For the oak, the tree gained at least about 50% additional safety:

Taking 40% loss in load carrying capacity (due the internal decay) off 150% results in 110% -

meaning that the tree trunk is still safer in bending compared to a normal young tree (with an

intact stem cross-section but still growing in height). This would mean that there is no need to

urgently reduce wind load. In addition, following the 1/3-rule (valid only for young trees still

growing in height having a centrally rotten zone in a circular stem), the natural tree-architecture

has a tolerance for losses in load carrying capacity of up to approximately 20% before probability

of failure increases significantly.





However, this estimation comes to limits in this case mainly due to these reasons:

> as soon as the remaining shell wall gets extremely thin (t/R < 1/10), fibre buckling and

other failure types (due to shear forces) may occur due to the relatively low torsional

strength of wood;

> as soon as the load carrying parts of the cross-section are not any more connected

mechanically to each other, the cross section cannot be described any more with this

model.

Consequently, in this case, the existing crown cables have to be maintained in order to ensure

that the cross-section does not split / crack up.

In addition,

> because the resistance drilling profiles show that the detected decay seems to be

progressing faster then the new ring width is compensating, I recommend a wind load

reduction (knowing that this reduces the tree's capability to defend the fungus). But, old

oak trees have the potential to recover from strong defects even with a smaller crown;

> because the neighbouring trees shall be removed in the near future, the wind load of the

oak will increase significantly.

Consequently, the crown will have to be reduced significantly but step-by-step over the next

years.





A step-by-step reduction

of finally approximately

this extent would reduce

wind load by about

65%. This amount of

reduction is a

consequence of the

combination of the

current defects and the

prognosis of the future

development of the shell

wall based on resistance

drilling profiles, taking

into account that the

neighbouring trees will

be taken down in the

future.

If the wind load will eventually increase even more due to additional site-changes (i.e. further

clearances around the tree), the required amount of reduction has to be re-evaluated. In addition

to the wind load reduction, a soil improvement should be carried out on the West side in the

same way as happened in the East, in order to improve the anchorage and root-support by

water, air, and nutrition.

A bi-annual visual inspection is required (with and without foliage) in order to detect any

significant changes as soon as possible.





4 Summary and conclusion

Some of the neighbouring trees protecting the oak since decades

from wind, are planned to be removed in the future for developing

the area with new buildings. Thus, the wind load may increase

significantly. Because previous inspections showed that the oak has

internal decay, the current extent of these deteriorations and their

impact on stability and safety had to be assessed in more detail in

order to be able to evaluate both current safety level as well as the

future perspective of this exceptional tree. Because of the more

than regional importance of this ‘Champion-Tree’, a thorough

inspection had to be carried out using stress-wave (‘sonic’)

tomography (ARBOTOM®), root diagnostics (ARBORADIXTM) and

resistance drilling with calibrated, ‘real’ RESISTOGRAPH® devices.

The sonic tomogram of the stem base reveals large internal decay

area (red) and strong/intact outer sections (green) leading to a

relative loss in load-carrying capacity of this cross-section of about

approximately 40%. Resistance drilling profiles reveal signs of

strong decay extension and narrowing tree-rings, thus weaker

compensatory growth. The sonic root plate analysis reveals a

significantly stronger anchorage on the East side, where the major

wind load came from and where soil improvement was carried out.

Recommendation:

1. Step-by-step crown reduction (see picture), leading to a

reduction in wind load by about 65%.

2. Soil improvement on the West side in the same way as happened

in the East, in order to improve the anchorage by better support

of roots with water, air and nutrition.

3. Continuos bi-annual visual inspection including maintenance of

existing crown cabling.





5 References and further reading

Bräker, O. U. 1981: Der Alterstrend bei Jahrringdichten undJahrringbreiten von Nadelhölzern und sein Ausgleich.Mitteilungen der forstlichen Bundesversuchsanstalt Wien142, S. 75-102.

Gere, J. M. and Timoshenko, S. P., 1997, Mechanics ofMaterials, PWS Publishing Company.

Kaczka R, Malik I, Owczarek P, Gärtner H, Helle G, HeinrichI (eds.) (2009): TRACE - Tree Rings in Archaeology,Climatology and Ecology, Vol. 7: Proceedings of theDENDROSYMPOSIUM 2008, April 27th–30th 2008,Zakopane, Poland. GFZ. Potsdam, Scientific TechnicalReport STR 09/03, Potsdam, p. 205-210.

Mattheck, Claus und Breloer, Helge 1994: The bodylanguage of trees. A handbook for failure analysis. Researchfor Amenity trees No. 4, HMSO Publications Centre. London1994. ISBN 0-11-753067-0.

Niklas, Karl J., Spatz, Hanns-Christof 2012: Plant Physics.Univ of Chicago Press. ISBN-10: 0226586324.

Rinn, F. 1988: A new method for measuring tree-ringdensity parameters. Physics diploma thesis, Institute forEnvironmental Physics, Heidelberg University, 85pp.

Rinn, F. 1990: Device for material testing, especially wood,by drill resistance measurements. German Patent 4122494.

Rinn, F., Becker, B., Kromer, B. 1990: Density Profiles ofCon i f e r s and Dec i duou s T r ees . P r o c eed ingsLund-Symposium on Tree Rings and Environment, LundUniversity.

Rinn, F. 1993: Catalogue of relative density profiles of trees,poles and t imber derived from RESISTOGRAPHmicro-drillings. Proc. 9th int. meeting non-destructivetesting, Madison 1993.

Rinn, F. 1994: Resistographic visualization of tree ringdensity variations. International Conference Tree Rings andEnvironment. Tucson, AZ, 1994. Printed in: Radiocarbon1996, pp. 871-878.

Rinn, F. 1994: One minute pole inspection withRESISTOGRAPH micro drillings. Proc. Int. Conf. on woodpoles and piles. Ft. Collins, Colorado, USA, March 1994.

Rinn, F. 1994: Resistographic inspection of building timber.Proc. Pacific Timber Engineering Conference. Gold Coast,Australia, July 1994.

Rinn, F., Schweingruber F.-H., Schär, E. 1996:RESISTOGRAPH and X-Ray Density Charts of Wood.Comparative Evaluation of Drill Resistance Profiles andX-Ray Density Charts of Different Wood Species.Holzforschung Vol. 50 (1996) pp. 303-311.

Rinn, F. 1996. Resistographic visualization of tree-ringdensity variations. In: J.S. Dean, D.M. Meko, and T.W.Swetnam, eds., Tree Rings, Environment, and Humanity.Radiocarbon 1996: 871-878.

Rinn, F. 2011: Basic Aspects of Mechanical Stability of TreeCross –Sections. Arborist News Feb 2011, pp. 52-54.

Rinn, F 2012: Basics of typical resistance-drilling profiles.

Western Arborist. Winter 2012.

Rinn, F. 2013: Detecting Fungal Decay in Palm Stems byResistance Drilling. Florida Arborist. Part I: Spring 2013. PartII: Summer 2013.

Rinn, F. 2013: Shell-wall thickness and breaking safety ofmature trees. Western Arborist. Fall 2013.

Spatz, H.-CH., Bruechert, F. 2000: Basic Biomechanics ofSelf-Supporting Plants: Wind loads and gravitational loadson a Norway spruce tree. Forest Ecology and Management,135, 33-44 (2000).

Spatz, Hanns–Christof; Niklas, Karl J.: Modes of failure intubular plant organs. Am. J. Bot. February 2013.

T e l e w s k i , F . W . a n d J a f f e M . J . 1 9 8 1 .Thigmomorphogenesis: Changes in the morphology andchemical composition induced by mechanical perturbation insix month old Pinus taeda seedlings. Canadian Journal ofForest Research 11:380-387.

Telewski, F.W. 1995: Wind Induced Physiological andDevelopmental Responses in Trees. IN: "Wind and Trees".M.P. Coutts and J. Grace, eds. pp. 237-263. CambridgeUniversity Press, Cambridge.

Telewski, F.W., Gardner, B.A., White, G., andPlovanich-Jones, A. 1997. Wind flow around multi-storeybuildings and its influence on tree growth. IN: PlantBiomechanics 1997: Conference Proceedings, 7-12September 1997, The University of Reading, UK. Vol. I pp.185-192.

Young, G. H. F., J. C. Demmler, B. E. Gunnarson, A. J.Kirchhefer, N. J. Loader, D. McCarroll: Age trends in treering growth and isotopic archives: A case study of Pinussylvestr is L. from northwestern Norway. GlobalBiogeochemical Cycles. 05/2013; ISBN: 0886-6236.

White, John 1998: Estimating the Age of Large and VeteranTrees in Britain. Forestry Commission. Edinburgh.

Winnistorfer, Paul M., Wimmer, Rupert 1995: Application ofa drill resistance technique for density profile measurementin wood composite panels. Forest Products Journal, Vol. 45,No. 6, p. 90-93, June 1995.





L I T E R A T U R E F O R D O W N L O A D

Lectures on tree diagnostics:

http://download.rinntech.com/Rinn_TreeSafety_2016.pdf

http://download.rinntech.com/RINN_TreeDiagnostics_2016.pdf

http://download.Rinntech.com/RINN_WoodAnatomy_2015.pdf

http://download.Rinntech.com/RINN_WindLoadAndPruning_2015.pdf

http://download.Rinntech.com/RINN_TreeRingAnalysisInArboriculture_2012.pdf

http://download.Rinntech.com/RINN_InternationalTreeInspection_Status_2014.pdf

Vorträge über Baumdiagnose:

http://download.rinntech.com/RINN_Oberhof_FehlerInDerBaumUntersuchung_2016.pdf

http://download.Rinntech.com/RINN_Regelwerke_Baumuntersuchung_2014.pdf

General publications on tree stability:

http://download.rinntech.com/RINN_CrossSectionShape_WesternArborist_Spring_2016.pdf

http://download.rinntech.com/RINN_TreeSizeRelations_WesternArborist_Winter_2015.pdf

http://download.Rinntech.com/RINN_WhenIsABottleneckDangerous_WesternArborist_Summer_2015.pdf

http://download.rinntech.com/Goodwin_on_RINN_HollowStems_ArbMag_Feb_2015.pdf

http://download.Rinntech.com/RINN_ErrorCalculationInTreeInspection_WesternArborist_Summer_2014.pdf

http://download.Rinntech.com/RINN_TreeWindLoad_WesternArborist_Spring_2014.pdf

http://download.Rinntech.com/RINN_MatureShellWalls_ISA_WesternArborist_Fall_2013.pdf

http://download.Rinntech.com/RINN_ArboristNews_Feb2011.pdf

Fachbeiträge über Baumstabilität:

http://download.Rinntech.com/RINN_Holzzentralblatt32_2015.pdf

http://download.Rinntech.com/RINN_BAUMZEITUNG_Klarstellung_2015.pdf

http://download.Rinntech.com/RINN_BAUMZEITUNG_Flaschenhals_2015.pdf

http://download.Rinntech.com/RINN_Baumzeitung_03_2013.pdf

Example tree report:

http://download.Rinntech.com/RINN_Oak_2013.pdf

http://download.Rinntech.com/RINN_Sedona_2013_CaseStudy.pdf

Beispiel-Gutachten:

http://download.Rinntech.com/RINN_Blasbach_Baumunfall_Gutachten_2004-5.pdf

http://download.Rinntech.com/RINN_Obertshausen_Unfall_2002.pdf

Allgemeine Grundlagen der Baum-Untersuchungen:

http://download.Rinntech.com/RINN_DS_DIN1319.pdf

http://download.Rinntech.com/RINN_AFZ_Dez2006_Fehlerrechnung.pdf

http://download.Rinntech.com/RINN_ZurFehlerrechnungInDerBaumkontrolle_ProBaum_1-2006_S12-20.pdf

http://download.Rinntech.com/RINN_GrundlagenDerFehlerrechnung.pdf

http://download.Rinntech.com/RINN_Regelwerke_Baumuntersuchung_2014.pdf

Resistance drilling:

http://download.Rinntech.com/RINN_InterpretingResistanceDrillingProfiles_WesternArborist_Fall_2015.pdf

http://download.Rinntech.com/RINN_TypicalTrendsInResistance_ISA-AN_Feb2014.pdf

http://download.Rinntech.com/RINN_BasicsOfResistanceDrilling_WCISAWinter2012.pdf





http://download.Rinntech.com/RINN_ISA_Florida_PalmArticle_2013.pdf

http://download.Rinntech.com/RINN_BasicsOfResistanceDrilling_Holztechnologie_2012_03.pdf

http://download.Rinntech.com/RINN_PracticalResistanceDrilling_Holztechnologie_2013_04.pdf

http://download.Rinntech.com/RINN_Holzforschung_1996.pdf

http://download.Rinntech.com/EcksteinSass_HaRuW_1994.PDF

http://download.Rinntech.com/RINN_ResistographicVisualizationOfTreeRingStructures_RADIOCARBON_1996.pdf

http://download.Rinntech.com/25YearsResistograph.pdf

Bohrwiderstandsmessungen:

http://download.Rinntech.com/RINN_Bohrwiderstandsprofile_Baumzeitung_05_2015.pdf

http://download.Rinntech.com/RINN_RisserkennungMitRESISTOGRAPH_Holztechnologie_04_2015.pdf

Sonic tomography:

http://download.Rinntech.com/RINN_CentralDefectsInSonicTreeTomography_WesternArborist_Spring_2015.pdf

http://download.Rinntech.com/RINN_SonicTreeTomography_SCAToday12_2014.pdf

http://download.rinntech.com/ConceptosBasicosDeTomografiaSonicaEnArboles.pdf

http://download.Rinntech.com/SIEGERT_PICUS_vs_ARBOTOM_2003.pdf

Schalltomographie:

http://download.Rinntech.com/RINN_2004_Holzanatomische_Grundlagen_der_Schalltomographie.pdf

http://download.Rinntech.com/RINN_Zahlenskalierung_von_Schalltomogrammen.pdf

http://download.Rinntech.com/RINN_Kleine_Schalltomographiefarrbenlehre_AFZ_08-2007_s404-405.pdf

http://download.Rinntech.com/RINN_AFZ12-2008-630-631_Wurzeldiagnose_mit_einem_Schalltomographen.pdf

http://download.Rinntech.com/RINN_StatischeHinweiseImTomogramm_2004.pdf

http://download.Rinntech.com/RINN_HolzanatomischeGrundlagenSchalltomographie_2003.pdf

http://download.Rinntech.com/RINN_TechnischeGrundlagenSchallTomographie_2003.pdf

http://download.Rinntech.com/SIEGERT_PICUS_vs_ARBOTOM_2003.pdf

Further download-links: send Email to [email protected]




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